A Database object represents a virtual connection to a database. The Database class is meant to be subclassed by database adapters in order to provide the functionality needed for executing queries.
MYSQL_DATABASE_DISCONNECT_ERRORS | = | /\A(Commands out of sync; you can't run this command now|Can't connect to local MySQL server through socket|MySQL server has gone away)/ | Mysql::Error messages that indicate the current connection should be disconnected |
convert_types | [RW] | Whether to convert some Java types to ruby types when retrieving rows. True by default, can be set to false to roughly double performance when fetching rows. |
database_type | [R] | The type of database we are connecting to |
driver | [R] | The Java database driver we are using |
swift_class | [RW] | The Swift adapter class being used by this database. Connections in this database‘s connection pool will be instances of this class. |
Call the DATABASE_SETUP proc directly after initialization, so the object always uses sub adapter specific code. Also, raise an error immediately if the connection doesn‘t have a uri, since JDBC requires one.
# File lib/sequel/adapters/jdbc.rb, line 109 109: def initialize(opts) 110: super 111: @convert_types = typecast_value_boolean(@opts.fetch(:convert_types, true)) 112: raise(Error, "No connection string specified") unless uri 113: 114: resolved_uri = jndi? ? get_uri_from_jndi : uri 115: 116: if match = /\Ajdbc:([^:]+)/.match(resolved_uri) and prok = DATABASE_SETUP[match[1].to_sym] 117: @driver = prok.call(self) 118: end 119: end
Call the DATABASE_SETUP proc directly after initialization, so the object always uses sub adapter specific code. Also, raise an error immediately if the connection doesn‘t have a db_type specified, since one is required to include the correct subadapter.
# File lib/sequel/adapters/swift.rb, line 39 39: def initialize(opts) 40: super 41: if db_type = opts[:db_type] and !db_type.to_s.empty? 42: if prok = DATABASE_SETUP[db_type.to_s.to_sym] 43: prok.call(self) 44: else 45: raise(Error, "No :db_type option specified") 46: end 47: else 48: raise(Error, ":db_type option not valid, should be postgres or mysql") 49: end 50: end
Call the DATABASE_SETUP proc directly after initialization, so the object always uses sub adapter specific code. Also, raise an error immediately if the connection doesn‘t have a uri, since DataObjects requires one.
# File lib/sequel/adapters/do.rb, line 45 45: def initialize(opts) 46: super 47: raise(Error, "No connection string specified") unless uri 48: if prok = DATABASE_SETUP[subadapter.to_sym] 49: prok.call(self) 50: end 51: end
Execute the given stored procedure with the give name. If a block is given, the stored procedure should return rows.
# File lib/sequel/adapters/jdbc.rb, line 123 123: def call_sproc(name, opts = {}) 124: args = opts[:args] || [] 125: sql = "{call #{name}(#{args.map{'?'}.join(',')})}" 126: synchronize(opts[:server]) do |conn| 127: cps = conn.prepareCall(sql) 128: 129: i = 0 130: args.each{|arg| set_ps_arg(cps, arg, i+=1)} 131: 132: begin 133: if block_given? 134: yield log_yield(sql){cps.executeQuery} 135: else 136: case opts[:type] 137: when :insert 138: log_yield(sql){cps.executeUpdate} 139: last_insert_id(conn, opts) 140: else 141: log_yield(sql){cps.executeUpdate} 142: end 143: end 144: rescue NativeException, JavaSQL::SQLException => e 145: raise_error(e) 146: ensure 147: cps.close 148: end 149: end 150: end
Connect to the database using JavaSQL::DriverManager.getConnection.
# File lib/sequel/adapters/jdbc.rb, line 153 153: def connect(server) 154: opts = server_opts(server) 155: conn = if jndi? 156: get_connection_from_jndi 157: else 158: args = [uri(opts)] 159: args.concat([opts[:user], opts[:password]]) if opts[:user] && opts[:password] 160: begin 161: JavaSQL::DriverManager.getConnection(*args) 162: rescue => e 163: raise e unless driver 164: # If the DriverManager can't get the connection - use the connect 165: # method of the driver. (This happens under Tomcat for instance) 166: props = java.util.Properties.new 167: if opts && opts[:user] && opts[:password] 168: props.setProperty("user", opts[:user]) 169: props.setProperty("password", opts[:password]) 170: end 171: begin 172: driver.new.connect(args[0], props) 173: rescue => e2 174: e.message << "\n#{e2.class.name}: #{e2.message}" 175: raise e 176: end 177: end 178: end 179: setup_connection(conn) 180: end
Setup a DataObjects::Connection to the database.
# File lib/sequel/adapters/do.rb, line 54 54: def connect(server) 55: setup_connection(::DataObjects::Connection.new(uri(server_opts(server)))) 56: end
Create an instance of swift_class for the given options.
