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 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.

### Methods

add_column add_constraint add_foreign_key add_full_text_index add_index add_primary_key add_spatial_index add_unique_constraint drop_column drop_constraint drop_index new rename_column set_column_allow_null set_column_default set_column_type

### Attributes

operations | [R] | An array of DDL operations to perform

### Public Class methods

new(db, &block)

Set the Database object to which to apply the DDL, and evaluate the block in the context of this object.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 219
    219:       def initialize(db, &block)
    220:         @db = db
    221:         @operations = []
    222:         instance_eval(&block) if block
    223:       end

### Public Instance methods

add_column(name, type, opts = {})

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 227
    227:       def add_column(name, type, opts = {})
    228:         @operations << {:op => :add_column, :name => name, :type => type}.merge(opts)
    229:       end

add_constraint(name, *args, &block)

Add a constraint with the given name and args to the DDL for the table. See Generator#constraint.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 233
    233:       def add_constraint(name, *args, &block)
    234:         @operations << {:op => :add_constraint, :name => name, :type => :check, :check => block || args}
    235:       end

add_foreign_key(name, table, opts = {})

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.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 251
    251:       def add_foreign_key(name, table, opts = {})
    252:         return add_composite_foreign_key(name, table, opts) if name.is_a?(Array)
    253:         add_column(name, Integer, {:table=>table}.merge(opts))
    254:       end

add_full_text_index(columns, opts = {})

Add a full text index on the given columns to the DDL for the table. See Generator#index for available options.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 258
    258:       def add_full_text_index(columns, opts = {})
    259:         add_index(columns, {:type=>:full_text}.merge(opts))
    260:       end

add_index(columns, opts = {})

Add an index on the given columns to the DDL for the table. See Generator#index for available options.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 264
    264:       def add_index(columns, opts = {})
    265:         @operations << {:op => :add_index, :columns => Array(columns)}.merge(opts)
    266:       end

add_primary_key(name, opts = {})

Add a primary key to the DDL for the table. See Generator#column for the available options.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 270
    270:       def add_primary_key(name, opts = {})
    271:         return add_composite_primary_key(name, opts) if name.is_a?(Array)
    272:         opts = @db.serial_primary_key_options.merge(opts)
    273:         add_column(name, opts.delete(:type), opts)
    274:       end

add_spatial_index(columns, opts = {})

Add a spatial index on the given columns to the DDL for the table. See Generator#index for available options.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 278
    278:       def add_spatial_index(columns, opts = {})
    279:         add_index(columns, {:type=>:spatial}.merge(opts))
    280:       end

add_unique_constraint(columns, opts = {})

Add a unique constraint to the given column(s)

[Source]

         # File lib/sequel/database/schema_generator.rb, line 238
    238:       def add_unique_constraint(columns, opts = {})
    239:         @operations << {:op => :add_constraint, :type => :unique, :columns => Array(columns)}.merge(opts)
    240:       end

drop_column(name)

Remove a column from the DDL for the table.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 283
    283:       def drop_column(name)
    284:         @operations << {:op => :drop_column, :name => name}
    285:       end

drop_constraint(name)

Remove a constraint from the DDL for the table.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 288
    288:       def drop_constraint(name)
    289:         @operations << {:op => :drop_constraint, :name => name}
    290:       end

drop_index(columns, options={})

Remove an index from the DDL for the table.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 293
    293:       def drop_index(columns, options={})
    294:         @operations << {:op => :drop_index, :columns => Array(columns)}.merge(options)
    295:       end

rename_column(name, new_name, opts = {})

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 298
    298:       def rename_column(name, new_name, opts = {})
    299:         @operations << {:op => :rename_column, :name => name, :new_name => new_name}.merge(opts)
    300:       end

set_column_allow_null(name, allow_null)

Modify a column‘s NOT NULL constraint.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 313
    313:       def set_column_allow_null(name, allow_null)
    314:         @operations << {:op => :set_column_null, :name => name, :null => allow_null}
    315:       end

set_column_default(name, default)

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 303
    303:       def set_column_default(name, default)
    304:         @operations << {:op => :set_column_default, :name => name, :default => default}
    305:       end

set_column_type(name, type, opts={})

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 308
    308:       def set_column_type(name, type, opts={})
    309:         @operations << {:op => :set_column_type, :name => name, :type => type}.merge(opts)
    310:       end

[Validate]