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Ruby ReQL command reference

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Accessing ReQL

r

r → r

The top-level ReQL namespace.

Example: Setup your top-level namespace.

require 'rethinkdb'
include RethinkDB::Shortcuts

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connect

r.connect(opts={}) → connection

Create a new connection to the database server. Accepts the following options:

  • host: the host to connect to (default localhost).
  • port: the port to connect on (default 28015).
  • db: the default database (default test).
  • user: the user account to connect as (default admin).
  • password: the password for the user account to connect as (default '', empty).
  • timeout: timeout period in seconds for the connection to be opened (default 20).
  • ssl: a hash of options to support SSL connections (default nil). Currently, there is only one option available, and if the ssl option is specified, this key is required:
    • ca_certs: a path to the SSL CA certificate.

If the connection cannot be established, a ReqlDriverError exception will be thrown.

Example: Open a connection using the default host and port, specifying the default database.

conn = r.connect(:db => 'marvel')

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repl

connection.repl

Set the default connection to make REPL use easier. Allows calling .run on queries without specifying a connection.

Example: Set the default connection for the REPL, then call run without specifying the connection.

r.connect(:db => 'marvel').repl
r.table('heroes').run

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close

conn.close([{:noreply_wait => true}])

Close an open connection.

Example: Close an open connection, waiting for noreply writes to finish.

conn.close

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reconnect

conn.reconnect([{:noreply_wait => true}])

Close and reopen a connection.

Example: Cancel outstanding requests/queries that are no longer needed.

conn.reconnect(:noreply_wait => false)

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use

conn.use(db_name)

Change the default database on this connection.

Example: Change the default database so that we don’t need to specify the database when referencing a table.

conn.use('marvel')
r.table('heroes').run(conn) # refers to r.db('marvel').table('heroes')

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run

query.run(conn[, options]) → cursor

query.run(conn[, options]) → object

Run a query on a connection, returning either a single JSON result or a cursor, depending on the query.

Example: Run a query on the connection conn and print out every row in the result.

r.table('marvel').run(conn).each { |x| p x }

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changes

stream.changes([options) → stream

singleSelection.changes([options]) → stream

Turn a query into a changefeed, an infinite stream of objects representing changes to the query’s results as they occur. A changefeed may return changes to a table or an individual document (a “point” changefeed). Commands such as filter or map may be used before the changes command to transform or filter the output, and many commands that operate on sequences can be chained after changes.

Example: Subscribe to the changes on a table.

Start monitoring the changefeed in one client:

r.table('games').changes().run(conn).each{|change| p(change)}

As these queries are performed in a second client, the first client would receive and print the following objects:

> r.table('games').insert({:id => 1}).run(conn)
{:old_val => nil, :new_val => {:id => 1}}

> r.table('games').get(1).update({:player1 => 'Bob'}).run(conn)
{:old_val => {:id => 1}, :new_val => {:id => 1, :player1 => 'Bob'}}

> r.table('games').get(1).replace({:id => 1, :player1 => 'Bob', :player2 => 'Alice'}).run(conn)
{:old_val => {:id => 1, :player1 => 'Bob'},
 :new_val => {:id => 1, :player1 => 'Bob', :player2 => 'Alice'}}

> r.table('games').get(1).delete().run(conn)
{:old_val => {:id => 1, :player1 => 'Bob', :player2 => 'Alice'}, :new_val => nil}

> r.table_drop('games').run(conn)
ReqlRuntimeError: Changefeed aborted (table unavailable)

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noreply_wait

conn.noreply_wait

noreply_wait ensures that previous queries with the noreply flag have been processed by the server. Note that this guarantee only applies to queries run on the given connection.

Example: We have previously run queries with the noreply argument set to true. Now wait until the server has processed them.

conn.noreply_wait

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server

conn.server

Return information about the server being used by a connection.

Example: Return server information.

> conn.server

{
    :id => "404bef53-4b2c-433f-9184-bc3f7bda4a15",
    :name => "amadeus",
    :proxy => false
}

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em_run

query.em_run(conn[, options], block) → cursor

query.em_run(conn[, options], block) → object

Run a query asynchronously on a connection using EventMachine. If the query returns a sequence (including a stream), the block will be called once with each element of the sequence. Otherwise, the block will be called just once with the returned value.

Example: return a list of users in an EventMachine loop.

EventMachine.run {
  r.table('users').order_by(:index => 'username').em_run(conn) { |row|
    # do something with returned row data
    p row
  }
}

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Cursors

next

cursor.next([true])

Get the next element in the cursor.

Example: Retrieve the next element.

cursor = r.table('superheroes').run(conn)
doc = cursor.next()

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each

cursor.each { ... }

array.each { ... }

feed.each { ... }

Lazily iterate over a result set one element at a time.

Example: Let’s process all the elements!

cursor = r.table('users').run(conn)
cursor.each { |doc|
    process_row(doc)
}

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to_a

cursor.to_a()

Retrieve all results as an array.

Example: For small result sets it may be more convenient to process them at once as an array.

cursor = r.table('users').run()
users = cursor.to_a()
process_results(users)

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close

cursor.close

Close a cursor. Closing a cursor cancels the corresponding query and frees the memory associated with the open request.

Example: Close a cursor.

cursor.close

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Manipulating databases

db_create

r.db_create(db_name) → object

Create a database. A RethinkDB database is a collection of tables, similar to relational databases.

Example: Create a database named ‘superheroes’.

r.db_create('superheroes').run(conn)

{
    :config_changes => [
        {
            :new_val => {
                :id => "e4689cfc-e903-4532-a0e6-2d6797a43f07",
                :name => "superheroes"
            },
            :old_val => nil
        }
    ],
    :dbs_created => 1
}

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db_drop

r.db_drop(db_name) → object

Drop a database. The database, all its tables, and corresponding data will be deleted.

Example: Drop a database named ‘superheroes’.

r.db_drop('superheroes').run(conn)

{
    :config_changes => [
        {
            :old_val => {
                :id => "e4689cfc-e903-4532-a0e6-2d6797a43f07",
                :name => "superheroes"
            },
            :new_val => nil
        }
    ],
    :tables_dropped => 3,
    :dbs_dropped => 1
}

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db_list

r.db_list() → array

List all database names in the system. The result is a list of strings.

Example: List all databases.

r.db_list.run(conn)

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Manipulating tables

table_create

db.table_create(table_name[, options]) → object

r.table_create(table_name[, options]) → object

Create a table. A RethinkDB table is a collection of JSON documents.

Example: Create a table named ‘dc_universe’ with the default settings.

r.db('heroes').table_create('dc_universe').run(conn)

{
    :config_changes => [
        {
            :new_val => {
                :db => "test",
                :durability =>  "hard",
                :id => "20ea60d4-3b76-4817-8828-98a236df0297",
                :name => "dc_universe",
                :primary_key => "id",
                :shards => [
                    {
                        :primary_replica => "rethinkdb_srv1",
                        :replicas => [
                            "rethinkdb_srv1",
                            "rethinkdb_srv2"
                        ]
                    }
                ],
                :write_acks => "majority"
            },
            :old_val => nil
        }
    ],
    :tables_created => 1
}

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table_drop

db.table_drop(table_name) → object

Drop a table. The table and all its data will be deleted.

Example: Drop a table named ‘dc_universe’.

r.db('test').table_drop('dc_universe').run(conn)

{
    :config_changes => [
        {
            :old_val => {
                :db => "test",
                :durability =>  "hard",
                :id => "20ea60d4-3b76-4817-8828-98a236df0297",
                :name => "dc_universe",
                :primary_key => "id",
                :shards => [
                    {
                        :primary_replica => "rethinkdb_srv1",
                        :replicas => [
                            "rethinkdb_srv1",
                            "rethinkdb_srv2"
                        ]
                    }
                ],
                :write_acks => "majority"
            },
            :new_val => nil
        }
    ],
    :tables_dropped => 1
}

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table_list

db.table_list() → array

List all table names in a database. The result is a list of strings.

