Represents a SQL table in an abstract way for updating a table. Also see TableDefinition and ActiveRecord::ConnectionAdapters::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
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Class Public methods
new(table_name, base)
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 566
def initialize(table_name, base)
  @table_name = table_name
  @base = base
end
Instance Public methods
belongs_to(*args)
change(column_name, type, options = {})

Changes the column's definition according to the new options. See ActiveRecord::ConnectionAdapters::TableDefinition#column for details of the options you can use.

Examples
t.change(:name, :string, :limit => 80)
t.change(:description, :text)
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 606
def change(column_name, type, options = {})
  @base.change_column(@table_name, column_name, type, options)
end
change_default(column_name, default)

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

Examples
t.change_default(:qualification, 'new')
t.change_default(:authorized, 1)
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 614
def change_default(column_name, default)
  @base.change_column_default(@table_name, column_name, default)
end
column(column_name, type, options = {})

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

Example
Creating a simple column
t.column(:name, :string)
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 576
def column(column_name, type, options = {})
  @base.add_column(@table_name, column_name, type, options)
end
index(column_name, options = {})

Adds a new index to the table. column_namecan be a single Symbol, or an Array of Symbols. See ActiveRecord::ConnectionAdapters::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')
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 590
def index(column_name, options = {})
  @base.add_index(@table_name, column_name, options)
end
references(*args)

Adds a reference. Optionally adds a typecolumn. referencesand belongs_toare acceptable.

Examples
t.references(:goat)
t.references(:goat, :polymorphic => true)
t.belongs_to(:goat)
Also aliased as: belongs_to
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 661
def references(*args)
  options = args.extract_options!
  polymorphic = options.delete(:polymorphic)
  args.each do |col|
    @base.add_column(@table_name, "#{col}_id", :integer, options)
    @base.add_column(@table_name, "#{col}_type", :string, polymorphic.is_a?(Hash) ? polymorphic : options) unless polymorphic.nil?
  end
end
remove(*column_names)

Removes the column(s) from the table definition.

Examples
t.remove(:qualification)
t.remove(:qualification, :experience)
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 622
def remove(*column_names)
  @base.remove_column(@table_name, column_names)
end
remove_belongs_to(*args)
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
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 637
def remove_index(options = {})
  @base.remove_index(@table_name, options)
end
remove_references(*args)

Removes a reference. Optionally removes a typecolumn. remove_referencesand remove_belongs_toare acceptable.

Examples
t.remove_references(:goat)
t.remove_references(:goat, :polymorphic => true)
t.remove_belongs_to(:goat)
Also aliased as: remove_belongs_to
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 677
def remove_references(*args)
  options = args.extract_options!
  polymorphic = options.delete(:polymorphic)
  args.each do |col|
    @base.remove_column(@table_name, "#{col}_id")
    @base.remove_column(@table_name, "#{col}_type") unless polymorphic.nil?
  end
end
remove_timestamps()

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

Example
t.remove_timestamps
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 644
def remove_timestamps
  @base.remove_timestamps(@table_name)
end
rename(column_name, new_column_name)

Renames a column.

Example
t.rename(:description, :name)
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 651
def rename(column_name, new_column_name)
  @base.rename_column(@table_name, column_name, new_column_name)
end
timestamps()

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

Example
t.timestamps
# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 597
def timestamps
  @base.add_timestamps(@table_name)
end