require 'active_record/migration/join_table' require 'active_support/core_ext/string/access' require 'digest' module ActiveRecord module ConnectionAdapters # :nodoc: module SchemaStatements include ActiveRecord::Migration::JoinTable # Returns a hash of mappings from the abstract data types to the native # database types. See TableDefinition#column for details on the recognized # abstract data types. def native_database_types {} end def table_options(table_name) nil end # Returns the table comment that's stored in database metadata. def table_comment(table_name) nil end # Truncates a table alias according to the limits of the current adapter. def table_alias_for(table_name) table_name[0...table_alias_length].tr('.', '_') end # Returns the relation names useable to back Active Record models. # For most adapters this means all #tables and #views. def data_sources tables | views end # Checks to see if the data source +name+ exists on the database. # # data_source_exists?(:ebooks) # def data_source_exists?(name) data_sources.include?(name.to_s) end # Returns an array of table names defined in the database. def tables(name = nil) raise NotImplementedError, "#tables is not implemented" end # Checks to see if the table +table_name+ exists on the database. # # table_exists?(:developers) # def table_exists?(table_name) tables.include?(table_name.to_s) end # Returns an array of view names defined in the database. def views raise NotImplementedError, "#views is not implemented" end # Checks to see if the view +view_name+ exists on the database. # # view_exists?(:ebooks) # def view_exists?(view_name) views.include?(view_name.to_s) end # Returns an array of indexes for the given table. # def indexes(table_name, name = nil) end # Checks to see if an index exists on a table for a given index definition. # # # Check an index exists # index_exists?(:suppliers, :company_id) # # # Check an index on multiple columns exists # index_exists?(:suppliers, [:company_id, :company_type]) # # # Check a unique index exists # index_exists?(:suppliers, :company_id, unique: true) # # # Check an index with a custom name exists # index_exists?(:suppliers, :company_id, name: "idx_company_id") # def index_exists?(table_name, column_name, options = {}) column_names = Array(column_name).map(&:to_s) checks = [] checks << lambda { |i| i.columns == column_names } checks << lambda { |i| i.unique } if options[:unique] checks << lambda { |i| i.name == options[:name].to_s } if options[:name] indexes(table_name).any? { |i| checks.all? { |check| check[i] } } end # Returns an array of Column objects for the table specified by +table_name+. # See the concrete implementation for details on the expected parameter values. def columns(table_name) raise NotImplementedError, "#columns is not implemented" end # Checks to see if a column exists in a given table. # # # Check a column exists # column_exists?(:suppliers, :name) # # # Check a column exists of a particular type # column_exists?(:suppliers, :name, :string) # # # Check a column exists with a specific definition # column_exists?(:suppliers, :name, :string, limit: 100) # column_exists?(:suppliers, :name, :string, default: 'default') # column_exists?(:suppliers, :name, :string, null: false) # column_exists?(:suppliers, :tax, :decimal, precision: 8, scale: 2) # def column_exists?(table_name, column_name, type = nil, options = {}) column_name = column_name.to_s checks = [] checks << lambda { |c| c.name == column_name } checks << lambda { |c| c.type == type } if type (migration_keys - [:name]).each do |attr| checks << lambda { |c| c.send(attr) == options[attr] } if options.key?(attr) end columns(table_name).any? { |c| checks.all? { |check| check[c] } } end # Returns just a table's primary key def primary_key(table_name) pk = primary_keys(table_name) pk = pk.first unless pk.size > 1 pk end # Creates a new table with the name +table_name+. +table_name+ may either # be a String or a Symbol. # # There are two ways to work with #create_table. You can use the block # form or the regular form, like this: # # === Block form # # # create_table() passes a TableDefinition object to the block. # # This form will not only create the table, but also columns for the # # table. # # create_table(:suppliers) do |t| # t.column :name, :string, limit: 60 # # Other fields here # end # # === Block form, with shorthand # # # You can also use the column types as method calls, rather than calling the column method. # create_table(:suppliers) do |t| # t.string :name, limit: 60 # # Other fields here # end # # === Regular form # # # Creates a table called 'suppliers' with no columns. # create_table(:suppliers) # # Add a column to 'suppliers'. # add_column(:suppliers, :name, :string, {limit: 60}) # # The +options+ hash can include the following keys: # [:id] # Whether to automatically add a primary key column. Defaults to true. # Join tables for {ActiveRecord::Base.has_and_belongs_to_many}[rdoc-ref:Associations::ClassMethods#has_and_belongs_to_many] should set it to false. # # A Symbol can be used to specify the type of the generated