Indexing¶

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Creating Indexes
Dropping Indexes
Listing Indexes

The driver provides the ability to create, drop and view indexes on a collection.

Creating Indexes¶

Indexes can be created one at a time, or several can be created in a single operation. When creating multiple indexes on MongoDB 3.0 and later, the indexes are created in parallel. On earlier versions they are created in order.

To create a single index, use create_one.

copy

client = Mongo::Client.new([ '127.0.0.1:27017' ], :database => 'music')
client[:bands].indexes.create_one( { :name => 1 }, unique: true )

To create multiple indexes, use create_many. Note that when creating many, the index keys must be passed as a key value in the provided spec. This is due to the fact that options can be different for each index being created.

copy

client = Mongo::Client.new([ '127.0.0.1:27017' ], :database => 'music')
client[:bands].indexes.create_many([
  { :key => { name: 1 }, unique: true },
  { :key => { label: -1 } }
])

The following is a full list of the available options that can be added when creating indexes.

Option	Description
`:background`	Either `true` or `false`. Tells the index to be created in the background.
`:expire_after`	Number of seconds to expire documents in the collection after.
`:name`	The name of the index.
`:sparse`	Whether the index should be sparse or not, either `true` or `false`.
`:storage_engine`	The name of the storage engine for this particular index.
`:version`	The index format version to use.
`:default_language`	The default language of text indexes.
`:language_override`	The field name to use when overriding the default language.
`:text_version`	The version format for text index storage.
`:weights`	A document specifying fields and weights in text search.
`:sphere_version`	The 2d sphere index version.
`:bits`	Sets the maximum boundary for latitude and longitude in the 2d index.
`:max`	Maximum boundary for latitude and longitude in the 2d index.
`:min`	Minimum boundary for latitude and longitude in the 2d index.
`:bucket_size`	The number of units within which to group the location values in a geo haystack index.
`:partial_filter_expression`	A filter for a partial index.

Dropping Indexes¶

To drop an index, call dropOne or dropAll.

copy

client = Mongo::Client.new([ '127.0.0.1:27017' ], :database => 'music')

client[:bands].indexes.drop_one( 'name_1' ) # Drops the name_1 index.
client[:bands].indexes.drop_all # Drops all indexes in the collection.

Listing Indexes¶

copy

client = Mongo::Client.new([ '127.0.0.1:27017' ], :database => 'music')

client[:bands].indexes.each do |index|
  p index
end

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