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 a table an array of 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.
Set the Database object to which to apply the DDL, and evaluate the block in the context of this object.
# File lib/sequel/database/schema_generator.rb, line 219 def initialize(db, &block) @db = db @operations = [] instance_eval(&block) if block end
Add a column with the given name, type, and opts to the DDL for the table. See Generator#column for the available options.
# File lib/sequel/database/schema_generator.rb, line 227 def add_column(name, type, opts = {}) @operations << {:op => :add_column, :name => name, :type => type}.merge(opts) end
Add a constraint with the given name and args to the DDL for the table. See Generator#constraint.
# File lib/sequel/database/schema_generator.rb, line 233 def add_constraint(name, *args, &block) @operations << {:op => :add_constraint, :name => name, :type => :check, :check => block || args} 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 an existing column use the composite key syntax even if it is only one column.
# File lib/sequel/database/schema_generator.rb, line 251 def add_foreign_key(name, table, opts = {}) return add_composite_foreign_key(name, table, opts) if name.is_a?(Array) add_column(name, Integer, {:table=>table}.merge(opts)) 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 258 def add_full_text_index(columns, opts = {}) add_index(columns, {:type=>:full_text}.merge(opts)) end
Add an 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 264 def add_index(columns, opts = {}) @operations << {:op => :add_index, :columns => Array(columns)}.merge(opts) end
Add a primary key to the DDL for the table. See Generator#column for the available options.
# File lib/sequel/database/schema_generator.rb, line 270 def add_primary_key(name, opts = {}) return add_composite_primary_key(name, opts) if name.is_a?(Array) opts = @db.serial_primary_key_options.merge(opts) add_column(name, opts.delete(:type), opts) 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 278 def add_spatial_index(columns, opts = {}) add_index(columns, {:type=>:spatial}.merge(opts)) end
Add a unique constraint to the given column(s)
# File lib/sequel/database/schema_generator.rb, line 238 def add_unique_constraint(columns, opts = {}) @operations << {:op => :add_constraint, :type => :unique, :columns => Array(columns)}.merge(opts) end
Remove a column from the DDL for the table.
# File lib/sequel/database/schema_generator.rb, line 283 def drop_column(name) @operations << {:op => :drop_column, :name => name} end
Remove a constraint from the DDL for the table.
# File lib/sequel/database/schema_generator.rb, line 288 def drop_constraint(name) @operations << {:op => :drop_constraint, :name => name} end
Remove an index from the DDL for the table.
# File lib/sequel/database/schema_generator.rb, line 293 def drop_index(columns, options={}) @operations << {:op => :drop_index, :columns => Array(columns)}.merge(options) end
Modify a column’s name in the DDL for the table.
# File lib/sequel/database/schema_generator.rb, line 298 def rename_column(name, new_name, opts = {}) @operations << {:op => :rename_column, :name => name, :new_name => new_name}.merge(opts) end
Modify a column’s NOT NULL constraint.
# File lib/sequel/database/schema_generator.rb, line 313 def set_column_allow_null(name, allow_null) @operations << {:op => :set_column_null, :name => name, :null => allow_null} end
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