Example: List all tables of the ‘test’ database.

r.db('test').table_list().run(conn)

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index_create

table.index_create(index_name[, index_function][, :multi => false, :geo => false]) → object

Create a new secondary index on a table. Secondary indexes improve the speed of many read queries at the slight cost of increased storage space and decreased write performance. For more information about secondary indexes, read the article “Using secondary indexes in RethinkDB.”

Example: Create a simple index based on the field post_id.

r.table('comments').index_create('post_id').run(conn)

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index_drop

table.index_drop(index_name) → object

Delete a previously created secondary index of this table.

Example: Drop a secondary index named ‘code_name’.

r.table('dc').index_drop('code_name').run(conn)

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index_list

table.index_list() → array

List all the secondary indexes of this table.

Example: List the available secondary indexes for this table.

r.table('marvel').index_list().run(conn)

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index_rename

table.index_rename(old_index_name, new_index_name[, {:overwrite => false}]) → object

Rename an existing secondary index on a table. If the optional argument overwrite is specified as true, a previously existing index with the new name will be deleted and the index will be renamed. If overwrite is false (the default) an error will be raised if the new index name already exists.

Example: Rename an index on the comments table.

r.table('comments').index_rename('post_id', 'message_id').run(conn)

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index_status

table.index_status([, index...]) → array

Get the status of the specified indexes on this table, or the status of all indexes on this table if no indexes are specified.

Example: Get the status of all the indexes on test:

r.table('test').index_status.run(conn)

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index_wait

table.index_wait([, index...]) → array

Wait for the specified indexes on this table to be ready, or for all indexes on this table to be ready if no indexes are specified.

Example: Wait for all indexes on the table test to be ready:

r.table('test').index_wait.run(conn)

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set_write_hook

table.set_write_hook(function | binary | null) → object

Sets the write hook on a table or overwrites it if one already exists.

The function can be an anonymous function with the signature (context: object, old_val: object, new_val: object) -> object or a binary representation obtained from the function field of get_write_hook. The function must be deterministic, and so cannot use a subquery or the r.js command.

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get_write_hook

table.get_write_hook() → null/object

Gets the write hook of this table. If a write hook exists, the result is an object of the following form:

{
  :function => <binary>,
  :query => "setWriteHook(function(_var1, _var2, _var3) { return ...; })"
}

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Writing data

insert

table.insert(object | [object1, object2, ...][, :durability => "hard", :return_changes => false, :conflict => "error"]) → object

Insert documents into a table. Accepts a single document or an array of documents.

Example: Insert a document into the table posts.

r.table("posts").insert({
    :id => 1,
    :title => "Lorem ipsum",
    :content => "Dolor sit amet"
}).run(conn)

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update

table.update(object | function[, :durability => "hard", :return_changes => false, :non_atomic => false]) → object

selection.update(object | function[, :durability => "hard", :return_changes => false, :non_atomic => false]) → object

singleSelection.update(object | function[, :durability => "hard", :return_changes => false, :non_atomic => false]) → object

Update JSON documents in a table. Accepts a JSON document, a ReQL expression, or a combination of the two.

Example: Update the status of the post with id of 1 to published.

r.table("posts").get(1).update({:status => "published"}).run(conn)

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replace

table.replace(object | function[, :durability => "hard", :return_changes => false, :non_atomic => false]) → object

selection.replace(object | function[, :durability => "hard", :return_changes => false, :non_atomic => false]) → object

singleSelection.replace(object | function[, :durability => "hard", :return_changes => false, :non_atomic => false]) → object

Replace documents in a table. Accepts a JSON document or a ReQL expression, and replaces the original document with the new one. The new document must have the same primary key as the original document.

Example: Replace the document with the primary key 1.

r.table("posts").get(1).replace({
    :id => 1,
    :title => "Lorem ipsum",
    :content => "Aleas jacta est",
    :status => "draft"
}).run(conn)

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delete

table.delete[({:durability => "hard", :return_changes => false})] → object

selection.delete[({:durability => "hard", :return_changes => false})] → object

singleSelection.delete[({:durability => "hard", :return_changes => false})] → object

Delete one or more documents from a table.

Example: Delete a single document from the table comments.

r.table("comments").get("7eab9e63-73f1-4f33-8ce4-95cbea626f59").delete.run(conn)

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sync

table.sync() → object

sync ensures that writes on a given table are written to permanent storage. Queries that specify soft durability ({:durability => soft}) do not give such guarantees, so sync can be used to ensure the state of these queries. A call to sync does not return until all previous writes to the table are persisted.

Example: After having updated multiple heroes with soft durability, we now want to wait until these changes are persisted.

r.table('marvel').sync().run(conn)

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Selecting data

db

r.db(db_name) → db

Reference a database.

Example: Explicitly specify a database for a query.

r.db('heroes').table('marvel').run(conn)

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table

db.table(name[, {:read_mode => 'single', :identifier_format => 'name'}) → table

Return all documents in a table. Other commands may be chained after table to return a subset of documents (such as get and filter) or perform further processing.

Example: Return all documents in the table ‘marvel’ of the default database.

r.table('marvel').run(conn)

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get

table.get(key) → singleRowSelection

Get a document by primary key.

Example: Find a document by UUID.

r.table('posts').get('a9849eef-7176-4411-935b-79a6e3c56a74').run(conn)

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get_all

table.get_all([key, key2...], [, :index => 'id']) → selection

Get all documents where the given value matches the value of the requested index.

Example: Secondary index keys are not guaranteed to be unique so we cannot query via get when using a secondary index.

r.table('marvel').get_all('man_of_steel', :index => 'code_name').run(conn)

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between

table.between(lower_key, upper_key[, options]) → table_slice

table_slice.between(lower_key, upper_key[, options]) → table_slice

Get all documents between two keys. Accepts three optional arguments: index, left_bound, and right_bound. If index is set to the name of a secondary index, between will return all documents where that index’s value is in the specified range (it uses the primary key by default). left_bound or right_bound may be set to open or closed to indicate whether or not to include that endpoint of the range (by default, left_bound is closed and right_bound is open).

Example: Find all users with primary key >= 10 and < 20 (a normal half-open interval).

r.table('marvel').between(10, 20).run(conn)

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filter

selection.filter(predicate_function[, :default => false]) → selection

stream.filter(predicate_function[, :default => false]) → stream

array.filter(predicate_function[, :default => false]) → array

Return all the elements in a sequence for which the given predicate is true. The return value of filter will be the same as the input (sequence, stream, or array). Documents can be filtered in a variety of ways—ranges, nested values, boolean conditions, and the results of anonymous functions.

Example: Get all users who are 30 years old.

r.table('users').filter({:age => 30}).run(conn)

The predicate {'age': 30} selects documents in the users table with an age field whose value is 30. Documents with an age field set to any other value or with no age field present are skipped.

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Joins

inner_join

sequence.inner_join(other_sequence, predicate_function) → stream

array.inner_join(other_sequence, predicate_function) → array

Returns an inner join of two sequences.

Example: Return a list of all matchups between Marvel and DC heroes in which the DC hero could beat the Marvel hero in a fight.

r.table('marvel').inner_join(r.table('dc')) {|marvel_row, dc_row|
    marvel_row[:strength] < dc_row[:strength]
}.zip().run(conn)

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outer_join

sequence.outer_join(other_sequence, predicate_function) → stream

array.outer_join(other_sequence, predicate_function) → array

Returns a left outer join of two sequences. The returned sequence represents a union of the left-hand sequence and the right-hand sequence: all documents in the left-hand sequence will be returned, each matched with a document in the right-hand sequence if one satisfies the predicate condition. In most cases, you will want to follow the join with zip to combine the left and right results.

Example: Return a list of all Marvel heroes, paired with any DC heroes who could beat them in a fight.

r.table('marvel').outer_join(r.table('dc')) {|marvel_row, dc_row|
    marvel_row[:strength] < dc_row[:strength]
}.run(conn)

(Compare this to an inner_join with the same inputs and predicate, which would return a list only of the matchups in which the DC hero has the higher strength.)

