require 'active_support/core_ext/array/wrap' require 'active_support/deprecation/reporting' module ActiveRecord module ConnectionAdapters # :nodoc: module SchemaStatements # 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 # Truncates a table alias according to the limits of the current adapter. def table_alias_for(table_name) table_name[0...table_alias_length].gsub(/\./, '_') end # def tables(name = nil) end # Checks to see if the table +table_name+ exists on the database. # # === Example # table_exists?(:developers) def table_exists?(table_name) tables.include?(table_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. # # === Examples # # 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.wrap(column_name) index_name = options.key?(:name) ? options[:name].to_s : index_name(table_name, :column => column_names) if options[:unique] indexes(table_name).any?{ |i| i.unique && i.name == index_name } else indexes(table_name).any?{ |i| i.name == index_name } end 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, name = nil) end # Checks to see if a column exists in a given table. # # === Examples # # 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) def column_exists?(table_name, column_name, type = nil, options = {}) columns(table_name).any?{ |c| c.name == column_name.to_s && (!type || c.type == type) && (!options[:limit] || c.limit == options[:limit]) && (!options[:precision] || c.precision == options[:precision]) && (!options[:scale] || c.scale == options[:scale]) } 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 +has_and_belongs_to_many+ should set it to false. # [: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. # # Also note that this just sets the primary key in the table. You additionally # need to configure the primary key in the model via the +set_primary_key+ macro. # Models do NOT auto-detect the primary key from their table 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. # # ===== Examples # ====== 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(11) DEFAULT NULL 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(11) DEFAULT NULL auto_increment PRIMARY KEY, # name varchar(80) # ) # # ====== 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 # ) # # See also TableDefinition#column for details on how to create columns. def create_table(table_name, options = {}) td = table_definition td.primary_key(options[:primary_key] || Base.get_primary_key(table_name.to_s.singularize)) unless options[:id] == false yield td if block_given? if options[:force] && table_exists?(table_name) drop_table(table_name) end create_sql = "CREATE#{' TEMPORARY' if options[:temporary]} TABLE " create_sql << "#{quote_table_name(table_name)} (" create_sql << td.to_sql create_sql << ") #{options[:options]}" execute create_sql end # A block for changing columns in +table+. # # === Example # # 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(11), ADD COLUMN birthdate DATETIME ... # # Defaults to false. # # ===== Examples # ====== 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 Table.new(table_name, recorder) bulk_change_table(table_name, recorder.commands) else yield Table.new(table_name, self) end end # Renames a table. # ===== Example # 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. def drop_table(table_name) execute "DROP TABLE #{quote_table_name(table_name)}" end # Adds a new column to the named table. # See TableDefinition#column for details of the options you can use. def add_column(table_name, column_name, type, options = {}) add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}" add_column_options!(add_column_sql, options) execute(add_column_sql) end # Removes the column(s) from the table definition. # ===== Examples # remove_column(:suppliers, :qualification) # remove_columns(:suppliers, :qualification, :experience) def remove_column(table_name, *column_names) columns_for_remove(table_name, *column_names).each {|column_name| execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{column_name}" } end alias :remove_columns :remove_column # Changes the column's definition according to the new options. # See TableDefinition#column for details of the options you can use. # ===== Examples # 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. # ===== Examples # change_column_default(:suppliers, :qualification, 'new') # change_column_default(:accounts, :authorized, 1) # change_column_default(:users, :email, nil) def change_column_default(table_name, column_name, default) raise NotImplementedError, "change_column_default is not implemented" end # Renames a column. # ===== Example # 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 first column name, # unless you pass :name as an option. # # When creating an index on multiple columns, the first column is used as a name # for the index. For example, when you specify an index on two columns # [:first, :last], the DBMS creates an index for both columns as well as an # index for the first column :first. Using just the first name for this index # makes sense, because you will never have to create a singular index with this # name. # # ===== Examples # # ====== 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)) # # 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, :part_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) # def add_index(table_name, column_name, options = {}) index_name, index_type, index_columns = 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})" end # Remove the given index from the table. # # Remove the index_accounts_on_column in the accounts table. # remove_index :accounts, :column # Remove the index named index_accounts_on_branch_id in the accounts table. # remove_index :accounts, :column => :branch_id # Remove the index named index_accounts_on_branch_id_and_party_id in the accounts table. # remove_index :accounts, :column => [:branch_id, :party_id] # Remove the index named by_branch_party in the accounts table. # remove_index :accounts, :name => :by_branch_party def remove_index(table_name, options = {}) remove_index!(table_name, index_name_for_remove(table_name, options)) end def remove_index!