primary key column. # [:primary_key] # The name of the primary key, if one is to be added automatically. # Defaults to +id+. If :id is false this option is ignored. # # Note that Active Record models will automatically detect their # primary key. This can be avoided by using # {self.primary_key=}[rdoc-ref:AttributeMethods::PrimaryKey::ClassMethods#primary_key=] on the model # to define the key explicitly. # # [:options] # Any extra options you want appended to the table definition. # [:temporary] # Make a temporary table. # [:force] # Set to true to drop the table before creating it. # Set to +:cascade+ to drop dependent objects as well. # Defaults to false. # [:as] # SQL to use to generate the table. When this option is used, the block is # ignored, as are the :id and :primary_key options. # # ====== Add a backend specific option to the generated SQL (MySQL) # # create_table(:suppliers, options: 'ENGINE=InnoDB DEFAULT CHARSET=utf8') # # generates: # # CREATE TABLE suppliers ( # id int auto_increment PRIMARY KEY # ) ENGINE=InnoDB DEFAULT CHARSET=utf8 # # ====== Rename the primary key column # # create_table(:objects, primary_key: 'guid') do |t| # t.column :name, :string, limit: 80 # end # # generates: # # CREATE TABLE objects ( # guid int auto_increment PRIMARY KEY, # name varchar(80) # ) # # ====== Change the primary key column type # # create_table(:tags, id: :string) do |t| # t.column :label, :string # end # # generates: # # CREATE TABLE tags ( # id varchar PRIMARY KEY, # label varchar # ) # # ====== Do not add a primary key column # # create_table(:categories_suppliers, id: false) do |t| # t.column :category_id, :integer # t.column :supplier_id, :integer # end # # generates: # # CREATE TABLE categories_suppliers ( # category_id int, # supplier_id int # ) # # ====== Create a temporary table based on a query # # create_table(:long_query, temporary: true, # as: "SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id") # # generates: # # CREATE TEMPORARY TABLE long_query AS # SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id # # See also TableDefinition#column for details on how to create columns. def create_table(table_name, comment: nil, **options) td = create_table_definition table_name, options[:temporary], options[:options], options[:as], comment: comment if options[:id] != false && !options[:as] pk = options.fetch(:primary_key) do Base.get_primary_key table_name.to_s.singularize end if pk.is_a?(Array) td.primary_keys pk else td.primary_key pk, options.fetch(:id, :primary_key), options end end yield td if block_given? if options[:force] && data_source_exists?(table_name) drop_table(table_name, options) end result = execute schema_creation.accept td unless supports_indexes_in_create? td.indexes.each do |column_name, index_options| add_index(table_name, column_name, index_options) end end if supports_comments? && !supports_comments_in_create? change_table_comment(table_name, comment) if comment.present? td.columns.each do |column| change_column_comment(table_name, column.name, column.comment) if column.comment.present? end end result end # Creates a new join table with the name created using the lexical order of the first two # arguments. These arguments can be a String or a Symbol. # # # Creates a table called 'assemblies_parts' with no id. # create_join_table(:assemblies, :parts) # # You can pass a +options+ hash can include the following keys: # [:table_name] # Sets the table name overriding the default # [:column_options] # Any extra options you want appended to the columns definition. # [:options] # Any extra options you want appended to the table definition. # [:temporary] # Make a temporary table. # [:force] # Set to true to drop the table before creating it. # Defaults to false. # # Note that #create_join_table does not create any indices by default; you can use # its block form to do so yourself: # # create_join_table :products, :categories do |t| # t.index :product_id # t.index :category_id # end # # ====== Add a backend specific option to the generated SQL (MySQL) # # create_join_table(:assemblies, :parts, options: 'ENGINE=InnoDB DEFAULT CHARSET=utf8') # # generates: # # CREATE TABLE assemblies_parts ( # assembly_id int NOT NULL, # part_id int NOT NULL, # ) ENGINE=InnoDB DEFAULT CHARSET=utf8 # def create_join_table(table_1, table_2, options = {}) join_table_name = find_join_table_name(table_1, table_2, options) column_options = options.delete(:column_options) || {} column_options.reverse_merge!(null: false) type = column_options.delete(:type) || :integer t1_column, t2_column = [table_1, table_2].map{ |t| t.to_s.singularize.foreign_key } create_table(join_table_name, options.merge!