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eq_join

sequence.eq_join(left_field, right_table[, :index => 'id', :ordered => false]) → sequence

sequence.eq_join(function, right_table[, :index => 'id', :ordered => false]) → sequence

Join tables using a field or function on the left-hand sequence matching primary keys or secondary indexes on the right-hand table. eq_join is more efficient than other ReQL join types, and operates much faster. Documents in the result set consist of pairs of left-hand and right-hand documents, matched when the field on the left-hand side exists and is non-null and an entry with that field’s value exists in the specified index on the right-hand side.

Example: Match players with the games they’ve played against one another.

Join these tables using game_id on the player table and id on the games table:

r.table('players').eq_join('game_id', r.table('games')).run(conn)

This will return a result set such as the following:

[
    {
        'left' => { 'game_id' => 3, 'id' => 2, 'player' => "Agatha" },
        'right' => { 'id' => 3, 'field' => "Bucklebury" }
    },
    {
        'left' => { 'game_id' => 2, 'id' => 3, 'player' => "Fred" },
        'right' => { 'id' => 2, 'field' => "Rushock Bog" }
    },
    ...
]

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zip

stream.zip() → stream

array.zip() → array

Used to ‘zip’ up the result of a join by merging the ‘right’ fields into ‘left’ fields of each member of the sequence.

Example: ‘zips up’ the sequence by merging the left and right fields produced by a join.

r.table('marvel').eq_join(:main_dc_collaborator, r.table('dc')).zip.run(conn)

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Transformations

map

sequence1.map([sequence2, ...], function) → stream

array1.map([array2, ...], function) → array

r.map(sequence1[, sequence2, ...], function) → stream

r.map(array1[, array2, ...], function) → array

Transform each element of one or more sequences by applying a mapping function to them. If map is run with two or more sequences, it will iterate for as many items as there are in the shortest sequence.

Example: Return the first five squares.

> r.expr([1, 2, 3, 4, 5]).map{ |val| (val * val) }.run(conn)

[1, 4, 9, 16, 25]

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with_fields

sequence.with_fields([selector1, selector2...]) → stream

array.with_fields([selector1, selector2...]) → array

Plucks one or more attributes from a sequence of objects, filtering out any objects in the sequence that do not have the specified fields. Functionally, this is identical to has_fields followed by pluck on a sequence.

Example: Get a list of users and their posts, excluding any users who have not made any posts.

Existing table structure:

[
    { :id => 1, :user => 'bob', :email => 'bob@foo.com', :posts => [ 1, 4, 5 ] },
    { :id => 2, :user => 'george', :email => 'george@foo.com' },
    { :id => 3, :user => 'jane', :email => 'jane@foo.com', :posts => [ 2, 3, 6 ] }
]

Command and output:

r.table('users').with_fields('id', 'user', 'posts').run(conn)

[
    { :id => 1, :user => 'bob', :posts => [ 1, 4, 5 ] },
    { :id => 3, :user => 'jane', :posts => [ 2, 3, 6 ] }
]

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concat_map

stream.concat_map(function) → stream

array.concat_map(function) → array

Concatenate one or more elements into a single sequence using a mapping function.

Example: Construct a sequence of all monsters defeated by Marvel heroes. The field “defeatedMonsters” is an array of one or more monster names.

r.table('marvel').concat_map { |hero|
    hero[:defeated_monsters]
}.run(conn)

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order_by

table.order_by([key | function], :index => index_name) → table_slice

selection.order_by(key | function[, ...]) → selection<array>

sequence.order_by(key | function[, ...]) → array

Sort the sequence by document values of the given key(s). To specify the ordering, wrap the attribute with either r.asc or r.desc (defaults to ascending).

Example: Order all the posts using the index date.

r.table('posts').order_by(:index => 'date').run(conn)

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skip

sequence.skip(n) → stream

array.skip(n) → array

Skip a number of elements from the head of the sequence.

Example: Here in conjunction with order_by we choose to ignore the most successful heroes.

r.table('marvel').order_by(:success_metric).skip(10).run(conn)

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limit

sequence.limit(n) → stream

array.limit(n) → array

End the sequence after the given number of elements.

Example: Only so many can fit in our Pantheon of heroes.

r.table('marvel').order_by(:belovedness).limit(10).run(conn)

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slice, []

selection.slice(start_offset[, end_offset, :left_bound => 'closed', :right_bound =>'open']) → selection

stream.slice(start_offset[, end_offset, :left_bound => 'closed', :right_bound =>'open']) → stream

array.slice(start_offset[, end_offset, :left_bound => 'closed', :right_bound =>'open']) → array

binary.slice(start_offset[, end_offset, :left_bound => 'closed', :right_bound =>'open']) → binary

string.slice(start_offset[, end_offset, :left_bound => 'closed', :right_bound =>'open']) → string

Return the elements of a sequence within the specified range.

Example: Return the fourth, fifth and sixth youngest players. (The youngest player is at index 0, so those are elements 3–5.)

r.table('players').order_by(:index => 'age').slice(3,6).run(conn)

Or, using Ruby’s range operator:

r.table('players').filter({'class': 'amateur'})[10..19].run(conn)

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nth

sequence.nth(index) → object

selection.nth(index) → selection<object>

Get the nth element of a sequence, counting from zero. If the argument is negative, count from the last element.

Example: Select the second element in the array.

r.expr([1,2,3]).nth(1).run(conn)
r.expr([1,2,3])[1].run(conn)

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offsets_of

sequence.offsets_of(datum | predicate_function) → array

Get the indexes of an element in a sequence. If the argument is a predicate, get the indexes of all elements matching it.

Example: Find the position of the letter ‘c’.

r.expr(['a','b','c']).offsets_of('c').run(conn)

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is_empty

sequence.is_empty() → bool

Test if a sequence is empty.

Example: Are there any documents in the marvel table?

r.table('marvel').is_empty().run(conn)

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union

stream.union(sequence[, sequence, ...][, :interleave => true]) → stream

array.union(sequence[, sequence, ...][, :interleave => true]) → array

r.union(stream, sequence[, sequence, ...][, :interleave => true]) → stream

r.union(array, sequence[, sequence, ...][, :interleave => true]) → array

Merge two or more sequences.

Example: Construct a stream of all heroes.

r.table('marvel').union(r.table('dc')).run(conn)

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sample

sequence.sample(number) → selection

stream.sample(number) → array

array.sample(number) → array

Select a given number of elements from a sequence with uniform random distribution. Selection is done without replacement.

Example: Select 3 random heroes.

r.table('marvel').sample(3).run(conn)

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Aggregation

group

sequence.group(field | function..., [:index => <indexname>, :multi => true]) → grouped_stream

r.group(sequence, field | function..., [:index => <indexname>, :multi => true]) → grouped_stream

Takes a stream and partitions it into multiple groups based on the fields or functions provided.

Example: Group games by player.

> r.table('games').group('player').run(conn)

{
    "Alice" => [
        {"id" => 5, "player" => "Alice", "points" => 7, "type" => "free"},
        {"id" => 12, "player" => "Alice", "points" => 2, "type" => "free"}
    ],
    "Bob" => [
        {"id" => 2, "player" => "Bob", "points" => 15, "type" => "ranked"},
        {"id" => 11, "player" => "Bob", "points" => 10, "type" => "free"}
    ]
}

Read more about this command →

ungroup

grouped_stream.ungroup() → array

grouped_data.ungroup() → array

Takes a grouped stream or grouped data and turns it into an array of objects representing the groups. Any commands chained after ungroup will operate on this array, rather than operating on each group individually. This is useful if you want to e.g. order the groups by the value of their reduction.

Example: What is the maximum number of points scored by each player, with the highest scorers first?

r.table('games')
   .group('player').max('points')['points']
   .ungroup().order_by(r.desc('reduction')).run(conn)

Read more about this command →

reduce

sequence.reduce(function) → value

r.reduce(sequence, function) → value

Produce a single value from a sequence through repeated application of a reduction function.

