Class: ActiveRecord::ConnectionAdapters::TableDefinition
- Inherits:
-
Object
- Object
- ActiveRecord::ConnectionAdapters::TableDefinition
- Includes:
- ColumnMethods
- Defined in:
- lib/active_record/connection_adapters/abstract/schema_definitions.rb
Overview
Represents the schema of an SQL table in an abstract way. This class provides methods for manipulating the schema representation.
Inside migration files, the t
object in create_table is actually of this type:
class SomeMigration < ActiveRecord::Migration[5.0]
def up
create_table :foo do |t|
puts t.class # => "ActiveRecord::ConnectionAdapters::TableDefinition"
end
end
def down
...
end
end
Direct Known Subclasses
MySQL::TableDefinition, PostgreSQL::TableDefinition, SQLite3::TableDefinition
Instance Attribute Summary collapse
-
#as ⇒ Object
readonly
Returns the value of attribute as.
-
#comment ⇒ Object
readonly
Returns the value of attribute comment.
-
#foreign_keys ⇒ Object
readonly
Returns the value of attribute foreign_keys.
-
#if_not_exists ⇒ Object
readonly
Returns the value of attribute if_not_exists.
-
#indexes ⇒ Object
readonly
Returns the value of attribute indexes.
-
#name ⇒ Object
readonly
Returns the value of attribute name.
-
#options ⇒ Object
readonly
Returns the value of attribute options.
-
#temporary ⇒ Object
readonly
Returns the value of attribute temporary.
Instance Method Summary collapse
-
#[](name) ⇒ Object
Returns a ColumnDefinition for the column with name
name
. -
#column(name, type, **options) ⇒ Object
Instantiates a new column for the table.
-
#columns ⇒ Object
Returns an array of ColumnDefinition objects for the columns of the table.
-
#foreign_key(table_name, **options) ⇒ Object
:nodoc:.
-
#index(column_name, options = {}) ⇒ Object
Adds index options to the indexes hash, keyed by column name This is primarily used to track indexes that need to be created after the table.
-
#initialize(conn, name, temporary: false, if_not_exists: false, options: nil, as: nil, comment: nil) ⇒ TableDefinition
constructor
A new instance of TableDefinition.
-
#new_column_definition(name, type, **options) ⇒ Object
:nodoc:.
-
#primary_keys(name = nil) ⇒ Object
:nodoc:.
-
#references(*args, **options) ⇒ Object
(also: #belongs_to)
Adds a reference.
-
#remove_column(name) ⇒ Object
remove the column
name
from the table. -
#timestamps(**options) ⇒ Object
Appends
:datetime
columns:created_at
and:updated_at
to the table.
Methods included from ColumnMethods
Constructor Details
#initialize(conn, name, temporary: false, if_not_exists: false, options: nil, as: nil, comment: nil) ⇒ TableDefinition
Returns a new instance of TableDefinition.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 266 def initialize( conn, name, temporary: false, if_not_exists: false, options: nil, as: nil, comment: nil, ** ) @conn = conn @columns_hash = {} @indexes = [] @foreign_keys = [] @primary_keys = nil @temporary = temporary @if_not_exists = if_not_exists @options = @as = as @name = name @comment = comment end |
Instance Attribute Details
#as ⇒ Object (readonly)
Returns the value of attribute as.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def as @as end |
#comment ⇒ Object (readonly)
Returns the value of attribute comment.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def comment @comment end |
#foreign_keys ⇒ Object (readonly)
Returns the value of attribute foreign_keys.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def foreign_keys @foreign_keys end |
#if_not_exists ⇒ Object (readonly)
Returns the value of attribute if_not_exists.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def if_not_exists @if_not_exists end |
#indexes ⇒ Object (readonly)
Returns the value of attribute indexes.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def indexes @indexes end |
#name ⇒ Object (readonly)
Returns the value of attribute name.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def name @name end |
#options ⇒ Object (readonly)
Returns the value of attribute options.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def @options end |
#temporary ⇒ Object (readonly)
Returns the value of attribute temporary.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 264 def temporary @temporary end |
Instance Method Details
#[](name) ⇒ Object
Returns a ColumnDefinition for the column with name name
.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 298 def [](name) @columns_hash[name.to_s] end |
#column(name, type, **options) ⇒ Object
Instantiates a new column for the table. See connection.add_column for available options.
Additional options are:
-
:index
- Create an index for the column. Can be eithertrue
or an options hash.
This method returns self
.