(id: false)) do |td| td.send type, t1_column, column_options td.send type, t2_column, column_options yield td if block_given? end end # Drops the join table specified by the given arguments. # See #create_join_table for details. # # Although this command ignores the block if one is given, it can be helpful # to provide one in a migration's +change+ method so it can be reverted. # In that case, the block will be used by #create_join_table. def drop_join_table(table_1, table_2, options = {}) join_table_name = find_join_table_name(table_1, table_2, options) drop_table(join_table_name) end # A block for changing columns in +table+. # # # change_table() yields a Table instance # change_table(:suppliers) do |t| # t.column :name, :string, limit: 60 # # Other column alterations here # end # # The +options+ hash can include the following keys: # [:bulk] # Set this to true to make this a bulk alter query, such as # # ALTER TABLE `users` ADD COLUMN age INT, ADD COLUMN birthdate DATETIME ... # # Defaults to false. # # ====== Add a column # # change_table(:suppliers) do |t| # t.column :name, :string, limit: 60 # end # # ====== Add 2 integer columns # # change_table(:suppliers) do |t| # t.integer :width, :height, null: false, default: 0 # end # # ====== Add created_at/updated_at columns # # change_table(:suppliers) do |t| # t.timestamps # end # # ====== Add a foreign key column # # change_table(:suppliers) do |t| # t.references :company # end # # Creates a company_id(integer) column. # # ====== Add a polymorphic foreign key column # # change_table(:suppliers) do |t| # t.belongs_to :company, polymorphic: true # end # # Creates company_type(varchar) and company_id(integer) columns. # # ====== Remove a column # # change_table(:suppliers) do |t| # t.remove :company # end # # ====== Remove several columns # # change_table(:suppliers) do |t| # t.remove :company_id # t.remove :width, :height # end # # ====== Remove an index # # change_table(:suppliers) do |t| # t.remove_index :company_id # end # # See also Table for details on all of the various column transformation. def change_table(table_name, options = {}) if supports_bulk_alter? && options[:bulk] recorder = ActiveRecord::Migration::CommandRecorder.new(self) yield update_table_definition(table_name, recorder) bulk_change_table(table_name, recorder.commands) else yield update_table_definition(table_name, self) end end # Renames a table. # # rename_table('octopuses', 'octopi') # def rename_table(table_name, new_name) raise NotImplementedError, "rename_table is not implemented" end # Drops a table from the database. # # [:force] # Set to +:cascade+ to drop dependent objects as well. # Defaults to false. # [:if_exists] # Set to +true+ to only drop the table if it exists. # Defaults to false. # # Although this command ignores most +options+ and the block if one is given, # it can be helpful to provide these in a migration's +change+ method so it can be reverted. # In that case, +options+ and the block will be used by #create_table. def drop_table(table_name, options = {}) execute "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}" end # Add a new +type+ column named +column_name+ to +table_name+. # # The +type+ parameter is normally one of the migrations native types, # which is one of the following: # :primary_key, :string, :text, # :integer, :bigint, :float, :decimal, :numeric, # :datetime, :time, :date, # :binary, :boolean. # # You may use a type not in this list as long as it is supported by your # database (for example, "polygon" in MySQL), but this will not be database # agnostic and should usually be avoided. # # Available options are (none of these exists by default): # * :limit - # Requests a maximum column length. This is number of characters for a :string column # and number of bytes for :text, :binary and :integer columns. # * :default - # The column's default value. Use nil for NULL. # * :null - # Allows or disallows +NULL+ values in the column. This option could # have been named :null_allowed. # * :precision - # Specifies the precision for the :decimal and :numeric columns. # * :scale - # Specifies the scale for the :decimal and :numeric columns. # # Note: The precision is the total number of significant digits # and the scale is the number of digits that can be stored following # the decimal point. For example, the number 123.45 has a precision of 5 # and a scale of 2. A decimal with a precision of 5 and a scale of 2 can # range from -999.99 to 999.99. # # Please be aware of different RDBMS implementations behavior with # :decimal columns: # * The SQL standard says the default scale should be 0, :scale <= # :precision, and makes no comments about the requirements of # :precision. # * MySQL: :precision [1..63], :scale [0..30]. # Default is (10,0). # * PostgreSQL: :precision [1..infinity], # :scale [0..infinity]. No default. # * SQLite3: No restrictions on :precision and :scale, # but the maximum supported :precision is 16. No default. # * Oracle: :precision [1..38], :scale [-84..127]. # Default is (38,0). # * DB2: :precision [1..63], :scale [0..62]. # Default unknown. # * SqlServer?: :precision [1..38], :scale [0..38]. # Default (38,0). # # == Examples # # add_column(:users, :picture, :binary, limit: 2.megabytes) # # ALTER TABLE "users" ADD "picture" blob(2097152) # # add_column(:articles, :status, :string, limit: 20, default: 'draft', null: false) # # ALTER TABLE "articles" ADD "status" varchar(20) DEFAULT 'draft' NOT NULL # # add_column(:answers, :bill_gates_money, :decimal, precision: 15, scale: 2) # # ALTER TABLE "answers" ADD "bill_gates_money" decimal(15,2) # # add_column(:measurements, :sensor_reading, :decimal, precision: 30, scale: 20) # # ALTER TABLE "measurements" ADD "sensor_reading" decimal(30,20) # # # While :scale defaults to zero on most databases, it # # probably wouldn't hurt to include it. # add_column(:measurements, :huge_integer, :decimal, precision: 30) # # ALTER TABLE "measurements" ADD "huge_integer" decimal(30) # # # Defines a column with a database-specific type. # add_column(:shapes, :triangle, 'polygon') # # ALTER TABLE "shapes" ADD "triangle" polygon def add_column(table_name, column_name, type, options = {}) at = create_alter_table table_name at.add_column(column_name, type, options) execute schema_creation.accept at end # Removes the given columns from the table definition. # # remove_columns(:suppliers, :qualification, :experience) # def remove_columns(table_name, *column_names) raise ArgumentError.new("You must specify at least one column name. Example: remove_columns(:people, :first_name)") if column_names.empty? column_names.each do |column_name| remove_column(table_name, column_name) end end # Removes the column from the table definition. # # remove_column(:suppliers, :qualification) # # The +type+ and +options+ parameters will be ignored if present. It can be helpful # to provide these in a migration's +change+ method so it can be reverted. # In that case, +type+ and +options+ will be used by add_column. def remove_column(table_name, column_name, type = nil, options = {}) execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{quote_column_name(column_name)}" end # Changes the column's definition according to the new options. # See TableDefinition#column for details of the options you can use. # # change_column(:suppliers, :name, :string, limit: 80) # change_column(:accounts, :description, :text) # def change_column(table_name, column_name, type, options = {}) raise NotImplementedError, "change_column is not implemented" end # Sets a new default value for a column: # # change_column_default(:suppliers, :qualification, 'new') # change_column_default(:accounts, :authorized, 1) # # Setting the default to +nil+ effectively drops the default: # # change_column_default(:users, :email, nil) # # Passing a hash containing +:from+ and +:to+ will make this change # reversible in migration: # # change_column_default(:posts, :state, from: nil, to: "draft") # def change_column_default(table_name, column_name, default_or_changes) raise NotImplementedError, "change_column_default is not implemented" end # Sets or removes a NOT NULL constraint on a column. The +null+ flag # indicates whether the value can be +NULL+. For example # # change_column_null(:users, :nickname, false) # # says nicknames cannot be +NULL+ (adds the constraint), whereas # # change_column_null(:users, :nickname, true) # # allows them to be +NULL+ (drops the constraint). # # The method accepts an optional fourth argument to replace existing # NULLs with some other value. Use that one when enabling the # constraint if needed, since otherwise those rows would not be valid. # # Please note the fourth argument does not set a column's default. def change_column_null(table_name, column_name, null, default = nil) raise NotImplementedError, "change_column_null is not implemented" end # Renames a column. # # rename_column(:suppliers, :description, :name) # def rename_column(table_name, column_name, new_column_name) raise NotImplementedError, "rename_column is not implemented" end # Adds a new index to the table. +column_name+ can be a single Symbol, or # an Array of Symbols. # # The index will be named after the table and the column name(s), unless # you pass :name as an option. # # ====== Creating a simple index # # add_index(:suppliers, :name) # # generates: # # CREATE INDEX suppliers_name_index ON suppliers(name) # # ====== Creating a unique index # # add_index(:accounts, [:branch_id, :party_id], unique: true) # # generates: # # CREATE UNIQUE INDEX accounts_branch_id_party_id_index ON accounts(branch_id, party_id) # # ====== Creating a named index # # add_index(:accounts, [:branch_id, :party_id], unique: true, name: 'by_branch_party') # # generates: # # CREATE UNIQUE INDEX by_branch_party ON accounts(branch_id, party_id) # # ====== Creating an index with specific key length # # add_index(:accounts, :name, name: 'by_name', length: 10) # # generates: # # CREATE INDEX by_name ON accounts(name(10)) # # ====== Creating an index with specific key lengths for multiple keys # # add_index(:accounts, [:name, :surname], name: 'by_name_surname', length: {name: 10, surname: 15}) # # generates: # # CREATE INDEX by_name_surname ON accounts(name(10), surname(15)) # # Note: SQLite doesn't support index length. # # ====== Creating an index with a sort order (desc or asc, asc is the default) # # add_index(:accounts, [:branch_id, :party_id, :surname], order: {branch_id: :desc, party_id: :asc}) # # generates: # # CREATE INDEX by_branch_desc_party ON accounts(branch_id