Example: Return the numbers of documents in the table posts.

r.table("posts").map{|doc| 1 }
    .reduce{ |left, right| left+right }
    .default(0).run(conn)

A shorter way to execute this query is to use count.

Read more about this command →

fold

sequence.fold(base, function) → value

sequence.fold(base, function, :emit => function[, :final_emit => function]) → sequence

Apply a function to a sequence in order, maintaining state via an accumulator. The fold command returns either a single value or a new sequence.

Example: Concatenate words from a list.

r.table('words').order_by('id').fold('',
    lambda { |acc, word| acc + r.branch(acc.eq(''), '', ', ') + word }
).run(conn)

(This example could be implemented with reduce, but fold will preserve the order when words is a RethinkDB table or other stream, which is not guaranteed with reduce.)

Read more about this command →

count

sequence.count([value | predicate_function]) → number

binary.count() → number

string.count() → number

object.count() → number

r.count(sequence | binary | string | object[, predicate_function]) → number

Counts the number of elements in a sequence or key/value pairs in an object, or returns the size of a string or binary object.

Example: Count the number of users.

r.table('users').count().run(conn)

Read more about this command →

sum

sequence.sum([field | function]) → number

r.sum(sequence, [field | function]) → number

Sums all the elements of a sequence. If called with a field name, sums all the values of that field in the sequence, skipping elements of the sequence that lack that field. If called with a function, calls that function on every element of the sequence and sums the results, skipping elements of the sequence where that function returns nil or a non-existence error.

Example: What’s 3 + 5 + 7?

r([3, 5, 7]).sum().run(conn)

Read more about this command →

avg

sequence.avg([field | function]) → number

r.avg(sequence, [field | function]) → number

Averages all the elements of a sequence. If called with a field name, averages all the values of that field in the sequence, skipping elements of the sequence that lack that field. If called with a function, calls that function on every element of the sequence and averages the results, skipping elements of the sequence where that function returns nil or a non-existence error.

Example: What’s the average of 3, 5, and 7?

r([3, 5, 7]).avg().run(conn)

Read more about this command →

min

sequence.min(field | function) → element

sequence.min({:index => <indexname>}) → element

r.min(sequence, field | function) → element

r.min(sequence, {:index => <indexname>}) → element

Finds the minimum element of a sequence.

Example: Return the minimum value in the list [3, 5, 7].

r([3, 5, 7]).min().run(conn)

Read more about this command →

max

sequence.max(field | function) → element

sequence.max({:index => <indexname>}) → element

r.max(sequence, field | function) → element

r.max(sequence, {:index => <indexname>}) → element

Finds the maximum element of a sequence.

Example: Return the maximum value in the list [3, 5, 7].

r([3, 5, 7]).max().run(conn)

Read more about this command →

distinct

sequence.distinct() → array

table.distinct([:index => <indexname>]) → stream

r.distinct(sequence) → array

r.distinct(table, [:index => <indexname>]) → stream

Removes duplicate elements from a sequence.

Example: Which unique villains have been vanquished by Marvel heroes?

r.table('marvel').concat_map{|hero| hero[:villain_list]}.distinct.run(conn)

Read more about this command →

contains

sequence.contains([value | predicate_function, ...]) → bool

r.contains(sequence, [value | predicate_function, ...]) → bool

When called with values, returns true if a sequence contains all the specified values. When called with predicate functions, returns true if for each predicate there exists at least one element of the stream where that predicate returns true.

Example: Has Iron Man ever fought Superman?

r.table('marvel').get('ironman')[:opponents].contains('superman').run(conn)

Read more about this command →

Document manipulation

pluck

sequence.pluck([selector1, selector2...]) → stream

array.pluck([selector1, selector2...]) → array

object.pluck([selector1, selector2...]) → object

singleSelection.pluck([selector1, selector2...]) → object

Plucks out one or more attributes from either an object or a sequence of objects (projection).

Example: We just need information about IronMan’s reactor and not the rest of the document.

r.table('marvel').get('IronMan').pluck('reactorState', 'reactorPower').run(conn)

Read more about this command →

without

sequence.without([selector1, selector2...]) → stream

array.without([selector1, selector2...]) → array

singleSelection.without([selector1, selector2...]) → object

object.without([selector1, selector2...]) → object

The opposite of pluck; takes an object or a sequence of objects, and returns them with the specified paths removed.

Example: Since we don’t need it for this computation we’ll save bandwidth and leave out the list of IronMan’s romantic conquests.

r.table('marvel').get('IronMan').without('personalVictoriesList').run(conn)

Read more about this command →

merge

singleSelection.merge([object | function, object | function, ...]) → object

object.merge([object | function, object | function, ...]) → object

sequence.merge([object | function, object | function, ...]) → stream

array.merge([object | function, object | function, ...]) → array

Merge two or more objects together to construct a new object with properties from all. When there is a conflict between field names, preference is given to fields in the rightmost object in the argument list. merge also accepts a subquery function that returns an object, which will be used similarly to a map function.

Example: Equip Thor for battle.

r.table('marvel').get('thor').merge(
    r.table('equipment').get('hammer'),
    r.table('equipment').get('pimento_sandwich')
).run(conn)

Read more about this command →

append

array.append(value) → array

Append a value to an array.

Example: Retrieve Iron Man’s equipment list with the addition of some new boots.

r.table('marvel').get('IronMan')[:equipment].append('new_boots').run(conn)

Read more about this command →

prepend

array.prepend(value) → array

Prepend a value to an array.

Example: Retrieve Iron Man’s equipment list with the addition of some new boots.

r.table('marvel').get('IronMan')[:equipment].prepend('new_boots').run(conn)

Read more about this command →

difference

array.difference(array) → array

Remove the elements of one array from another array.

Example: Retrieve Iron Man’s equipment list without boots.

r.table('marvel').get('IronMan')[:equipment].difference(['Boots']).run(conn)

Read more about this command →

set_insert

array.set_insert(value) → array

Add a value to an array and return it as a set (an array with distinct values).

Example: Retrieve Iron Man’s equipment list with the addition of some new boots.

r.table('marvel').get('IronMan')[:equipment].set_insert('new_boots').run(conn)

Read more about this command →

set_union

array.set_union(array) → array

Add a several values to an array and return it as a set (an array with distinct values).

Example: Retrieve Iron Man’s equipment list with the addition of some new boots and an arc reactor.

r.table('marvel').get('IronMan')[:equipment].set_union(['newBoots', 'arc_reactor']).run(conn)

Read more about this command →

set_intersection

array.set_intersection(array) → array

Intersect two arrays returning values that occur in both of them as a set (an array with distinct values).

Example: Check which pieces of equipment Iron Man has from a fixed list.

r.table('marvel').get('IronMan')[:equipment].set_intersection(['newBoots', 'arc_reactor']).run(conn)

Read more about this command →

set_difference

array.set_difference(array) → array

Remove the elements of one array from another and return them as a set (an array with distinct values).

Example: Check which pieces of equipment Iron Man has, excluding a fixed list.

r.table('marvel').get('IronMan')[:equipment].set_difference(['newBoots', 'arc_reactor']).run(conn)

Read more about this command →

[] (bracket)

sequence[attr] → sequence

singleSelection[attr] → value

object[attr] → value

array[index] → value

Get a single field from an object. If called on a sequence, gets that field from every object in the sequence, skipping objects that lack it.

Example: What was Iron Man’s first appearance in a comic?

r.table('marvel').get('IronMan')[:first_appearance].run(conn)

Read more about this command →

get_field

sequence.get_field(attr) → sequence

singleSelection.get_field(attr) → value

object.get_field(attr) → value

Get a single field from an object. If called on a sequence, gets that field from every object in the sequence, skipping objects that lack it.