# File lib/sequel/adapters/swift.rb, line 53 53: def connect(server) 54: setup_connection(swift_class.new(server_opts(server))) 55: end
Connect to the database. In addition to the usual database options, the following options have effect:
# File lib/sequel/adapters/mysql.rb, line 120 120: def connect(server) 121: opts = server_opts(server) 122: conn = Mysql.init 123: conn.options(Mysql::READ_DEFAULT_GROUP, opts[:config_default_group] || "client") 124: conn.options(Mysql::OPT_LOCAL_INFILE, opts[:config_local_infile]) if opts.has_key?(:config_local_infile) 125: conn.ssl_set(opts[:sslkey], opts[:sslcert], opts[:sslca], opts[:sslcapath], opts[:sslcipher]) if opts[:sslca] || opts[:sslkey] 126: if encoding = opts[:encoding] || opts[:charset] 127: # Set encoding before connecting so that the mysql driver knows what 128: # encoding we want to use, but this can be overridden by READ_DEFAULT_GROUP. 129: conn.options(Mysql::SET_CHARSET_NAME, encoding) 130: end 131: if read_timeout = opts[:read_timeout] and Mysql::const_defined(Mysql::OPT_READ_TIMEOUT) 132: conn.options(Mysql::OPT_READ_TIMEOUT, read_timeout) 133: end 134: if connect_timeout = opts[:connect_timeout] and Mysql::const_defined(Mysql::OPT_CONNECT_TIMEOUT) 135: conn.options(Mysql::OPT_CONNECT_TIMEOUT, connect_timeout) 136: end 137: conn.real_connect( 138: opts[:host] || 'localhost', 139: opts[:user], 140: opts[:password], 141: opts[:database], 142: opts[:port], 143: opts[:socket], 144: Mysql::CLIENT_MULTI_RESULTS + 145: Mysql::CLIENT_MULTI_STATEMENTS + 146: (opts[:compress] == false ? 0 : Mysql::CLIENT_COMPRESS) 147: ) 148: sqls = [] 149: # Set encoding a slightly different way after connecting, 150: # in case the READ_DEFAULT_GROUP overrode the provided encoding. 151: # Doesn't work across implicit reconnects, but Sequel doesn't turn on 152: # that feature. 153: sqls << "SET NAMES #{literal(encoding.to_s)}" if encoding 154: 155: # Increase timeout so mysql server doesn't disconnect us 156: # Value used by default is maximum allowed value on Windows. 157: sqls << "SET @@wait_timeout = #{opts[:timeout] || 2147483}" 158: 159: # By default, MySQL 'where id is null' selects the last inserted id 160: sqls << "SET SQL_AUTO_IS_NULL=0" unless opts[:auto_is_null] 161: 162: sqls.each{|sql| log_yield(sql){conn.query(sql)}} 163: 164: class << conn 165: attr_accessor :prepared_statements 166: end 167: conn.prepared_statements = {} 168: conn 169: end
Connect to the database. Since SQLite is a file based database, the only options available are :database (to specify the database name), and :timeout, to specify how long to wait for the database to be available if it is locked, given in milliseconds (default is 5000).
# File lib/sequel/adapters/sqlite.rb, line 59 59: def connect(server) 60: opts = server_opts(server) 61: opts[:database] = ':memory:' if blank_object?(opts[:database]) 62: db = ::SQLite3::Database.new(opts[:database]) 63: db.busy_timeout(opts.fetch(:timeout, 5000)) 64: 65: connection_pragmas.each{|s| log_yield(s){db.execute_batch(s)}} 66: 67: class << db 68: attr_reader :prepared_statements 69: end 70: db.instance_variable_set(:@prepared_statements, {}) 71: 72: db 73: end
Connects to the database. In addition to the standard database options, using the :encoding or :charset option changes the client encoding for the connection.
# File lib/sequel/adapters/postgres.rb, line 209 209: def connect(server) 210: opts = server_opts(server) 211: conn = Adapter.connect( 212: (opts[:host] unless blank_object?(opts[:host])), 213: opts[:port] || 5432, 214: nil, '', 215: opts[:database], 216: opts[:user], 217: opts[:password] 218: ) 219: if encoding = opts[:encoding] || opts[:charset] 220: if conn.respond_to?(:set_client_encoding) 221: conn.set_client_encoding(encoding) 222: else 223: conn.async_exec("set client_encoding to '#{encoding}'") 224: end 225: end 226: conn.db = self 227: conn.apply_connection_settings 228: conn 229: end
Return instance of Sequel::Postgres::Dataset with the given options.
# File lib/sequel/adapters/postgres.rb, line 232 232: def dataset(opts = nil) 233: Postgres::Dataset.new(self, opts) 234: end
Return a Sequel::Swift::Dataset object for this database.
# File lib/sequel/adapters/swift.rb, line 58 58: def dataset(opts = nil) 59: Swift::Dataset.new(self, opts) 60: end
Return a Sequel::DataObjects::Dataset object for this database.