DESC, party_id ASC, surname) # # Note: MySQL doesn't yet support index order (it accepts the syntax but ignores it). # # ====== Creating a partial index # # add_index(:accounts, [:branch_id, :party_id], unique: true, where: "active") # # generates: # # CREATE UNIQUE INDEX index_accounts_on_branch_id_and_party_id ON accounts(branch_id, party_id) WHERE active # # Note: Partial indexes are only supported for PostgreSQL and SQLite 3.8.0+. # # ====== Creating an index with a specific method # # add_index(:developers, :name, using: 'btree') # # generates: # # CREATE INDEX index_developers_on_name ON developers USING btree (name) -- PostgreSQL # CREATE INDEX index_developers_on_name USING btree ON developers (name) -- MySQL # # Note: only supported by PostgreSQL and MySQL # # ====== Creating an index with a specific type # # add_index(:developers, :name, type: :fulltext) # # generates: # # CREATE FULLTEXT INDEX index_developers_on_name ON developers (name) -- MySQL # # Note: only supported by MySQL. def add_index(table_name, column_name, options = {}) index_name, index_type, index_columns, index_options = add_index_options(table_name, column_name, options) execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{index_columns})#{index_options}" end # Removes the given index from the table. # # Removes the index on +branch_id+ in the +accounts+ table if exactly one such index exists. # # remove_index :accounts, :branch_id # # Removes the index on +branch_id+ in the +accounts+ table if exactly one such index exists. # # remove_index :accounts, column: :branch_id # # Removes the index on +branch_id+ and +party_id+ in the +accounts+ table if exactly one such index exists. # # remove_index :accounts, column: [:branch_id, :party_id] # # Removes the index named +by_branch_party+ in the +accounts+ table. # # remove_index :accounts, name: :by_branch_party # def remove_index(table_name, options = {}) index_name = index_name_for_remove(table_name, options) execute "DROP INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)}" end # Renames an index. # # Rename the +index_people_on_last_name+ index to +index_users_on_last_name+: # # rename_index :people, 'index_people_on_last_name', 'index_users_on_last_name' # def rename_index(table_name, old_name, new_name) validate_index_length!(table_name, new_name) # this is a naive implementation; some DBs may support this more efficiently (Postgres, for instance) old_index_def = indexes(table_name).detect { |i| i.name == old_name } return unless old_index_def add_index(table_name, old_index_def.columns, name: new_name, unique: old_index_def.unique) remove_index(table_name, name: old_name) end def index_name(table_name, options) #:nodoc: if Hash === options if options[:column] "index_#{table_name}_on_#{Array(options[:column]) * '_and_'}" elsif options[:name] options[:name] else raise ArgumentError, "You must specify the index name" end else index_name(table_name, index_name_options(options)) end end # Verifies the existence of an index with a given name. # # The default argument is returned if the underlying implementation does not define the indexes method, # as there's no way to determine the correct answer in that case. def index_name_exists?(table_name, index_name, default) return default unless respond_to?(:indexes) index_name = index_name.to_s indexes(table_name).detect { |i| i.name == index_name } end # Adds a reference. The reference column is an integer by default, # the :type option can be used to specify a different type. # Optionally adds a +_type+ column, if :polymorphic option is provided. # #add_reference and #add_belongs_to are acceptable. # # The +options+ hash can include the following keys: # [:type] # The reference column type. Defaults to +:integer+. # [:index] # Add an appropriate index. Defaults to true. # See #add_index for usage of this option. # [:foreign_key] # Add an appropriate foreign key constraint. Defaults to false. # [:polymorphic] # Whether an additional +_type+ column should be added. Defaults to false. # [:null] # Whether the column allows nulls. Defaults to true. # # ====== Create a user_id integer column # # add_reference(:products, :user) # # ====== Create a user_id string column # # add_reference(:products, :user, type: :string) # # ====== Create supplier_id, supplier_type columns and appropriate index # # add_reference(:products, :supplier, polymorphic: true, index: true) # # ====== Create a supplier_id column with a unique index # # add_reference(:products, :supplier, index: { unique: true }) # # ====== Create a supplier_id column with a named index # # add_reference(:products, :supplier, index: { name: "my_supplier_index" }) # # ====== Create a supplier_id column and appropriate foreign key # # add_reference(:products, :supplier, foreign_key: true) # # ====== Create a supplier_id column and a foreign key to the firms table # # add_reference(:products, :supplier, foreign_key: {to_table: :firms}) # def add_reference(table_name, *args) ReferenceDefinition.new(*args).add_to(update_table_definition(table_name, self)) end alias :add_belongs_to :add_reference # Removes the reference(s). Also removes a +type+ column if one exists. # #remove_reference and #remove_belongs_to are acceptable. # # ====== Remove the reference # # remove_reference(:products, :user, index: true) # # ====== Remove polymorphic reference # # remove_reference(:products, :supplier, polymorphic: true) # # ====== Remove the reference with a foreign key # # remove_reference(:products, :user, index: true, foreign_key: true) # def remove_reference(table_name, ref_name, foreign_key: false, polymorphic: false, **options) if foreign_key reference_name = Base.pluralize_table_names ? ref_name.to_s.pluralize : ref_name if foreign_key.is_a?