Example: What was Iron Man’s first appearance in a comic?

r.table('marvel').get('IronMan').get_field('first_appearance').run(conn)

Read more about this command →

has_fields

sequence.has_fields([selector1, selector2...]) → stream

array.has_fields([selector1, selector2...]) → array

object.has_fields([selector1, selector2...]) → boolean

Test if an object has one or more fields. An object has a field if it has that key and the key has a non-null value. For instance, the object {'a': 1,'b': 2,'c': null} has the fields a and b.

Example: Return the players who have won games.

r.table('players').has_fields(:games_won).run(conn)

Read more about this command →

insert_at

array.insert_at(offset, value) → array

Insert a value in to an array at a given index. Returns the modified array.

Example: Hulk decides to join the avengers.

r.expr(["Iron Man", "Spider-Man"]).insert_at(1, "Hulk").run(conn)

Read more about this command →

splice_at

array.splice_at(offset, array) → array

Insert several values in to an array at a given index. Returns the modified array.

Example: Hulk and Thor decide to join the avengers.

r.expr(["Iron Man", "Spider-Man"]).splice_at(1, ["Hulk", "Thor"]).run(conn)

Read more about this command →

delete_at

array.delete_at(offset [,end_offset]) → array

Remove one or more elements from an array at a given index. Returns the modified array. (Note: delete_at operates on arrays, not documents; to delete documents, see the delete command.)

Example: Delete the second element of an array.

> r.expr(['a','b','c','d','e','f']).delete_at(1).run(conn)

['a', 'c', 'd', 'e', 'f']

Read more about this command →

change_at

array.change_at(offset, value) → array

Change a value in an array at a given index. Returns the modified array.

Example: Bruce Banner hulks out.

r.expr(["Iron Man", "Bruce", "Spider-Man"]).change_at(1, "Hulk").run(conn)

Read more about this command →

keys

singleSelection.keys() → array

object.keys() → array

Return an array containing all of an object’s keys. Note that the keys will be sorted as described in ReQL data types (for strings, lexicographically).

Example: Get all the keys from a table row.

# row: { :id => 1, :mail => "fred@example.com", :name => "fred" }

r.table('users').get(1).keys().run(conn)

> [ "id", "mail", "name" ]

Read more about this command →

values

singleSelection.values() → array

object.values() → array

Return an array containing all of an object’s values. values() guarantees the values will come out in the same order as keys.

Example: Get all of the values from a table row.

# row: { :id => 1, :mail => "fred@example.com", :name => "fred" }

r.table('users').get(1).values().run(conn)

> [ 1, "fred@example.com", "fred" ]

Read more about this command →

literal

r.literal(object) → special

Replace an object in a field instead of merging it with an existing object in a merge or update operation. Using literal with no arguments in a merge or update operation will remove the corresponding field.

Example: Replace one nested document with another rather than merging the fields.

r.table('users').get(1).update({ :data => r.literal({ :age => 19, :job => 'Engineer' }) }).run(conn)

{
    :id => 1,
    :name => "Alice",
    :data => {
        :age => 19,
        :job => "Engineer"
    }
}

Read more about this command →

object

r.object([key, value,]...) → object

Creates an object from a list of key-value pairs, where the keys must be strings. r.object(A, B, C, D) is equivalent to r.expr([[A, B], [C, D]]).coerce_to('OBJECT').

Example: Create a simple object.

> r.object('id', 5, 'data', ['foo', 'bar']).run(conn)
{data: ["foo", "bar"], id: 5}

Read more about this command →

String manipulation

match

string.match(regexp) → nil/object

Matches against a regular expression. If there is a match, returns an object with the fields:

  • str: The matched string
  • start: The matched string’s start
  • end: The matched string’s end
  • groups: The capture groups defined with parentheses

If no match is found, returns nil.

Example: Get all users whose name starts with “A”. Because nil evaluates to false in filter, you can just use the result of match for the predicate.

r.table('users').filter{ |doc|
    doc['name'].match("^A")
}.run(conn)

Read more about this command →

split

string.split([separator, [max_splits]]) → array

Splits a string into substrings. Splits on whitespace when called with no arguments. When called with a separator, splits on that separator. When called with a separator and a maximum number of splits, splits on that separator at most max_splits times. (Can be called with nil as the separator if you want to split on whitespace while still specifying max_splits.)

Example: Split on whitespace.

> r.expr("foo  bar bax").split().run(conn)
["foo", "bar", "bax"]

Read more about this command →

upcase

string.upcase() → string

Uppercases a string.

Example:

> r.expr("Sentence about LaTeX.").upcase().run(conn)
"SENTENCE ABOUT LATEX."

Note: upcase and downcase only affect ASCII characters.

Read more about this command →

downcase

string.downcase() → string

Lowercases a string.

Example:

> r.expr("Sentence about LaTeX.").downcase().run(conn)
"sentence about latex."

Note: upcase and downcase only affect ASCII characters.

Read more about this command →

Math and logic

+

value + value → value

time + number → time

value.add(value[, value, ...]) → value

time.add(number[, number, ...]) → time

Sum two or more numbers, or concatenate two or more strings or arrays.

Example: It’s as easy as 2 + 2 = 4.

> (r.expr(2) + 2).run(conn)

4

Read more about this command →

-

number - number → number

time - number → time

time - time → number

number.sub(number[, number, ...]) → number

time.sub(number[, number, ...]) → time

time.sub(time) → number

Subtract two numbers.

Example: It’s as easy as 2 - 2 = 0.

(r.expr(2) - 2).run(conn)

Read more about this command →

*

number * number → number

array * number → array

number.mul(number[, number, ...]) → number

array.mul(number[, number, ...]) → array

Multiply two or more numbers, or make a periodic array.

Example: It’s as easy as 2 * 2 = 4.

(r.expr(2) * 2).run(conn)

Read more about this command →

/

number / number → number

number.div(number[, number ...]) → number

Divide two numbers.

Example: It’s as easy as 2 / 2 = 1.

(r.expr(2) / 2).run(conn)

Read more about this command →

%

number % number → number

Find the remainder when dividing two numbers.

Example: It’s as easy as 2 % 2 = 0.

(r.expr(2) % 2).run(conn)

Read more about this command →

&, and

bool & bool → bool

bool.and([bool, bool, ...]) → bool

r.and([bool, bool, ...]) → bool

Compute the logical “and” of one or more values.

Example: Return whether both a and b evaluate to true.

> a = true
> b = false
> (r.expr(a) & b).run(conn)

false

Read more about this command →

|, or

bool | bool → bool

bool.or([bool, bool, ...]) → bool

r.or([bool, bool, ...]) → bool

Compute the logical “or” of one or more values.

Example: Return whether either a or b evaluate to true.

> a = true
> b = false
> (r.expr(a) | b).run(conn)

true

Read more about this command →

eq

value.eq(value[, value, ...]) → bool

Test if two or more values are equal.

Example: See if a user’s role field is set to administrator.

r.table('users').get(1)['role'].eq('administrator').run(conn)

Read more about this command →

ne

value.ne(value[, value, ...]) → bool

Test if two or more values are not equal.

Example: See if a user’s role field is not set to administrator.

r.table('users').get(1)['role'].ne('administrator').run(conn)

Read more about this command →

>, gt

value.gt(value[, value, ...]) → bool

value > value → bool

Compare values, testing if the left-hand value is greater than the right-hand.

Example: Test if a player has scored more than 10 points.

r.table('players').get(1)['score'].gt(10).run(conn)
# alternative syntax
(r.table('players').get(1)['score'] > 10).run(conn)

Read more about this command →

>=, ge

value.ge(value[, value, ...]) → bool

value >= value → bool

Compare values, testing if the left-hand value is greater than or equal to the right-hand.

Example: Test if a player has scored 10 points or more.

r.table('players').get(1)['score'].ge(10).run(conn)
# alternative syntax
(r.table('players').get(1)['score'] >= 10).run(conn)

Read more about this command →

<, lt

value.lt(value[, value, ...]) → bool

value < value → bool

Compare values, testing if the left-hand value is less than the right-hand.

