Class | Sequel::Schema::AlterTableGenerator |
In: |
lib/sequel/database/schema_generator.rb
|
Parent: | Object |
Schema::AlterTableGenerator is an internal class that the user is not expected to instantiate directly. Instances are created by Database#alter_table. It is used to specify table alteration parameters. It takes a Database object and a block of operations to perform on the table, and gives the Database an array of table altering operations, which the database uses to alter a table‘s description.
For more information on Sequel‘s support for schema modification, see the "Migrations and Schema Modification" guide.
operations | [R] | An array of DDL operations to perform |
Add a column with the given name, type, and opts to the DDL for the table. See Generator#column for the available options.
add_column(:name, String) # ADD COLUMN name varchar(255)
# File lib/sequel/database/schema_generator.rb, line 259 259: def add_column(name, type, opts = {}) 260: @operations << {:op => :add_column, :name => name, :type => type}.merge(opts) 261: end
Add a constraint with the given name and args to the DDL for the table. See Generator#constraint.
add_constraint(:valid_name, :name.like('A%')) # ADD CONSTRAINT valid_name CHECK (name LIKE 'A%')
# File lib/sequel/database/schema_generator.rb, line 268 268: def add_constraint(name, *args, &block) 269: @operations << {:op => :add_constraint, :name => name, :type => :check, :check => block || args} 270: end
Add a foreign key with the given name and referencing the given table to the DDL for the table. See Generator#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 exists and will only add 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
# File lib/sequel/database/schema_generator.rb, line 292 292: def add_foreign_key(name, table, opts = {}) 293: return add_composite_foreign_key(name, table, opts) if name.is_a?(Array) 294: add_column(name, Integer, {:table=>table}.merge(opts)) 295: end
Add a full text index on the given columns to the DDL for the table. See Generator#index for available options.
# File lib/sequel/database/schema_generator.rb, line 299 299: def add_full_text_index(columns, opts = {}) 300: add_index(columns, {:type=>:full_text}.merge(opts)) 301: end
Add an index on the given columns to the DDL for the table. See Generator#index for available options.
add_index(:artist_id) # CREATE INDEX table_artist_id_index ON table (artist_id)
# File lib/sequel/database/schema_generator.rb, line 307 307: def add_index(columns, opts = {}) 308: @operations << {:op => :add_index, :columns => Array(columns)}.merge(opts) 309: end
Add a primary key to the DDL for the table. See Generator#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)
# File lib/sequel/database/schema_generator.rb, line 317 317: def add_primary_key(name, opts = {}) 318: return add_composite_primary_key(name, opts) if name.is_a?(Array) 319: opts = @db.serial_primary_key_options.merge(opts) 320: add_column(name, opts.delete(:type), opts) 321: end
Add a spatial index on the given columns to the DDL for the table. See Generator#index for available options.
# File lib/sequel/database/schema_generator.rb, line 325 325: def add_spatial_index(columns, opts = {}) 326: add_index(columns, {:type=>:spatial}.merge(opts)) 327: end
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)
# File lib/sequel/database/schema_generator.rb, line 276 276: def add_unique_constraint(columns, opts = {}) 277: @operations << {:op => :add_constraint, :type => :unique, :columns => Array(columns)}.merge(opts) 278: end
Remove a column from the DDL for the table.
drop_column(:artist_id) # DROP COLUMN artist_id
# File lib/sequel/database/schema_generator.rb, line 332 332: def drop_column(name) 333: @operations << {:op => :drop_column, :name => name} 334: end
Remove a constraint from the DDL for the table.
drop_constraint(:unique_name) # DROP CONSTRAINT unique_name
# File lib/sequel/database/schema_generator.rb, line 339 339: def drop_constraint(name) 340: @operations << {:op => :drop_constraint, :name => name} 341: end
Remove an index from the DDL for the table.
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
# File lib/sequel/database/schema_generator.rb, line 348 348: def drop_index(columns, options={}) 349: @operations << {:op => :drop_index, :columns => Array(columns)}.merge(options) 350: end
Modify a column‘s name in the DDL for the table.
rename_column(:name, :artist_name) # RENAME COLUMN name TO artist_name
# File lib/sequel/database/schema_generator.rb, line 355 355: def rename_column(name, new_name, opts = {}) 356: @operations << {:op => :rename_column, :name => name, :new_name => new_name}.merge(opts) 357: end
Modify a column‘s NOT NULL constraint.
set_column_allow_null(:artist_name, false) # ALTER COLUMN artist_name SET NOT NULL
# File lib/sequel/database/schema_generator.rb, line 376 376: def set_column_allow_null(name, allow_null) 377: @operations << {:op => :set_column_null, :name => name, :null => allow_null} 378: end
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'
# File lib/sequel/database/schema_generator.rb, line 362 362: def set_column_default(name, default) 363: @operations << {:op => :set_column_default, :name => name, :default => default} 364: end
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)
# File lib/sequel/database/schema_generator.rb, line 369 369: def set_column_type(name, type, opts={}) 370: @operations << {:op => :set_column_type, :name => name, :type => type}.merge(opts) 371: end