Represents a SQL table in an abstract way for updating a table. Also see TableDefinition and SchemaStatements#create_table

Available transformations are: 

  change_table :table do |t|
    t.column
    t.index
    t.timestamps
    t.change
    t.change_default
    t.rename
    t.references
    t.belongs_to
    t.string
    t.text
    t.integer
    t.float
    t.decimal
    t.datetime
    t.timestamp
    t.time
    t.date
    t.binary
    t.boolean
    t.remove
    t.remove_references
    t.remove_belongs_to
    t.remove_index
    t.remove_timestamps
  end
Methods
Public Class methods
new(table_name, base)

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 509
509:       def initialize(table_name, base)
510:         @table_name = table_name
511:         @base = base
512:       end
Public Instance methods
belongs_to(*args)

Alias for references

change(column_name, type, options = {})

Changes the column‘s definition according to the new options. See TableDefinition#column for details of the options you can use.

Examples
 t.change(:name, :string, :limit => 80)
 t.change(:description, :text)

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 549
549:       def change(column_name, type, options = {})
550:         @base.change_column(@table_name, column_name, type, options)
551:       end
change_default(column_name, default)

Sets a new default value for a column. See SchemaStatements#change_column_default

Examples
 t.change_default(:qualification, 'new')
 t.change_default(:authorized, 1)

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 557
557:       def change_default(column_name, default)
558:         @base.change_column_default(@table_name, column_name, default)
559:       end
column(column_name, type, options = {})

Adds a new column to the named table. See TableDefinition#column for details of the options you can use.

Example
Creating a simple column
 t.column(:name, :string)

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 519
519:       def column(column_name, type, options = {})
520:         @base.add_column(@table_name, column_name, type, options)
521:       end
index(column_name, options = {})

Adds a new index to the table. column_name can be a single Symbol, or an Array of Symbols. See SchemaStatements#add_index

Examples
Creating a simple index
 t.index(:name)
Creating a unique index
 t.index([:branch_id, :party_id], :unique => true)
Creating a named index
 t.index([:branch_id, :party_id], :unique => true, :name => 'by_branch_party')

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 533
533:       def index(column_name, options = {})
534:         @base.add_index(@table_name, column_name, options)
535:       end
references(*args)

Adds a reference. Optionally adds a type column. references and belongs_to are acceptable.

Examples
 t.references(:goat)
 t.references(:goat, :polymorphic => true)
 t.belongs_to(:goat)
This method is also aliased as belongs_to

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 604
604:       def references(*args)
605:         options = args.extract_options!
606:         polymorphic = options.delete(:polymorphic)
607:         args.each do |col|
608:           @base.add_column(@table_name, "#{col}_id", :integer, options)
609:           @base.add_column(@table_name, "#{col}_type", :string, polymorphic.is_a?(Hash) ? polymorphic : options) unless polymorphic.nil?
610:         end
611:       end
remove(*column_names)

Removes the column(s) from the table definition.

Examples
 t.remove(:qualification)
 t.remove(:qualification, :experience)

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 565
565:       def remove(*column_names)
566:         @base.remove_column(@table_name, column_names)
567:       end
remove_belongs_to(*args)

Alias for remove_references

remove_index(options = {})

Removes the given index from the table.

Examples
Remove the suppliers_name_index in the suppliers table
  t.remove_index :name
Remove the index named accounts_branch_id_index in the accounts table
  t.remove_index :column => :branch_id
Remove the index named accounts_branch_id_party_id_index in the accounts table
  t.remove_index :column => [:branch_id, :party_id]
Remove the index named by_branch_party in the accounts table
  t.remove_index :name => :by_branch_party

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 580
580:       def remove_index(options = {})
581:         @base.remove_index(@table_name, options)
582:       end
remove_references(*args)

Removes a reference. Optionally removes a type column. remove_references and remove_belongs_to are acceptable.

Examples
 t.remove_references(:goat)
 t.remove_references(:goat, :polymorphic => true)
 t.remove_belongs_to(:goat)
This method is also aliased as remove_belongs_to

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 620
620:       def remove_references(*args)
621:         options = args.extract_options!
622:         polymorphic = options.delete(:polymorphic)
623:         args.each do |col|
624:           @base.remove_column(@table_name, "#{col}_id")
625:           @base.remove_column(@table_name, "#{col}_type") unless polymorphic.nil?
626:         end
627:       end
remove_timestamps()

Removes the timestamp columns (created_at and updated_at) from the table.

Example
 t.remove_timestamps

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 587
587:       def remove_timestamps
588:         @base.remove_timestamps(@table_name)
589:       end
rename(column_name, new_column_name)

Renames a column.

Example
 t.rename(:description, :name)

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 594
594:       def rename(column_name, new_column_name)
595:         @base.rename_column(@table_name, column_name, new_column_name)
596:       end
timestamps()

Adds timestamps (created_at and updated_at) columns to the table. See SchemaStatements#add_timestamps

Example
 t.timestamps

[ show source ]

     # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 540
540:       def timestamps
541:         @base.add_timestamps(@table_name)
542:       end