Example: Test if a player has scored less than 10 points.

r.table('players').get(1)['score'].lt(10).run(conn)
# alternative syntax
(r.table('players').get(1)['score'] < 10).run(conn)

Read more about this command →

<=, le

value.le(value[, value, ...]) → bool

value <= value → bool

Compare values, testing if the left-hand value is less than or equal to the right-hand.

Example: Test if a player has scored 10 points or less.

r.table('players').get(1)['score'].le(10).run(conn)
# alternative syntax
(r.table('players').get(1)['score'] <= 10).run(conn)

Read more about this command →

not

bool.not() → bool

not(bool) → bool

Compute the logical inverse (not) of an expression.

Example: Not true is false.

r(true).not().run(conn)
r.not(true).run(conn)

These evaluate to false.

Read more about this command →

bit_and

r.bit_and(number) → number

r.bit_and(number[, number, ...]) → number

Compute the arithmetic “and” of one or more values. bit_and takes one or more arguments.

Example: Compute the arithmetic “and” of 6 and 4

r.expr(6).bit_and(4).run(conn)

Read more about this command →

bit_or

r.bit_or(number) → number

r.bit_or(number[, number, ...]) → number

Compute the arithmetic “or” of one or more values. bit_or takes one or more arguments.

Example: Compute the arithmetic “or” of 6 and 4

r.expr(6).bit_or(4).run(conn)

Read more about this command →

bit_xor

r.bit_xor(number) → number

r.bit_xor(number[, number, ...]) → number

Compute the arithmetic “and” of one or more values. bit_xor takes one or more arguments.

Example: Compute the arithmetic “and” of 6 and 4

r.expr(6).bit_xor(4).run(conn)

Read more about this command →

bit_not

r.bit_not() → number

Compute the arithmetic inverse (not) of an expression. bit_not takes no arguments.

Example: Negate the arithmetice expression

r.expr(15).bit_not().run(conn)

Read more about this command →

bit_sal

r.bit_sal(number) → number

r.bit_sal(number[, number, ...]) → number

Compute the left arithmetic shift (left logical shift) of one or more values. bit_sal takes one or more arguments.

Example: Compute the left arithmetic shift of 5 and 4

r.expr(5).bit_sal(4).run(conn)

Read more about this command →

bit_sar

r.bit_sar(number) → number

r.bit_sar(number[, number, ...]) → number

Compute the right arithmetic shift of one or more values. bit_sar takes one or more arguments.

Example: Compute the right arithmetic shift of 32 and 3

r.expr(32).bit_sar(3).run(conn)

Read more about this command →

random

r.random() → number

r.random(number[, number], :float => true) → number

r.random(integer[, integer]) → integer

Generate a random number between given (or implied) bounds. random takes zero, one or two arguments.

Example: Generate a random number in the range [0,1)

r.random().run(conn)

Read more about this command →

round

r.round(number) → number

number.round() → number

Rounds the given value to the nearest whole integer.

Example: Round 12.345 to the nearest integer.

> r.round(12.345).run(conn)

12.0

The round command can also be chained after an expression.

Read more about this command →

ceil

r.ceil(number) → number

number.ceil() → number

Rounds the given value up, returning the smallest integer value greater than or equal to the given value (the value’s ceiling).

Example: Return the ceiling of 12.345.

> r.ceil(12.345).run(conn)

13.0

The ceil command can also be chained after an expression.

Read more about this command →

floor

r.floor(number) → number

number.floor() → number

Rounds the given value down, returning the largest integer value less than or equal to the given value (the value’s floor).

Example: Return the floor of 12.345.

> r.floor(12.345).run(conn)

12.0

The floor command can also be chained after an expression.

Read more about this command →

Dates and times

now

r.now() → time

Return a time object representing the current time in UTC. The command now() is computed once when the server receives the query, so multiple instances of r.now() will always return the same time inside a query.

Example: Add a new user with the time at which he subscribed.

r.table("users").insert({
    :name => "John",
    :subscription_date => r.now()
}).run(conn)

Read more about this command →

time

r.time(year, month, day[, hour, minute, second], timezone) → time

Create a time object for a specific time.

Example: Update the birthdate of the user “John” to November 3rd, 1986 UTC.

r.table("user").get("John").update(:birthdate => r.time(1986, 11, 3, 'Z')).run(conn)

Read more about this command →

epoch_time

r.epoch_time(number) → time

Create a time object based on seconds since epoch. The first argument is a double and will be rounded to three decimal places (millisecond-precision).

Example: Update the birthdate of the user “John” to November 3rd, 1986.

r.table("user").get("John").update(:birthdate => r.epoch_time(531360000)).run(conn)

Read more about this command →

iso8601

r.iso8601(string[, {default_timezone:''}]) → time

Create a time object based on an ISO 8601 date-time string (e.g. ‘2013-01-01T01:01:01+00:00’). RethinkDB supports all valid ISO 8601 formats except for week dates. Read more about the ISO 8601 format at Wikipedia.

Example: Update the time of John’s birth.

r.table("user").get("John").update(:birth => r.iso8601('1986-11-03T08:30:00-07:00')).run(conn)

Read more about this command →

in_timezone

time.in_timezone(timezone) → time

Return a new time object with a different timezone. While the time stays the same, the results returned by methods such as hours() will change since they take the timezone into account. The timezone argument has to be of the ISO 8601 format.

Example: Hour of the day in San Francisco (UTC/GMT -8, without daylight saving time).

r.now().in_timezone('-08:00').hours().run(conn)

Read more about this command →

timezone

time.timezone() → string

Return the timezone of the time object.

Example: Return all the users in the “-07:00” timezone.

r.table("users").filter{ |user|
    user["subscriptionDate"].timezone().eq("07:00")
}

Read more about this command →

during

time.during(start_time, end_time[, :left_bound => "closed", :right_bound => "open"]) → bool

Return whether a time is between two other times.

Example: Retrieve all the posts that were posted between December 1st, 2013 (inclusive) and December 10th, 2013 (exclusive).

r.table("posts").filter{ |post|
    post['date'].during(r.time(2013, 12, 1, "Z"), r.time(2013, 12, 10, "Z"))
}.run(conn)

Read more about this command →

date

time.date() → time

Return a new time object only based on the day, month and year (ie. the same day at 00:00).

Example: Retrieve all the users whose birthday is today.

r.table("users").filter{ |user|
    user["birthdate"].date() == r.now().date()
}.run(conn)

Read more about this command →

time_of_day

time.time_of_day() → number

Return the number of seconds elapsed since the beginning of the day stored in the time object.

Example: Retrieve posts that were submitted before noon.

r.table("posts").filter{ |post|
    post["date"].time_of_day() <= 12*60*60
}.run(conn)

Read more about this command →

year

time.year() → number

Return the year of a time object.

Example: Retrieve all the users born in 1986.

r.table("users").filter{ |user|
    user["birthdate"].year().eq(1986)
}.run(conn)

Read more about this command →

month

time.month() → number

Return the month of a time object as a number between 1 and 12. For your convenience, the terms r.january, r.february etc. are defined and map to the appropriate integer.

Example: Retrieve all the users who were born in November.

r.table("users").filter{ |user|
    user["birthdate"].month().eq(11)
}

Read more about this command →

day

time.day() → number

Return the day of a time object as a number between 1 and 31.

Example: Return the users born on the 24th of any month.

r.table("users").filter{ |user|
    user["birthdate"].day().eq(24)
}

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day_of_week

time.day_of_week() → number

Return the day of week of a time object as a number between 1 and 7 (following ISO 8601 standard). For your convenience, the terms r.monday, r.tuesday etc. are defined and map to the appropriate integer.

Example: Return today’s day of week.

r.now().day_of_week().run(conn)

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day_of_year

time.day_of_year() → number

Return the day of the year of a time object as a number between 1 and 366 (following ISO 8601 standard).