# File lib/sequel/adapters/do.rb, line 59 59: def dataset(opts = nil) 60: DataObjects::Dataset.new(self, opts) 61: end
Returns instance of Sequel::MySQL::Dataset with the given options.
# File lib/sequel/adapters/mysql.rb, line 172 172: def dataset(opts = nil) 173: MySQL::Dataset.new(self, opts) 174: end
Return instances of JDBC::Dataset with the given opts.
# File lib/sequel/adapters/jdbc.rb, line 183 183: def dataset(opts = nil) 184: JDBC::Dataset.new(self, opts) 185: end
Return instance of Sequel::SQLite::Dataset with the given options.
# File lib/sequel/adapters/sqlite.rb, line 76 76: def dataset(opts = nil) 77: SQLite::Dataset.new(self, opts) 78: end
Execute the given SQL, yielding a Swift::Result if a block is given.
# File lib/sequel/adapters/swift.rb, line 63 63: def execute(sql, opts={}) 64: synchronize(opts[:server]) do |conn| 65: begin 66: res = nil 67: log_yield(sql){conn.execute(sql); res = conn.results} 68: yield res if block_given? 69: nil 70: rescue SwiftError => e 71: raise_error(e) 72: ensure 73: res.finish if res 74: end 75: end 76: end
Execute the given SQL. If a block is given, if should be a SELECT statement or something else that returns rows.
# File lib/sequel/adapters/jdbc.rb, line 189 189: def execute(sql, opts={}, &block) 190: return call_sproc(sql, opts, &block) if opts[:sproc] 191: return execute_prepared_statement(sql, opts, &block) if [Symbol, Dataset].any?{|c| sql.is_a?(c)} 192: synchronize(opts[:server]) do |conn| 193: statement(conn) do |stmt| 194: if block 195: yield log_yield(sql){stmt.executeQuery(sql)} 196: else 197: case opts[:type] 198: when :ddl 199: log_yield(sql){stmt.execute(sql)} 200: when :insert 201: log_yield(sql) do 202: if requires_return_generated_keys? 203: stmt.executeUpdate(sql, JavaSQL::Statement.RETURN_GENERATED_KEYS) 204: else 205: stmt.executeUpdate(sql) 206: end 207: end 208: last_insert_id(conn, opts.merge(:stmt=>stmt)) 209: else 210: log_yield(sql){stmt.executeUpdate(sql)} 211: end 212: end 213: end 214: end 215: end
Execute the given SQL. If a block is given, the DataObjects::Reader created is yielded to it. A block should not be provided unless a a SELECT statement is being used (or something else that returns rows). Otherwise, the return value is the insert id if opts[:type] is :insert, or the number of affected rows, otherwise.
# File lib/sequel/adapters/do.rb, line 68 68: def execute(sql, opts={}) 69: synchronize(opts[:server]) do |conn| 70: begin 71: command = conn.create_command(sql) 72: res = log_yield(sql){block_given? ? command.execute_reader : command.execute_non_query} 73: rescue ::DataObjects::Error => e 74: raise_error(e) 75: end 76: if block_given? 77: begin 78: yield(res) 79: ensure 80: res.close if res 81: end 82: elsif opts[:type] == :insert 83: res.insert_id 84: else 85: res.affected_rows 86: end 87: end 88: end
Executes the given SQL using an available connection, yielding the connection if the block is given.
# File lib/sequel/adapters/mysql.rb, line 178 178: def execute(sql, opts={}, &block) 179: if opts[:sproc] 180: call_sproc(sql, opts, &block) 181: elsif sql.is_a?(Symbol) 182: execute_prepared_statement(sql, opts, &block) 183: else 184: synchronize(opts[:server]){|conn| _execute(conn, sql, opts, &block)} 185: end 186: end
Execute the given SQL with the given args on an available connection.
# File lib/sequel/adapters/postgres.rb, line 237 237: def execute(sql, opts={}, &block) 238: check_database_errors do 239: return execute_prepared_statement(sql, opts, &block) if Symbol === sql 240: synchronize(opts[:server]){|conn| conn.execute(sql, opts[:arguments], &block)} 241: end 242: end
Drop any prepared statements on the connection when executing DDL. This is because prepared statements lock the table in such a way that you can‘t drop or alter the table while a prepared statement that references it still exists.
# File lib/sequel/adapters/sqlite.rb, line 93 93: def execute_ddl(sql, opts={}) 94: synchronize(opts[:server]) do |conn| 95: conn.prepared_statements.values.each{|cps, s| cps.close} 96: conn.prepared_statements.clear 97: super 98: end 99: end
Execute the SQL on the this database, returning the number of affected rows.
# File lib/sequel/adapters/swift.rb, line 80 80: def execute_dui(sql, opts={}) 81: synchronize(opts[:server]) do |conn| 82: begin 83: log_yield(sql){conn.execute(sql)} 84: rescue SwiftError => e 85: raise_error(e) 86: end 87: end 88: end
Insert the values into the table and return the primary key (if automatically generated).