(Hash) foreign_key_options = foreign_key else foreign_key_options = { to_table: reference_name } end remove_foreign_key(table_name, **foreign_key_options) end remove_column(table_name, "#{ref_name}_id") remove_column(table_name, "#{ref_name}_type") if polymorphic end alias :remove_belongs_to :remove_reference # Returns an array of foreign keys for the given table. # The foreign keys are represented as ForeignKeyDefinition objects. def foreign_keys(table_name) raise NotImplementedError, "foreign_keys is not implemented" end # Adds a new foreign key. +from_table+ is the table with the key column, # +to_table+ contains the referenced primary key. # # The foreign key will be named after the following pattern: fk_rails_. # +identifier+ is a 10 character long string which is deterministically generated from the # +from_table+ and +column+. A custom name can be specified with the :name option. # # ====== Creating a simple foreign key # # add_foreign_key :articles, :authors # # generates: # # ALTER TABLE "articles" ADD CONSTRAINT fk_rails_e74ce85cbc FOREIGN KEY ("author_id") REFERENCES "authors" ("id") # # ====== Creating a foreign key on a specific column # # add_foreign_key :articles, :users, column: :author_id, primary_key: "lng_id" # # generates: # # ALTER TABLE "articles" ADD CONSTRAINT fk_rails_58ca3d3a82 FOREIGN KEY ("author_id") REFERENCES "users" ("lng_id") # # ====== Creating a cascading foreign key # # add_foreign_key :articles, :authors, on_delete: :cascade # # generates: # # ALTER TABLE "articles" ADD CONSTRAINT fk_rails_e74ce85cbc FOREIGN KEY ("author_id") REFERENCES "authors" ("id") ON DELETE CASCADE # # The +options+ hash can include the following keys: # [:column] # The foreign key column name on +from_table+. Defaults to to_table.singularize + "_id" # [:primary_key] # The primary key column name on +to_table+. Defaults to +id+. # [:name] # The constraint name. Defaults to fk_rails_. # [:on_delete] # Action that happens ON DELETE. Valid values are +:nullify+, +:cascade+ and +:restrict+ # [:on_update] # Action that happens ON UPDATE. Valid values are +:nullify+, +:cascade+ and +:restrict+ def add_foreign_key(from_table, to_table, options = {}) return unless supports_foreign_keys? options = foreign_key_options(from_table, to_table, options) at = create_alter_table from_table at.add_foreign_key to_table, options execute schema_creation.accept(at) end # Removes the given foreign key from the table. Any option parameters provided # will be used to re-add the foreign key in case of a migration rollback. # It is recommended that you provide any options used when creating the foreign # key so that the migration can be reverted properly. # # Removes the foreign key on +accounts.branch_id+. # # remove_foreign_key :accounts, :branches # # Removes the foreign key on +accounts.owner_id+. # # remove_foreign_key :accounts, column: :owner_id # # Removes the foreign key named +special_fk_name+ on the +accounts+ table. # # remove_foreign_key :accounts, name: :special_fk_name # # The +options+ hash accepts the same keys as SchemaStatements#add_foreign_key. def remove_foreign_key(from_table, options_or_to_table = {}) return unless supports_foreign_keys? fk_name_to_delete = foreign_key_for!(from_table, options_or_to_table).name at = create_alter_table from_table at.drop_foreign_key fk_name_to_delete execute schema_creation.accept(at) end # Checks to see if a foreign key exists on a table for a given foreign key definition. # # # Check a foreign key exists # foreign_key_exists?(:accounts, :branches) # # # Check a foreign key on a specified column exists # foreign_key_exists?(:accounts, column: :owner_id) # # # Check a foreign key with a custom name exists # foreign_key_exists?(:accounts, name: "special_fk_name") # def foreign_key_exists?(from_table, options_or_to_table = {}) foreign_key_for(from_table, options_or_to_table).present? end def foreign_key_for(from_table, options_or_to_table = {}) # :nodoc: return unless supports_foreign_keys? foreign_keys(from_table).detect {|fk| fk.defined_for? options_or_to_table } end def foreign_key_for!(from_table, options_or_to_table = {}) # :nodoc: foreign_key_for(from_table, options_or_to_table) or \ raise ArgumentError, "Table '#{from_table}' has no foreign key for #{options_or_to_table}" end def foreign_key_column_for(table_name) # :nodoc: prefix = Base.table_name_prefix suffix = Base.table_name_suffix name = table_name.to_s =~ /#{prefix}(.