Example: Retrieve all the users who were born the first day of a year.

r.table("users").filter{ |user|
    user["birthdate"].day_of_year().eq(1)
}

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hours

time.hours() → number

Return the hour in a time object as a number between 0 and 23.

Example: Return all the posts submitted after midnight and before 4am.

r.table("posts").filter{ |post|
    post["date"].hours() < 4
}

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minutes

time.minutes() → number

Return the minute in a time object as a number between 0 and 59.

Example: Return all the posts submitted during the first 10 minutes of every hour.

r.table("posts").filter{ |post|
    post["date"].minutes() < 10
}

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seconds

time.seconds() → number

Return the seconds in a time object as a number between 0 and 59.999 (double precision).

Example: Return the post submitted during the first 30 seconds of every minute.

r.table("posts").filter{ |post|
    post["date"].seconds() < 30
}

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to_iso8601

time.to_iso8601() → string

Convert a time object to a string in ISO 8601 format.

Example: Return the current ISO 8601 time.

> r.now().to_iso8601().run(conn)

"2015-04-20T18:37:52.690+00:00"

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to_epoch_time

time.to_epoch_time() → number

Convert a time object to its epoch time.

Example: Return the current time in seconds since the Unix Epoch with millisecond-precision.

r.now().to_epoch_time()

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Control structures

args

r.args(array) → special

r.args is a special term that’s used to splice an array of arguments into another term. This is useful when you want to call a variadic term such as get_all with a set of arguments produced at runtime.

Example: Get Alice and Bob from the table people.

r.table('people').get_all('Alice', 'Bob').run(conn)
# or
r.table('people').get_all(r.args(['Alice', 'Bob'])).run(conn)

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binary

r.binary(data) → binary

Encapsulate binary data within a query.

Example: Save an avatar image to a existing user record.

f = File.open('./default_avatar.png', 'rb')
avatar_image = f.read()
f.close()
r.table('users').get(100).update({:avatar => r.binary(avatar_image)}).run(conn)

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do

any.do(function) → any

r.do([args]*, function) → any

any.do(expr) → any

r.do([args]*, expr) → any

Call an anonymous function using return values from other ReQL commands or queries as arguments.

Example: Compute a golfer’s net score for a game.

r.table('players').get('f19b5f16-ef14-468f-bd48-e194761df255').do { |player|
    player['gross_score'] - player['course_handicap']
}.run(conn)

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branch

r.branch(test, true_action[, test2, test2_action, ...], false_action) → any

test.branch(true_action[, test2, test2_action, ...], false_action) → any

Perform a branching conditional equivalent to if-then-else.

The branch command takes 2n+1 arguments: pairs of conditional expressions and commands to be executed if the conditionals return any value but false or nil (i.e., “truthy” values), with a final “else” command to be evaluated if all of the conditionals are false or nil.

Example: Test the value of x.

x = 10
r.branch((x > 5), 'big', 'small').run(conn)

> "big"

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for_each

sequence.for_each(write_function) → object

Loop over a sequence, evaluating the given write query for each element.

Example: Now that our heroes have defeated their villains, we can safely remove them from the villain table.

r.table('marvel').for_each {|hero|
    r.table('villains').get(hero[:villain_defeated]).delete
}.run(conn)

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range

r.range() → stream

r.range([start_value, ]end_value) → stream

Generate a stream of sequential integers in a specified range.

Example: Return a four-element range of [0, 1, 2, 3].

> r.range(4).run(conn)

[0, 1, 2, 3]

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error

r.error(message) → error

Throw a runtime error. If called with no arguments inside the second argument to default, re-throw the current error.

Example: Iron Man can’t possibly have lost a battle:

r.table('marvel').get('IronMan').do { |ironman|
    r.branch(ironman[:victories] < ironman[:battles],
    r.error('impossible code path'),
    ironman)
}.run(conn)

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default

value.default(default_value | function) → any

sequence.default(default_value | function) → any

Provide a default value in case of non-existence errors. The default command evaluates its first argument (the value it’s chained to). If that argument returns nil or a non-existence error is thrown in evaluation, then default returns its second argument. The second argument is usually a default value, but it can be a function that returns a value.

Example: Retrieve the titles and authors of the table posts. In the case where the author field is missing or nil, we want to retrieve the string Anonymous.

r.table("posts").map{ |post|
    {
        :title => post[:title],
        :author => post[:author].default("Anonymous")
    }
}.run(conn)

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expr

r.expr(value) → value

Construct a ReQL JSON object from a native object.

Example: Objects wrapped with expr can then be manipulated by ReQL API functions.

r.expr({:a => 'b'}).merge({:b => [1,2,3]}).run(conn)

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js

r.js(js_string[, :timeout => <number>]) → value

Create a javascript expression.

Example: Concatenate two strings using JavaScript.

r.js("'str1' + 'str2'").run(conn)

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coerce_to

sequence.coerce_to('array') → array

value.coerce_to('string') → string

string.coerce_to('number') → number

array.coerce_to('object') → object

sequence.coerce_to('object') → object

object.coerce_to('array') → array

binary.coerce_to('string') → string

string.coerce_to('binary') → binary

Convert a value of one type into another.

Example: Coerce a stream to an array to store its output in a field. (A stream cannot be stored in a field directly.)

r.table('posts').map { |post|
    { :comments => r.table('comments').get_all(post['id'], {:index => 'post_id'}).coerce_to('array') }
}.run(conn)

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type_of

any.type_of() → string

Gets the type of a ReQL query’s return value.

Example: Get the type of a string.

> r.expr("foo").type_of().run(conn)
"STRING"

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info

any.info() → object

r.info(any) → object

Get information about a ReQL value.

Example: Get information about a table such as primary key, or cache size.

r.table('marvel').info().run(conn)

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json

r.json(json_string) → value

Parse a JSON string on the server.

Example: Send an array to the server.

r.json("[1,2,3]").run(conn)

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to_json_string

value.to_json_string() → string

Convert a ReQL value or object to a JSON string.

Example: Get a ReQL document as a JSON string.

> r.table('hero').get(1).to_json_string()

'{"id": 1, "name": "Batman", "city": "Gotham", "powers": ["martial arts", "cinematic entrances"]}'

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http

r.http(url[, options]) → value

r.http(url[, options]) → stream

Retrieve data from the specified URL over HTTP. The return type depends on the result_format option, which checks the Content-Type of the response by default. Make sure that you never use this command for user provided URLs.

Example: Perform an HTTP GET and store the result in a table.

r.table('posts').insert(r.http('http://httpbin.org/get')).run(conn)

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uuid

r.uuid([string]) → string

Return a UUID (universally unique identifier), a string that can be used as a unique ID. If a string is passed to uuid as an argument, the UUID will be deterministic, derived from the string’s SHA-1 hash.

Example: Generate a UUID.

> r.uuid().run(conn)

"27961a0e-f4e8-4eb3-bf95-c5203e1d87b9"

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Geospatial commands

circle

r.circle([longitude, latitude], radius[, {:num_vertices => 32, :geo_system => 'WGS84', :unit => 'm', :fill => true}]) → geometry

r.circle(point, radius[, {:num_vertices => 32, :geo_system => 'WGS84', :unit => 'm', :fill => true}]) → geometry

Construct a circular line or polygon. A circle in RethinkDB is a polygon or line approximating a circle of a given radius around a given center, consisting of a specified number of vertices (default 32).

Example: Define a circle.

r.table('geo').insert({
    :id => 300,
    :name => 'Hayes Valley',
    :neighborhood => r.circle([-122.423246,37.779388], 1000)
}).run(conn)

Read more about this command →

distance

geometry.distance(geometry[, {:geo_system => 'WGS84', :unit => 'm'}]) → number

r.distance(geometry, geometry[, {:geo_system => 'WGS84', :unit => 'm'}]) → number

Compute the distance between a point and another geometry object. At least one of the geometry objects specified must be a point.

Example: Compute the distance between two points on the Earth in kilometers.