# File lib/sequel/adapters/postgres.rb, line 246 246: def execute_insert(sql, opts={}) 247: return execute(sql, opts) if Symbol === sql 248: check_database_errors do 249: synchronize(opts[:server]) do |conn| 250: conn.execute(sql, opts[:arguments]) 251: insert_result(conn, opts[:table], opts[:values]) 252: end 253: end 254: end
Execute the SQL on this database, returning the primary key of the table being inserted to.
# File lib/sequel/adapters/swift.rb, line 92 92: def execute_insert(sql, opts={}) 93: synchronize(opts[:server]) do |conn| 94: begin 95: res = nil 96: log_yield(sql){conn.execute(sql); (res = conn.results).insert_id} 97: rescue SwiftError => e 98: raise_error(e) 99: ensure 100: res.finish if res 101: end 102: end 103: end
Use the JDBC metadata to get the index information for the table.
# File lib/sequel/adapters/jdbc.rb, line 231 231: def indexes(table, opts={}) 232: m = output_identifier_meth 233: im = input_identifier_meth 234: schema, table = schema_and_table(table) 235: schema ||= opts[:schema] 236: schema = im.call(schema) if schema 237: table = im.call(table) 238: indexes = {} 239: metadata(:getIndexInfo, nil, schema, table, false, true) do |r| 240: next unless name = r[:column_name] 241: next if respond_to?(:primary_key_index_re, true) and r[:index_name] =~ primary_key_index_re 242: i = indexes[m.call(r[:index_name])] ||= {:columns=>[], :unique=>[false, 0].include?(r[:non_unique])} 243: i[:columns] << m.call(name) 244: end 245: indexes 246: end
Whether or not JNDI is being used for this connection.
# File lib/sequel/adapters/jdbc.rb, line 267 267: def jndi? 268: !!(uri =~ JNDI_URI_REGEXP) 269: end
Return the subadapter type for this database, i.e. sqlite3 for do:sqlite3::memory:.
# File lib/sequel/adapters/do.rb, line 104 104: def subadapter 105: uri.split(":").first 106: end
Return the DataObjects URI for the Sequel URI, removing the do: prefix.
# File lib/sequel/adapters/do.rb, line 110 110: def uri(opts={}) 111: opts = @opts.merge(opts) 112: (opts[:uri] || opts[:url]).sub(/\Ado:/, '') 113: end
The uri for this connection. You can specify the uri using the :uri, :url, or :database options. You don‘t need to worry about this if you use Sequel.connect with the JDBC connectrion strings.
# File lib/sequel/adapters/jdbc.rb, line 260 260: def uri(opts={}) 261: opts = @opts.merge(opts) 262: ur = opts[:uri] || opts[:url] || opts[:database] 263: ur =~ /^\Ajdbc:/ ? ur : "jdbc:#{ur}" 264: end
AUTOINCREMENT | = | 'AUTOINCREMENT'.freeze |
CASCADE | = | 'CASCADE'.freeze |
COMMA_SEPARATOR | = | ', '.freeze |
NO_ACTION | = | 'NO ACTION'.freeze |
NOT_NULL | = | ' NOT NULL'.freeze |
NULL | = | ' NULL'.freeze |
PRIMARY_KEY | = | ' PRIMARY KEY'.freeze |
RESTRICT | = | 'RESTRICT'.freeze |
SET_DEFAULT | = | 'SET DEFAULT'.freeze |
SET_NULL | = | 'SET NULL'.freeze |
TEMPORARY | = | 'TEMPORARY '.freeze |
UNDERSCORE | = | '_'.freeze |
UNIQUE | = | ' UNIQUE'.freeze |
UNSIGNED | = | ' UNSIGNED'.freeze |
Adds a column to the specified table. This method expects a column name, a datatype and optionally a hash with additional constraints and options:
DB.add_column :items, :name, :text, :unique => true, :null => false DB.add_column :items, :category, :text, :default => 'ruby'
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 30 30: def add_column(table, *args) 31: alter_table(table) {add_column(*args)} 32: end
Adds an index to a table for the given columns:
DB.add_index :posts, :title DB.add_index :posts, [:author, :title], :unique => true
Options:
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 43 43: def add_index(table, columns, options={}) 44: e = options[:ignore_errors] 45: begin 46: alter_table(table){add_index(columns, options)} 47: rescue DatabaseError 48: raise unless e 49: end 50: end
Alters the given table with the specified block. Example:
DB.alter_table :items do add_column :category, :text, :default => 'ruby' drop_column :category rename_column :cntr, :counter set_column_type :value, :float set_column_default :value, :float add_index [:group, :category] drop_index [:group, :category] end
Note that add_column accepts all the options available for column definitions using create_table, and add_index accepts all the options available for index definition.
See Schema::AlterTableGenerator and the "Migrations and Schema Modification" guide.
