createIndex() – Create one or more indexes on a collection command

indexSpec

Required and optional arguments for use in creating the index:

field

• Required
• Specifies a field in the document on which the index is to be created.
• Can include a data type definition.

sortorder

• Optional
• Possible values: 1 | -1
• If the argument is set to 1, order is ascending. This is the default setting.
• If the argument is set to -1, order is descending.

indexName

• Required
• Specifies a name for an index.
• If no value is specified for indexName, a name is generated.

expireAfterSeconds

• Optional
• Specifies a value, in seconds, at which point the documents in the specified collection are deleted

expireAt

• Optional
• Specifies an expiration date/time for the operation.

unique

• Optional.
• Specifies whether the index is unique.
• Possible values: true | false

indexOption

name

• Required.
• The name of the index, specified by indexName.
• If no value is specified for name, a name is generated.

array

• Required.
• Specifies whether array elements are allowed in the index.
• Possible values: true | false.
• Default value: false

unique

• Required.
• Specifies whether the index is unique on the collection.
• Possible values: true | false.
• Default value: false

The following example shows the command syntax for creating an index on the field, author, in ascending order, by using the default type string with a default length of 50, from the collection, books:

db.books.createIndex({"author": 1})

The following example shows the successful output from running the createIndex operation on the field, author:

Index <books_xauthor> was created successfully.

The following example shows the command syntax for creating an index on the field, category, with a type value of string and a field length of 40:

db.books.createIndex({"category": [1, "$string", 40]})

The following example shows the successful output from running the createIndex command on the field category:

Index <books_xcategory> was created successfully.

The following example shows the command syntax for creating an index on the field price, with the type value in descending order, and a name value of mypriceidx.

db.books.createIndex({"price": [-1, "$number"]}, “mypriceidx”)

The following example shows the successful output from running the createIndex command on the field price:

Index <mypriceidx> was created successfully.