addIndex()

Signature

addIndex() — returns void

Available in: migration Category: Migration Functions

Description

Adds a database index on one or more columns of a table. Indexes speed up queries that filter, sort, or join on those columns. This function is only available inside a migration CFC and is part of the Wheels migrator API.

Parameters

Name	Type	Required	Default	Description
table	string	yes	—	The table name to perform the index operation on
columnNames	string	no	—	One or more column names to index, comma separated
unique	boolean	no	false	If true will create a unique index constraint
indexName	string	no	[runtime expression]	The name of the index to add: Defaults to table name + underscore + first column name

Examples

1. Add a unique index on a single column
addIndex(
    table="members",
    columnNames="username",
    unique=true
);

Ensures username values in members are unique.

2. Add a non-unique index for faster queries
addIndex(
    table="orders",
    columnNames="createdAt"
);

Speeds up queries filtering or ordering by createdAt.

3. Add a composite index (multiple columns)
addIndex(
    table="posts",
    columnNames="authorId,createdAt"
);

Optimizes queries that filter or sort on both authorId and createdAt.

4. Add an index with a custom name
addIndex(
    table="comments",
    columnNames="postId",
    indexName="idx_comments_postId"
);

Creates index with a custom name instead of default comments_postId.

5. Composite unique index
addIndex(
    table="enrollments",
    columnNames="studentId,courseId",
    unique=true,
    indexName="unique_enrollments"
);

Prevents the same studentId and courseId pair from being inserted more than once.