# File lib/sequel/database/schema_methods.rb, line 69 69: def alter_table(name, generator=nil, &block) 70: generator ||= Schema::AlterTableGenerator.new(self, &block) 71: alter_table_sql_list(name, generator.operations).flatten.each {|sql| execute_ddl(sql)} 72: remove_cached_schema(name) 73: nil 74: end
Creates a view, replacing it if it already exists:
DB.create_or_replace_view(:cheap_items, "SELECT * FROM items WHERE price < 100") DB.create_or_replace_view(:ruby_items, DB[:items].filter(:category => 'ruby'))
# File lib/sequel/database/schema_methods.rb, line 118 118: def create_or_replace_view(name, source) 119: source = source.sql if source.is_a?(Dataset) 120: execute_ddl("CREATE OR REPLACE VIEW #{quote_schema_table(name)} AS #{source}") 121: remove_cached_schema(name) 122: nil 123: end
Creates a table with the columns given in the provided block:
DB.create_table :posts do primary_key :id column :title, :text String :content index :title end
Options:
:temp : | Create the table as a temporary table. |
:ignore_index_errors : | Ignore any errors when creating indexes. |
See Schema::Generator and the "Migrations and Schema Modification" guide.
# File lib/sequel/database/schema_methods.rb, line 90 90: def create_table(name, options={}, &block) 91: remove_cached_schema(name) 92: options = {:generator=>options} if options.is_a?(Schema::Generator) 93: generator = options[:generator] || Schema::Generator.new(self, &block) 94: create_table_from_generator(name, generator, options) 95: create_table_indexes_from_generator(name, generator, options) 96: nil 97: end
Forcibly creates a table, attempting to drop it unconditionally (and catching any errors), then creating it.
DB.create_table!(:a){Integer :a} # DROP TABLE a # CREATE TABLE a (a integer)
# File lib/sequel/database/schema_methods.rb, line 104 104: def create_table!(name, options={}, &block) 105: drop_table(name) rescue nil 106: create_table(name, options, &block) 107: end
Creates the table unless the table already exists
# File lib/sequel/database/schema_methods.rb, line 110 110: def create_table?(name, options={}, &block) 111: create_table(name, options, &block) unless table_exists?(name) 112: end
Creates a view based on a dataset or an SQL string:
DB.create_view(:cheap_items, "SELECT * FROM items WHERE price < 100") DB.create_view(:ruby_items, DB[:items].filter(:category => 'ruby'))
# File lib/sequel/database/schema_methods.rb, line 129 129: def create_view(name, source) 130: source = source.sql if source.is_a?(Dataset) 131: execute_ddl("CREATE VIEW #{quote_schema_table(name)} AS #{source}") 132: end
Removes a column from the specified table:
DB.drop_column :items, :category
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 139 139: def drop_column(table, *args) 140: alter_table(table) {drop_column(*args)} 141: end
Removes an index for the given table and column/s:
DB.drop_index :posts, :title DB.drop_index :posts, [:author, :title]
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 149 149: def drop_index(table, columns, options={}) 150: alter_table(table){drop_index(columns, options)} 151: end
Drops one or more views corresponding to the given names:
DB.drop_view(:cheap_items)
# File lib/sequel/database/schema_methods.rb, line 167 167: def drop_view(*names) 168: names.each do |n| 169: execute_ddl("DROP VIEW #{quote_schema_table(n)}") 170: remove_cached_schema(n) 171: end 172: nil 173: end
Renames a column in the specified table. This method expects the current column name and the new column name:
DB.rename_column :items, :cntr, :counter
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 192 192: def rename_column(table, *args) 193: alter_table(table) {rename_column(*args)} 194: end
Renames a table:
DB.tables #=> [:items] DB.rename_table :items, :old_items DB.tables #=> [:old_items]
# File lib/sequel/database/schema_methods.rb, line 180 180: def rename_table(name, new_name) 181: execute_ddl(rename_table_sql(name, new_name)) 182: remove_cached_schema(name) 183: nil 184: end
Sets the default value for the given column in the given table:
DB.set_column_default :items, :category, 'perl!'
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 201 201: def set_column_default(table, *args) 202: alter_table(table) {set_column_default(*args)} 203: end
Set the data type for the given column in the given table:
DB.set_column_type :items, :price, :float
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 210 210: def set_column_type(table, *args) 211: alter_table(table) {set_column_type(*args)} 212: end
This methods involve the Database‘s connection pool.
ADAPTERS | = | %w'ado amalgalite db2 dbi do firebird informix jdbc mysql mysql2 odbc openbase oracle postgres sqlite swift'.collect{|x| x.to_sym} | Array of supported database adapters |
The Database subclass for the given adapter scheme. Raises Sequel::AdapterNotFound if the adapter could not be loaded.