(table_name, index_name) #:nodoc: execute "DROP INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)}" end # Rename 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) # 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 remove_index(table_name, :name => old_name) add_index(table_name, old_index_def.columns, :name => new_name, :unique => old_index_def.unique) end def index_name(table_name, options) #:nodoc: if Hash === options # legacy support if options[:column] "index_#{table_name}_on_#{Array.wrap(options[:column]) * '_and_'}" elsif options[:name] options[:name] else raise ArgumentError, "You must specify the index name" end else index_name(table_name, :column => options) end end # Verify 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 # Returns a string of CREATE TABLE SQL statement(s) for recreating the # entire structure of the database. def structure_dump end def dump_schema_information #:nodoc: sm_table = ActiveRecord::Migrator.schema_migrations_table_name migrated = select_values("SELECT version FROM #{sm_table} ORDER BY version") migrated.map { |v| "INSERT INTO #{sm_table} (version) VALUES ('#{v}');" }.join("\n\n") end # Should not be called normally, but this operation is non-destructive. # The migrations module handles this automatically. def initialize_schema_migrations_table sm_table = ActiveRecord::Migrator.schema_migrations_table_name unless table_exists?(sm_table) create_table(sm_table, :id => false) do |schema_migrations_table| schema_migrations_table.column :version, :string, :null => false end add_index sm_table, :version, :unique => true, :name => "#{Base.table_name_prefix}unique_schema_migrations#{Base.table_name_suffix}" # Backwards-compatibility: if we find schema_info, assume we've # migrated up to that point: si_table = Base.table_name_prefix + 'schema_info' + Base.table_name_suffix if table_exists?(si_table) ActiveRecord::Deprecation.warn "Usage of the schema table `#{si_table}` is deprecated. Please switch to using `schema_migrations` table" old_version = select_value("SELECT version FROM #{quote_table_name(si_table)}").to_i assume_migrated_upto_version(old_version) drop_table(si_table) end end end def assume_migrated_upto_version(version, migrations_paths = ActiveRecord::Migrator.migrations_paths) migrations_paths = Array.wrap(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 { |v| v.to_i } paths = migrations_paths.map {|p| "#{p}/[0-9]*_*.rb" } versions = Dir[*paths].map do |filename| filename.split('/').last.split('_').first.to_i end unless migrated.include?(version) execute "INSERT INTO #{sm_table} (version) VALUES ('#{version}')" end inserted = Set.new (versions - migrated).each do |v| if inserted.include?(v) raise "Duplicate migration #{v}. Please renumber your migrations to resolve the conflict." elsif v < version execute "INSERT INTO #{sm_table} (version) VALUES ('#{v}')" inserted << v end end end def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc: if native = native_database_types[type.to_sym] 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 if specified" end elsif (type != :primary_key) && (limit ||= native.is_a?(Hash) && native[:limit]) column_type_sql << "(#{limit})" end column_type_sql else type end end def add_column_options!(sql, options) #:nodoc: sql << " DEFAULT #{quote(options[:default], options[:column])}" if options_include_default?(options) # must explicitly check for :null to allow change_column to work on migrations if options[:null] == false sql << " NOT NULL" end end # SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause. # Both PostgreSQL and Oracle overrides this for custom DISTINCT syntax. # # distinct("posts.id", "posts.created_at desc") def distinct(columns, order_by) "DISTINCT #{columns}" end # Adds timestamps (created_at and updated_at) columns to the named table. # ===== Examples # add_timestamps(:suppliers) def add_timestamps(table_name) add_column table_name, :created_at, :datetime, :null => false add_column table_name, :updated_at, :datetime, :null => false end # Removes the timestamp columns (created_at and updated_at) from the table definition. # ===== Examples # remove_timestamps(:suppliers) def remove_timestamps(table_name) remove_column table_name, :updated_at remove_column table_name, :created_at end protected def add_index_sort_order(option_strings, column_names, options = {}) if options.is_a?(Hash) && order = options[:order] case order when Hash column_names.each {|name| option_strings[name] += " #{order[name].to_s.upcase}" if order.has_key?(name)} when String column_names.each {|name| option_strings[name] += " #{order.upcase}"} end end return option_strings end # Overridden by the mysql adapter for supporting index lengths def quoted_columns_for_index(column_names, options = {}) option_strings = Hash[column_names.map {|name| [name, '']}] # add index sort order if supported if supports_index_sort_order? option_strings = add_index_sort_order(option_strings, column_names, options) end column_names.map {|name| quote_column_name(name) + option_strings[name]} end def options_include_default?(options) options.include?(:default) && !(options[:null] == false && options[:default].nil?) end def add_index_options(table_name, column_name, options = {}) column_names = Array.wrap(column_name) index_name = index_name(table_name, :column => column_names) if Hash === options # legacy support, since this param was a string index_type = options[:unique] ? "UNIQUE" : "" index_name = options[:name].to_s if options.key?(:name) else index_type = options end if index_name.length > index_name_length raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{index_name_length} characters" end if 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] end def index_name_for_remove(table_name, options = {}) index_name = index_name(table_name, options) unless index_name_exists?(table_name, index_name, true) raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist" end index_name end def columns_for_remove(table_name, *column_names) column_names = column_names.flatten raise ArgumentError.new("You must specify at least one column name. Example: remove_column(:people, :first_name)") if column_names.blank? column_names.map {|column_name| quote_column_name(column_name) } end private def table_definition TableDefinition.new(self) end end end end