Class: ActiveRecord::ConnectionAdapters::Table

Inherits:
Object
  • Object
show all
Defined in:
activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

Overview

Represents an 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

Instance Method Summary (collapse)

Constructor Details

- (Table) initialize(table_name, base)

Returns a new instance of Table



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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 573

def initialize(table_name, base)
  @table_name = table_name
  @base = base
end

Instance Method Details

- (Object) 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)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 623

def change(column_name, type, options = {})
  @base.change_column(@table_name, column_name, type, options)
end

- (Object) 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)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 631

def change_default(column_name, default)
  @base.change_column_default(@table_name, column_name, default)
end

- (Object) 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)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 583

def column(column_name, type, options = {})
  @base.add_column(@table_name, column_name, type, options)
end

- (Boolean) column_exists?(column_name, type = nil, options = nil)

Checks to see if a column exists. See SchemaStatements#column_exists?

Returns:

  • (Boolean)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 588

def column_exists?(column_name, type = nil, options = nil)
  @base.column_exists?(@table_name, column_name, type, options)
end

- (Object) 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')


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 602

def index(column_name, options = {})
  @base.add_index(@table_name, column_name, options)
end

- (Boolean) index_exists?(column_name, options = {})

Checks to see if an index exists. See SchemaStatements#index_exists?

Returns:

  • (Boolean)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 607

def index_exists?(column_name, options = {})
  @base.index_exists?(@table_name, column_name, options)
end

- (Object) references(*args) Also known as: belongs_to

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)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 678

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

- (Object) remove(*column_names)

Removes the column(s) from the table definition.

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


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 639

def remove(*column_names)
  @base.remove_column(@table_name, column_names)
end

- (Object) 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


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 654

def remove_index(options = {})
  @base.remove_index(@table_name, options)
end

- (Object) remove_references(*args) Also known as: remove_belongs_to

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)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 694

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

- (Object) remove_timestamps

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

Example
t.remove_timestamps


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 661

def remove_timestamps
  @base.remove_timestamps(@table_name)
end

- (Object) rename(column_name, new_column_name)

Renames a column.

Example
t.rename(:description, :name)


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 668

def rename(column_name, new_column_name)
  @base.rename_column(@table_name, column_name, new_column_name)
end

- (Object) timestamps

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

Example
t.timestamps


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 614

def timestamps
  @base.add_timestamps(@table_name)
end