# File lib/sequel/database/connecting.rb, line 17 17: def self.adapter_class(scheme) 18: return scheme if scheme.is_a?(Class) 19: 20: scheme = scheme.to_s.gsub('-', '_').to_sym 21: 22: unless klass = ADAPTER_MAP[scheme] 23: # attempt to load the adapter file 24: begin 25: Sequel.tsk_require "sequel/adapters/#{scheme}" 26: rescue LoadError => e 27: raise Sequel.convert_exception_class(e, AdapterNotFound) 28: end 29: 30: # make sure we actually loaded the adapter 31: unless klass = ADAPTER_MAP[scheme] 32: raise AdapterNotFound, "Could not load #{scheme} adapter: adapter class not registered in ADAPTER_MAP" 33: end 34: end 35: klass 36: end
Connects to a database. See Sequel.connect.
# File lib/sequel/database/connecting.rb, line 44 44: def self.connect(conn_string, opts = {}) 45: case conn_string 46: when String 47: if match = /\A(jdbc|do):/o.match(conn_string) 48: c = adapter_class(match[1].to_sym) 49: opts = {:uri=>conn_string}.merge(opts) 50: else 51: uri = URI.parse(conn_string) 52: scheme = uri.scheme 53: scheme = :dbi if scheme =~ /\Adbi-/ 54: c = adapter_class(scheme) 55: uri_options = c.send(:uri_to_options, uri) 56: uri.query.split('&').collect{|s| s.split('=')}.each{|k,v| uri_options[k.to_sym] = v if k && !k.empty?} unless uri.query.to_s.strip.empty? 57: uri_options.entries.each{|k,v| uri_options[k] = URI.unescape(v) if v.is_a?(String)} 58: opts = uri_options.merge(opts) 59: opts[:adapter] = scheme 60: end 61: when Hash 62: opts = conn_string.merge(opts) 63: c = adapter_class(opts[:adapter_class] || opts[:adapter] || opts['adapter']) 64: else 65: raise Error, "Sequel::Database.connect takes either a Hash or a String, given: #{conn_string.inspect}" 66: end 67: # process opts a bit 68: opts = opts.inject({}) do |m, (k,v)| 69: k = :user if k.to_s == 'username' 70: m[k.to_sym] = v 71: m 72: end 73: begin 74: db = c.new(opts) 75: db.test_connection if opts[:test] && db.send(:typecast_value_boolean, opts[:test]) 76: result = yield(db) if block_given? 77: ensure 78: if block_given? 79: db.disconnect if db 80: ::Sequel::DATABASES.delete(db) 81: end 82: end 83: block_given? ? result : db 84: end
Returns the scheme symbol for this instance‘s class, which reflects which adapter is being used. In some cases, this can be the same as the database_type (for native adapters), in others (i.e. adapters with subadapters), it will be different.
Sequel.connect('jdbc:postgres://...').adapter_scheme # => :jdbc
# File lib/sequel/database/connecting.rb, line 120 120: def adapter_scheme 121: self.class.adapter_scheme 122: end
Dynamically add new servers or modify server options at runtime. Also adds new servers to the connection pool. Intended for use with master/slave or shard configurations where it is useful to add new server hosts at runtime.
servers argument should be a hash with server name symbol keys and hash or proc values. If a servers key is already in use, it‘s value is overridden with the value provided.
DB.add_servers(:f=>{:host=>"hash_host_f"})
# File lib/sequel/database/connecting.rb, line 133 133: def add_servers(servers) 134: @opts[:servers] = @opts[:servers] ? @opts[:servers].merge(servers) : servers 135: @pool.add_servers(servers.keys) 136: end
Connects to the database. This method should be overridden by descendants.
# File lib/sequel/database/connecting.rb, line 139 139: def connect(server) 140: raise NotImplemented, "#connect should be overridden by adapters" 141: end
The database type for this database object, the same as the adapter scheme by default. Should be overridden in adapters (especially shared adapters) to be the correct type, so that even if two separate Database objects are using different adapters you can tell that they are using the same database type. Even better, you can tell that two Database objects that are using the same adapter are connecting to different database types (think JDBC or DataObjects).
Sequel.connect('jdbc:postgres://...').database_type # => :postgres
# File lib/sequel/database/connecting.rb, line 152 152: def database_type 153: adapter_scheme 154: end
Disconnects all available connections from the connection pool. Any connections currently in use will not be disconnected. Options:
Example:
DB.disconnect # All servers DB.disconnect(:servers=>:server1) # Single server DB.disconnect(:servers=>[:server1, :server2]) # Multiple servers
# File lib/sequel/database/connecting.rb, line 166 166: def disconnect(opts = {}) 167: pool.disconnect(opts) 168: end
Yield a new Database instance for every server in the connection pool. Intended for use in sharded environments where there is a need to make schema modifications (DDL queries) on each shard.
DB.each_server{|db| db.create_table(:users){primary_key :id; String :name}}
# File lib/sequel/database/connecting.rb, line 175 175: def each_server(&block) 176: servers.each{|s| self.class.connect(server_opts(s), &block)} 177: end
Dynamically remove existing servers from the connection pool. Intended for use with master/slave or shard configurations where it is useful to remove existing server hosts at runtime.
servers should be symbols or arrays of symbols. If a nonexistent server is specified, it is ignored. If no servers have been specified for this database, no changes are made. If you attempt to remove the :default server, an error will be raised.