+)#{suffix}/ ? $1 : table_name.to_s "#{name.singularize}_id" end def foreign_key_options(from_table, to_table, options) # :nodoc: options = options.dup options[:column] ||= foreign_key_column_for(to_table) options[:name] ||= foreign_key_name(from_table, options) options end def dump_schema_information #:nodoc: versions = ActiveRecord::SchemaMigration.order('version').pluck(:version) insert_versions_sql(versions) if versions.any? end def insert_versions_sql(versions) # :nodoc: sm_table = quote_table_name(ActiveRecord::Migrator.schema_migrations_table_name) if versions.is_a?(Array) sql = "INSERT INTO #{sm_table} (version) VALUES\n" sql << versions.map { |v| "(#{quote(v)})" }.join(",\n") sql << ";\n\n" sql else "INSERT INTO #{sm_table} (version) VALUES (#{quote(versions)});" end end # Should not be called normally, but this operation is non-destructive. # The migrations module handles this automatically. def initialize_schema_migrations_table ActiveRecord::SchemaMigration.create_table end def initialize_internal_metadata_table ActiveRecord::InternalMetadata.create_table end def internal_string_options_for_primary_key # :nodoc: { primary_key: true } end def assume_migrated_upto_version(version, migrations_paths) migrations_paths = Array(migrations_paths) version = version.to_i sm_table = quote_table_name(ActiveRecord::Migrator.schema_migrations_table_name) migrated = select_values("SELECT version FROM #{sm_table}").map(&:to_i) versions = ActiveRecord::Migrator.migration_files(migrations_paths).map do |file| ActiveRecord::Migrator.parse_migration_filename(file).first.to_i end unless migrated.include?(version) execute "INSERT INTO #{sm_table} (version) VALUES (#{quote(version)})" end inserting = (versions - migrated).select {|v| v < version} if inserting.any? if (duplicate = inserting.detect {|v| inserting.count(v) > 1}) raise "Duplicate migration #{duplicate}. Please renumber your migrations to resolve the conflict." end if supports_multi_insert? execute insert_versions_sql(inserting) else inserting.each do |v| execute insert_versions_sql(v) end end end end def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc: type = type.to_sym if type if native = native_database_types[type] column_type_sql = (native.is_a?(Hash) ? native[:name] : native).dup if type == :decimal # ignore limit, use precision and scale scale ||= native[:scale] if precision ||= native[:precision] if scale column_type_sql << "(#{precision},#{scale})" else column_type_sql << "(#{precision})" end elsif scale raise ArgumentError, "Error adding decimal column: precision cannot be empty if scale is specified" end elsif [:datetime, :time].include?(type) && precision ||= native[:precision] if (0..6) === precision column_type_sql << "(#{precision})" else raise(ActiveRecordError, "No #{native[:name]} type has precision of #{precision}. The allowed range of precision is from 0 to 6") end elsif (type != :primary_key) && (limit ||= native.is_a?(Hash) && native[:limit]) column_type_sql << "(#{limit})" end column_type_sql else type.to_s end end # Given a set of columns and an ORDER BY clause, returns the columns for a SELECT DISTINCT. # PostgreSQL, MySQL, and Oracle overrides this for custom DISTINCT syntax - they # require the order columns appear in the SELECT. # # columns_for_distinct("posts.id", ["posts.created_at desc"]) # def columns_for_distinct(columns, orders) # :nodoc: columns end # Adds timestamps (+created_at+ and +updated_at+) columns to +table_name+. # Additional options (like +:null+) are forwarded to #add_column. # # add_timestamps(:suppliers, null: true) # def add_timestamps(table_name, options = {}) options[:null] = false if options[:null].nil? add_column table_name, :created_at, :datetime, options add_column table_name, :updated_at, :datetime, options end # Removes the timestamp columns (+created_at+ and +updated_at+) from the table definition. # # remove_timestamps(:suppliers) # def remove_timestamps(table_name, options = {}) remove_column table_name, :updated_at remove_column table_name, :created_at end def update_table_definition(table_name, base) #:nodoc: Table.new(table_name, base) end def add_index_options(table_name, column_name, comment: nil, **options) # :nodoc: column_names = index_column_names(column_name) options.assert_valid_keys(:unique, :order, :name, :where, :length, :internal, :using, :algorithm, :type) index_type = options[:type].to_s if options.key?(:type) index_type ||= options[:unique] ? "UNIQUE" : "" index_name = options[:name].to_s if options.key?(:name) index_name ||= index_name(table_name, column_names) max_index_length = options.fetch(:internal, false) ? index_name_length : allowed_index_name_length if options.key?(:algorithm) algorithm = index_algorithms.fetch(options[:algorithm]) { raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}") } end using = "USING #{options[:using]}" if options[:using].present? if supports_partial_index? index_options = options[:where] ? " WHERE #{options[:where]}" : "" end if index_name.length > max_index_length raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{max_index_length} characters" end if data_source_exists?