Examples
# Assuming +td+ is an instance of TableDefinition
td.column(:granted, :boolean, index: true)
Short-hand examples
Instead of calling #column directly, you can also work with the short-hand definitions for the default types. They use the type as the method name instead of as a parameter and allow for multiple columns to be defined in a single statement.
What can be written like this with the regular calls to column:
create_table :products do |t|
t.column :shop_id, :integer
t.column :creator_id, :integer
t.column :item_number, :string
t.column :name, :string, default: "Untitled"
t.column :value, :string, default: "Untitled"
t.column :created_at, :datetime
t.column :updated_at, :datetime
end
add_index :products, :item_number
can also be written as follows using the short-hand:
create_table :products do |t|
t.integer :shop_id, :creator_id
t.string :item_number, index: true
t.string :name, :value, default: "Untitled"
t. null: false
end
There’s a short-hand method for each of the type values declared at the top. And then there’s TableDefinition#timestamps that’ll add created_at
and updated_at
as datetimes.
TableDefinition#references will add an appropriately-named _id column, plus a corresponding _type column if the :polymorphic
option is supplied. If :polymorphic
is a hash of options, these will be used when creating the _type
column. The :index
option will also create an index, similar to calling add_index. So what can be written like this:
create_table :taggings do |t|
t.integer :tag_id, :tagger_id, :taggable_id
t.string :tagger_type
t.string :taggable_type, default: 'Photo'
end
add_index :taggings, :tag_id, name: 'index_taggings_on_tag_id'
add_index :taggings, [:tagger_id, :tagger_type]
Can also be written as follows using references:
create_table :taggings do |t|
t.references :tag, index: { name: 'index_taggings_on_tag_id' }
t.references :tagger, polymorphic: true
t.references :taggable, polymorphic: { default: 'Photo' }, index: false
end
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 369 def column(name, type, **) name = name.to_s type = type.to_sym if type if @columns_hash[name] if @columns_hash[name].primary_key? raise ArgumentError, "you can't redefine the primary key column '#{name}'. To define a custom primary key, pass { id: false } to create_table." else raise ArgumentError, "you can't define an already defined column '#{name}'." end end = .delete(:index) index(name, .is_a?(Hash) ? : {}) if @columns_hash[name] = new_column_definition(name, type, **) self end |
#columns ⇒ Object
Returns an array of ColumnDefinition objects for the columns of the table.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 295 def columns; @columns_hash.values; end |
#foreign_key(table_name, **options) ⇒ Object
:nodoc:
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 401 def foreign_key(table_name, **) # :nodoc: foreign_keys << [table_name, ] end |
#index(column_name, options = {}) ⇒ Object
Adds index options to the indexes hash, keyed by column name This is primarily used to track indexes that need to be created after the table
index(:account_id, name: 'index_projects_on_account_id')
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 397 def index(column_name, = {}) indexes << [column_name, ] end |
#new_column_definition(name, type, **options) ⇒ Object
:nodoc:
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 434 def new_column_definition(name, type, **) # :nodoc: if integer_like_primary_key?(type, ) type = integer_like_primary_key_type(type, ) end type = aliased_types(type.to_s, type) [:primary_key] ||= type == :primary_key [:null] = false if [:primary_key] create_column_definition(name, type, ) end |
#primary_keys(name = nil) ⇒ Object
:nodoc:
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 289 def primary_keys(name = nil) # :nodoc: @primary_keys = PrimaryKeyDefinition.new(name) if name @primary_keys end |
#references(*args, **options) ⇒ Object Also known as: belongs_to
Adds a reference.
t.references(:user)
t.belongs_to(:supplier, foreign_key: true)
t.belongs_to(:supplier, foreign_key: true, type: :integer)
See connection.add_reference for details of the options you can use.
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 427 def references(*args, **) args.each do |ref_name| ReferenceDefinition.new(ref_name, **).add_to(self) end end |
#remove_column(name) ⇒ Object
remove the column name
from the table.
remove_column(:account_id)
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 389 def remove_column(name) @columns_hash.delete name.to_s end |
#timestamps(**options) ⇒ Object
Appends :datetime
columns :created_at
and :updated_at
to the table. See connection.add_timestamps
t. null: false
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# File 'lib/active_record/connection_adapters/abstract/schema_definitions.rb', line 409 def (**) [:null] = false if [:null].nil? if !.key?(:precision) && @conn.supports_datetime_with_precision? [:precision] = 6 end column(:created_at, :datetime, **) column(:updated_at, :datetime, **) end |