DB.remove_servers(:f1, :f2)
# File lib/sequel/database/connecting.rb, line 189 189: def remove_servers(*servers) 190: if @opts[:servers] && !@opts[:servers].empty? 191: servs = @opts[:servers].dup 192: servers.flatten! 193: servers.each{|s| servs.delete(s)} 194: @opts[:servers] = servs 195: @pool.remove_servers(servers) 196: end 197: end
Returns true if the database is using a single-threaded connection pool.
# File lib/sequel/database/connecting.rb, line 208 208: def single_threaded? 209: @single_threaded 210: end
Acquires a database connection, yielding it to the passed block. This is useful if you want to make sure the same connection is used for all database queries in the block. It is also useful if you want to gain direct access to the underlying connection object if you need to do something Sequel does not natively support.
If a server option is given, acquires a connection for that specific server, instead of the :default server.
DB.synchronize do |conn| ... end
# File lib/sequel/database/connecting.rb, line 225 225: def synchronize(server=nil, &block) 226: @pool.hold(server || :default, &block) 227: end
Attempts to acquire a database connection. Returns true if successful. Will probably raise an Error if unsuccessful. If a server argument is given, attempts to acquire a database connection to the given server/shard.
# File lib/sequel/database/connecting.rb, line 233 233: def test_connection(server=nil) 234: synchronize(server){|conn|} 235: true 236: end
These methods all return instances of this database‘s dataset class.
Returns a dataset for the database. If the first argument is a string, the method acts as an alias for Database#fetch, returning a dataset for arbitrary SQL, with or without placeholders:
DB['SELECT * FROM items'].all DB['SELECT * FROM items WHERE name = ?', my_name].all
Otherwise, acts as an alias for Database#from, setting the primary table for the dataset:
DB[:items].sql #=> "SELECT * FROM items"
# File lib/sequel/database/dataset.rb, line 19 19: def [](*args) 20: (String === args.first) ? fetch(*args) : from(*args) 21: end
Fetches records for an arbitrary SQL statement. If a block is given, it is used to iterate over the records:
DB.fetch('SELECT * FROM items'){|r| p r}
The fetch method returns a dataset instance:
DB.fetch('SELECT * FROM items').all
fetch can also perform parameterized queries for protection against SQL injection:
DB.fetch('SELECT * FROM items WHERE name = ?', my_name).all
# File lib/sequel/database/dataset.rb, line 44 44: def fetch(sql, *args, &block) 45: ds = dataset.with_sql(sql, *args) 46: ds.each(&block) if block 47: ds 48: end
Returns a new dataset with the from method invoked. If a block is given, it is used as a filter on the dataset.
DB.from(:items) # SELECT * FROM items DB.from(:items){id > 2} # SELECT * FROM items WHERE (id > 2)
# File lib/sequel/database/dataset.rb, line 55 55: def from(*args, &block) 56: ds = dataset.from(*args) 57: block ? ds.filter(&block) : ds 58: end
Returns a new dataset with the select method invoked.
DB.select(1) # SELECT 1 DB.select{server_version{}} # SELECT server_version() DB.select(:id).from(:items) # SELECT id FROM items
# File lib/sequel/database/dataset.rb, line 65 65: def select(*args, &block) 66: dataset.select(*args, &block) 67: end
This methods change the default behavior of this database‘s datasets.
default_schema | [RW] | The default schema to use, generally should be nil. |
The method to call on identifiers going into the database
# File lib/sequel/database/dataset_defaults.rb, line 49 49: def identifier_input_method 50: case @identifier_input_method 51: when nil 52: @identifier_input_method = @opts.fetch(:identifier_input_method, (@@identifier_input_method.nil? ? identifier_input_method_default : @@identifier_input_method)) 53: @identifier_input_method == "" ? nil : @identifier_input_method 54: when "" 55: nil 56: else 57: @identifier_input_method 58: end 59: end
Set the method to call on identifiers going into the database:
DB[:items] # SELECT * FROM items DB.identifier_input_method = :upcase DB[:items] # SELECT * FROM ITEMS
# File lib/sequel/database/dataset_defaults.rb, line 66 66: def identifier_input_method=(v) 67: reset_schema_utility_dataset 68: @identifier_input_method = v || "" 69: end
The method to call on identifiers coming from the database
# File lib/sequel/database/dataset_defaults.rb, line 72 72: def identifier_output_method 73: case @identifier_output_method 74: when nil 75: @identifier_output_method = @opts.fetch(:identifier_output_method, (@@identifier_output_method.nil? ? identifier_output_method_default : @@identifier_output_method)) 76: @identifier_output_method == "" ? nil : @identifier_output_method 77: when "" 78: nil 79: else 80: @identifier_output_method 81: end 82: end
Set the method to call on identifiers coming from the database:
DB[:items].first # {:id=>1, :name=>'foo'} DB.identifier_output_method = :upcase DB[:items].first # {:ID=>1, :NAME=>'foo'}
# File lib/sequel/database/dataset_defaults.rb, line 89 89: def identifier_output_method=(v) 90: reset_schema_utility_dataset 91: @identifier_output_method = v || "" 92: end
Set whether to quote identifiers (columns and tables) for this database:
DB[:items] # SELECT * FROM items DB.quote_identifiers = true DB[:items] # SELECT * FROM "items"
# File lib/sequel/database/dataset_defaults.rb, line 99 99: def quote_identifiers=(v) 100: reset_schema_utility_dataset 101: @quote_identifiers = v 102: end
Returns true if the database quotes identifiers.