(table_name) && index_name_exists?(table_name, index_name, false) raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' already exists" end index_columns = quoted_columns_for_index(column_names, options).join(", ") [index_name, index_type, index_columns, index_options, algorithm, using, comment] end def options_include_default?(options) options.include?(:default) && !(options[:null] == false && options[:default].nil?) end # Changes the comment for a table or removes it if +nil+. def change_table_comment(table_name, comment) raise NotImplementedError, "#{self.class} does not support changing table comments" end # Changes the comment for a column or removes it if +nil+. def change_column_comment(table_name, column_name, comment) #:nodoc: raise NotImplementedError, "#{self.class} does not support changing column comments" end protected def add_index_sort_order(quoted_columns, **options) if order = options[:order] case order when Hash order = order.symbolize_keys quoted_columns.each { |name, column| column << " #{order[name].upcase}" if order[name].present? } when String quoted_columns.each { |name, column| column << " #{order.upcase}" if order.present? } end end quoted_columns end # Overridden by the MySQL adapter for supporting index lengths def add_options_for_index_columns(quoted_columns, **options) if supports_index_sort_order? quoted_columns = add_index_sort_order(quoted_columns, options) end quoted_columns end def quoted_columns_for_index(column_names, **options) return [column_names] if column_names.is_a?(String) quoted_columns = Hash[column_names.map { |name| [name.to_sym, quote_column_name(name).dup] }] add_options_for_index_columns(quoted_columns, options).values end def index_name_for_remove(table_name, options = {}) return options[:name] if can_remove_index_by_name?(options) # if the adapter doesn't support the indexes call the best we can do # is return the default index name for the options provided return index_name(table_name, options) unless respond_to?(:indexes) checks = [] if options.is_a?(Hash) checks << lambda { |i| i.name == options[:name].to_s } if options.key?(:name) column_names = index_column_names(options[:column]) else column_names = index_column_names(options) end if column_names.present? checks << lambda { |i| index_name(table_name, i.columns) == index_name(table_name, column_names) } end raise ArgumentError, "No name or columns specified" if checks.none? matching_indexes = indexes(table_name).select { |i| checks.all? { |check| check[i] } } if matching_indexes.count > 1 raise ArgumentError, "Multiple indexes found on #{table_name} columns #{column_names}. " \ "Specify an index name from #{matching_indexes.map(&:name).join(', ')}" elsif matching_indexes.none? raise ArgumentError, "No indexes found on #{table_name} with the options provided." else matching_indexes.first.name end end def rename_table_indexes(table_name, new_name) indexes(new_name).each do |index| generated_index_name = index_name(table_name, column: index.columns) if generated_index_name == index.name rename_index new_name, generated_index_name, index_name(new_name, column: index.columns) end end end def rename_column_indexes(table_name, column_name, new_column_name) column_name, new_column_name = column_name.to_s, new_column_name.to_s indexes(table_name).each do |index| next unless index.columns.include?(new_column_name) old_columns = index.columns.dup old_columns[old_columns.index(new_column_name)] = column_name generated_index_name = index_name(table_name, column: old_columns) if generated_index_name == index.name rename_index table_name, generated_index_name, index_name(table_name, column: index.columns) end end end private def create_table_definition(*args) TableDefinition.new(*args) end def create_alter_table(name) AlterTable.new create_table_definition(name) end def index_column_names(column_names) if column_names.is_a?(String) && /\W/ === column_names column_names else Array(column_names) end end def index_name_options(column_names) # :nodoc: if column_names.is_a?(String) && /\W/ === column_names column_names = column_names.scan(/\w+/).join('_') end { column: column_names } end def foreign_key_name(table_name, options) # :nodoc: identifier = "#{table_name}_#{options.fetch(:column)}_fk" hashed_identifier = Digest::SHA256.hexdigest(identifier).first(10) options.fetch(:name) do "fk_rails_#{hashed_identifier}" end end def validate_index_length!(table_name, new_name) # :nodoc: if new_name.length > allowed_index_name_length raise ArgumentError, "Index name '#{new_name}' on table '#{table_name}' is too long; the limit is #{allowed_index_name_length} characters" end end def extract_new_default_value(default_or_changes) if default_or_changes.is_a?(Hash) && default_or_changes.has_key?(:from) && default_or_changes.has_key?(:to) default_or_changes[:to] else default_or_changes end end def can_remove_index_by_name?(options) options.is_a?(Hash) && options.key?(:name) && options.except(:name, :algorithm).empty? end end end end