> point1 = r.point(-122.423246,37.779388)
> point2 = r.point(-117.220406,32.719464)
> r.distance(point1, point2, {:unit => 'km'}).run(conn)

734.1252496021841

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fill

line.fill() → polygon

Convert a Line object into a Polygon object. If the last point does not specify the same coordinates as the first point, polygon will close the polygon by connecting them.

Example: Create a line object and then convert it to a polygon.

r.table('geo').insert({
    :id => 201,
    :rectangle => r.line(
        [-122.423246,37.779388],
        [-122.423246,37.329898],
        [-121.886420,37.329898],
        [-121.886420,37.779388]
    )
}).run(conn)

r.table('geo').get(201).update(:non_atomic => true){ |doc|
    { :rectangle => doc['rectangle'].fill() }
}.run(conn)

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geojson

r.geojson(geojson) → geometry

Convert a GeoJSON object to a ReQL geometry object.

Example: Convert a GeoJSON object to a ReQL geometry object.

geo_json = {
    :type => 'Point',
    :coordinates => [ -122.423246, 37.779388 ]
}
r.table('geo').insert({
    :id => 'sfo',
    :name => 'San Francisco',
    :location => r.geojson(geo_json)
}).run(conn)

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to_geojson

geometry.to_geojson() → object

Convert a ReQL geometry object to a GeoJSON object.

Example: Convert a ReQL geometry object to a GeoJSON object.

> r.table('geo').get('sfo')['location'].to_geojson.run(conn)

{
    :type => 'Point',
    :coordinates => [ -122.423246, 37.779388 ]
}

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get_intersecting

table.get_intersecting(geometry, {:index => 'indexname'}) → selection<stream>

Get all documents where the given geometry object intersects the geometry object of the requested geospatial index.

Example: Which of the locations in a list of parks intersect circle1?

circle1 = r.circle([-117.220406,32.719464], 10, {:unit => 'mi'})
r.table('parks').get_intersecting(circle1, {:index => 'area'}).run(conn)

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get_nearest

table.get_nearest(point, {:index => 'indexname'[, :max_results => 100, :max_dist => 100000, :unit => 'm', :geo_system => 'WGS84']}) → array

Return a list of documents closest to a specified point based on a geospatial index, sorted in order of increasing distance.

Example: Return a list of the closest 25 enemy hideouts to the secret base.

secret_base = r.point(-122.422876,37.777128)
r.table('hideouts').get_nearest(secret_base, {:index => 'location',
    :max_results => 25}).run(conn)

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includes

sequence.includes(geometry) → sequence

geometry.includes(geometry) → bool

Tests whether a geometry object is completely contained within another. When applied to a sequence of geometry objects, includes acts as a filter, returning a sequence of objects from the sequence that include the argument.

Example: Is point2 included within a 2000-meter circle around point1?

> point1 = r.point(-117.220406,32.719464)
> point2 = r.point(-117.206201,32.725186)
> r.circle(point1, 2000).includes(point2).run(conn)

true

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intersects

sequence.intersects(geometry) → sequence

geometry.intersects(geometry) → bool

r.intersects(sequence, geometry) → sequence

r.intersects(geometry, geometry) → bool

Tests whether two geometry objects intersect with one another. When applied to a sequence of geometry objects, intersects acts as a filter, returning a sequence of objects from the sequence that intersect with the argument.

Example: Is point2 within a 2000-meter circle around point1?

> point1 = r.point(-117.220406,32.719464)
> point2 = r.point(-117.206201,32.725186)
> r.circle(point1, 2000).intersects(point2).run(conn)

true

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line

r.line([lon1, lat1], [lon2, lat2], ...) → line

r.line(point1, point2, ...) → line

Construct a geometry object of type Line. The line can be specified in one of two ways:

  • Two or more two-item arrays, specifying latitude and longitude numbers of the line’s vertices;
  • Two or more Point objects specifying the line’s vertices.

Example: Define a line.

r.table('geo').insert({
    :id => 101,
    :route => r.line([-122.423246,37.779388], [-121.886420,37.329898])
}).run(conn)

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point

r.point(longitude, latitude) → point

Construct a geometry object of type Point. The point is specified by two floating point numbers, the longitude (−180 to 180) and latitude (−90 to 90) of the point on a perfect sphere. See Geospatial support for more information on ReQL’s coordinate system.

Example: Define a point.

r.table('geo').insert({
    :id => 1,
    :name => 'San Francisco',
    :location => r.point(-122.423246,37.779388)
}).run(conn)

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polygon

r.polygon([lon1, lat1], [lon2, lat2], [lon3, lat3], ...) → polygon

r.polygon(point1, point2, point3, ...) → polygon

Construct a geometry object of type Polygon. The Polygon can be specified in one of two ways:

  • Three or more two-item arrays, specifying latitude and longitude numbers of the polygon’s vertices;
  • Three or more Point objects specifying the polygon’s vertices.

Example: Define a polygon.

r.table('geo').insert({
    :id => 101,
    :rectangle => r.polygon(
        [-122.423246,37.779388],
        [-122.423246,37.329898],
        [-121.886420,37.329898],
        [-121.886420,37.779388]
    )
}).run(conn)

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polygon_sub

polygon1.polygon_sub(polygon2) → polygon

Use polygon2 to “punch out” a hole in polygon1. polygon2 must be completely contained within polygon1 and must have no holes itself (it must not be the output of polygon_sub itself).

Example: Define a polygon with a hole punched in it.

outer_polygon = r.polygon(
    [-122.4,37.7],
    [-122.4,37.3],
    [-121.8,37.3],
    [-121.8,37.7]
)
inner_polygon = r.polygon(
    [-122.3,37.4],
    [-122.3,37.6],
    [-122.0,37.6],
    [-122.0,37.4]
)
outer_polygon.polygon_sub(inner_polygon).run(conn)

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Administration

grant

r.grant("username", {:permission => bool[, ...]}) → object

db.grant("username", {:permission => bool[, ...]}) → object

table.grant("username", {:permission => bool[, ...]}) → object

Grant or deny access permissions for a user account, globally or on a per-database or per-table basis.

Example: Grant the chatapp user account read and write permissions on the users database.

> r.db('users').grant('chatapp', {:read => True, :write => true}).run(conn)

{
    :granted => 1,
    :permissions_changes => [
        {
            :new_val => { :read => true, :write => true },
            :old_val => { nil }
        }
    ]

Read more about this command →

config

table.config() → selection<object>

database.config() → selection<object>

Query (read and/or update) the configurations for individual tables or databases.

Example: Get the configuration for the users table.

r.table('users').config().run(conn)

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rebalance

table.rebalance() → object

database.rebalance() → object

Rebalances the shards of a table. When called on a database, all the tables in that database will be rebalanced.

Example: Rebalance a table.

r.table('superheroes').rebalance().run(conn)

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reconfigure

table.reconfigure({:shards => <s>, :replicas => <r>[, :primary_replica_tag => <t>, :dry_run => false, :nonvoting_replica_tags => nil]}) → object

database.reconfigure({:shards => <s>, :replicas => <r>[, :primary_replica_tag => <t>, :dry_run => false, :nonvoting_replica_tags => nil]}) → object

table.reconfigure(:emergency_repair => <option>, :dry_run => false) → object

Reconfigure a table’s sharding and replication.

Example: Reconfigure a table.

r.table('superheroes').reconfigure({:shards => 2, :replicas => 1}).run(conn)

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status

table.status() → selection<object>

Return the status of a table.

Example: Get a table’s status.

r.table_status('superheroes').run(conn)

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wait

table.wait([{:wait_for => 'all_replicas_ready', :timeout => <sec>}]) → object

database.wait([{:wait_for => 'all_replicas_ready', :timeout => <sec>}]) → object

r.wait(table | database, [{:wait_for => 'all_replicas_ready', :timeout => <sec>}]) → object

Wait for a table (or tables) to be ready. A table may be temporarily unavailable after creation, rebalancing or reconfiguring.

Example: Wait on a table to be ready.

> r.table('superheroes').wait().run(conn)

{:ready => 1}

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