class Sequel::Schema::AlterTableGenerator

Add a column with the given name, type, and opts to the DDL for the table. See Sequel::Schema::CreateTableGenerator#column for the available options.

add_column(:name, String) # ADD COLUMN name varchar(255)

Add a constraint with the given name and args to the DDL for the table. See Sequel::Schema::CreateTableGenerator#constraint.

add_constraint(:valid_name, Sequel.like(:name, 'A%'))
# ADD CONSTRAINT valid_name CHECK (name LIKE 'A%')
add_constraint({:name=>:valid_name, :deferrable=>true}, :num=>1..5)
# CONSTRAINT valid_name CHECK (name LIKE 'A%') DEFERRABLE INITIALLY DEFERRED

Add a foreign key with the given name and referencing the given table to the DDL for the table. See Sequel::Schema::CreateTableGenerator#column for the available options.

You can also pass an array of column names for creating composite foreign keys. In this case, it will assume the columns exist and will only add the constraint. You can provide a :name option to name the constraint.

NOTE: If you need to add a foreign key constraint to a single existing column use the composite key syntax even if it is only one column.

add_foreign_key(:artist_id, :table) # ADD COLUMN artist_id integer REFERENCES table
add_foreign_key([:name], :table) # ADD FOREIGN KEY (name) REFERENCES table

PostgreSQL specific options:

:not_valid

Set to true to add the constraint with the NOT VALID syntax. This makes it so that future inserts must respect referential integrity, but allows the constraint to be added even if existing column values reference rows that do not exist. After all the existing data has been cleaned up, validate_constraint can be used to mark the constraint as valid. Note that this option only makes sense when using an array of columns.

Add a full text index on the given columns to the DDL for the table. See Sequel::Schema::CreateTableGenerator#index for available options.

Add an index on the given columns to the DDL for the table. See Sequel::Schema::CreateTableGenerator#index for available options.

add_index(:artist_id) # CREATE INDEX table_artist_id_index ON table (artist_id)

Add a primary key to the DDL for the table. See Sequel::Schema::CreateTableGenerator#column for the available options. Like add_foreign_key, if you specify the column name as an array, it just creates a constraint:

add_primary_key(:id) # ADD COLUMN id serial PRIMARY KEY
add_primary_key([:artist_id, :name]) # ADD PRIMARY KEY (artist_id, name)

Add a spatial index on the given columns to the DDL for the table. See Sequel::Schema::CreateTableGenerator#index for available options.

Add a unique constraint to the given column(s)

add_unique_constraint(:name) # ADD UNIQUE (name)
add_unique_constraint(:name, :name=>:unique_name) # ADD CONSTRAINT unique_name UNIQUE (name)

Supports the same :deferrable option as Sequel::Schema::CreateTableGenerator#column.

Remove a column from the DDL for the table.

drop_column(:artist_id) # DROP COLUMN artist_id
drop_column(:artist_id, :cascade=>true) # DROP COLUMN artist_id CASCADE

Remove a constraint from the DDL for the table. MySQL/SQLite specific options:

:type

Set the type of constraint to drop, either :primary_key, :foreign_key, or :unique.

drop_constraint(:unique_name) # DROP CONSTRAINT unique_name
drop_constraint(:unique_name, :cascade=>true) # DROP CONSTRAINT unique_name CASCADE

Remove a foreign key and the associated column from the DDL for the table. General options:

:name

The name of the constraint to drop. If not given, uses the same name that would be used by #add_foreign_key with the same columns.

NOTE: If you want to drop only the foreign key constraint but keep the column, use the composite key syntax even if it is only one column.

drop_foreign_key(:artist_id) # DROP CONSTRAINT table_artist_id_fkey, DROP COLUMN artist_id
drop_foreign_key([:name]) # DROP CONSTRAINT table_name_fkey

Remove an index from the DDL for the table. General options:

:name

The name of the index to drop. If not given, uses the same name that would be used by #add_index with the same columns.

PostgreSQL specific options:

:cascade

Cascade the index drop to dependent objects.

:concurrently

Drop the index using CONCURRENTLY, which doesn’t block operations on the table. Supported in PostgreSQL 9.2+.

:if_exists

Only drop the index if it already exists.

drop_index(:artist_id) # DROP INDEX table_artist_id_index
drop_index([:a, :b]) # DROP INDEX table_a_b_index
drop_index([:a, :b], :name=>:foo) # DROP INDEX foo

Modify a column’s name in the DDL for the table.

rename_column(:name, :artist_name) # RENAME COLUMN name TO artist_name

Set a given column as allowing NULL values.

set_column_allow_null(:artist_name) # ALTER COLUMN artist_name DROP NOT NULL

Modify a column’s default value in the DDL for the table.

set_column_default(:artist_name, 'a') # ALTER COLUMN artist_name SET DEFAULT 'a'

Set a given column as not allowing NULL values.

set_column_not_null(:artist_name) # ALTER COLUMN artist_name SET NOT NULL

Modify a column’s type in the DDL for the table.

set_column_type(:artist_name, 'char(10)') # ALTER COLUMN artist_name TYPE char(10)

PostgreSQL specific options:

:using

Add a USING clause that specifies how to convert existing values to new values.