# File lib/sequel/database/dataset_defaults.rb, line 105 105: def quote_identifiers? 106: return @quote_identifiers unless @quote_identifiers.nil? 107: @quote_identifiers = @opts.fetch(:quote_identifiers, (@@quote_identifiers.nil? ? quote_identifiers_default : @@quote_identifiers)) 108: end
This methods affect relating to the logging of executed SQL.
log_warn_duration | [RW] | Numeric specifying the duration beyond which queries are logged at warn level instead of info level. |
loggers | [RW] | Array of SQL loggers to use for this database. |
sql_log_level | [RW] | Log level at which to log SQL queries. This is actually the method sent to the logger, so it should be the method name symbol. The default is :info, it can be set to :debug to log at DEBUG level. |
Log a message at level info to all loggers.
# File lib/sequel/database/logging.rb, line 21 21: def log_info(message, args=nil) 22: log_each(:info, args ? "#{message}; #{args.inspect}" : message) 23: end
Yield to the block, logging any errors at error level to all loggers, and all other queries with the duration at warn or info level.
# File lib/sequel/database/logging.rb, line 27 27: def log_yield(sql, args=nil) 28: return yield if @loggers.empty? 29: sql = "#{sql}; #{args.inspect}" if args 30: start = Time.now 31: begin 32: yield 33: rescue => e 34: log_each(:error, "#{e.class}: #{e.message.strip}: #{sql}") 35: raise 36: ensure 37: log_duration(Time.now - start, sql) unless e 38: end 39: end
These methods don‘t fit neatly into another category.
opts | [R] | The options hash for this database |
Constructs a new instance of a database connection with the specified options hash.
Accepts the following options:
:default_schema : | The default schema to use, should generally be nil |
:disconnection_proc : | A proc used to disconnect the connection |
:identifier_input_method : | A string method symbol to call on identifiers going into the database |
:identifier_output_method : | A string method symbol to call on identifiers coming from the database |
:logger : | A specific logger to use |
:loggers : | An array of loggers to use |
:quote_identifiers : | Whether to quote identifiers |
:servers : | A hash specifying a server/shard specific options, keyed by shard symbol |
:single_threaded : | Whether to use a single-threaded connection pool |
:sql_log_level : | Method to use to log SQL to a logger, :info by default. |
All options given are also passed to the connection pool. If a block is given, it is used as the connection_proc for the ConnectionPool.
# File lib/sequel/database/misc.rb, line 39 39: def initialize(opts = {}, &block) 40: @opts ||= opts 41: @opts = connection_pool_default_options.merge(@opts) 42: @loggers = Array(@opts[:logger]) + Array(@opts[:loggers]) 43: self.log_warn_duration = @opts[:log_warn_duration] 44: @opts[:disconnection_proc] ||= proc{|conn| disconnect_connection(conn)} 45: block ||= proc{|server| connect(server)} 46: @opts[:servers] = {} if @opts[:servers].is_a?(String) 47: @opts[:adapter_class] = self.class 48: 49: @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, @@single_threaded)) 50: @schemas = {} 51: @default_schema = @opts.fetch(:default_schema, default_schema_default) 52: @prepared_statements = {} 53: @transactions = [] 54: @identifier_input_method = nil 55: @identifier_output_method = nil 56: @quote_identifiers = nil 57: self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info 58: @pool = ConnectionPool.get_pool(@opts, &block) 59: 60: ::Sequel::DATABASES.push(self) 61: end
Returns a string representation of the database object including the class name and the connection URI (or the opts if the URI cannot be constructed).
# File lib/sequel/database/misc.rb, line 74 74: def inspect 75: "#<#{self.class}: #{(uri rescue opts).inspect}>" 76: end
Default serial primary key options, used by the table creation code.
# File lib/sequel/database/misc.rb, line 89 89: def serial_primary_key_options 90: {:primary_key => true, :type => Integer, :auto_increment => true} 91: end
Whether the database and adapter support prepared transactions (two-phase commit), false by default.
# File lib/sequel/database/misc.rb, line 95 95: def supports_prepared_transactions? 96: false 97: end
Whether the database and adapter support savepoints, false by default.
# File lib/sequel/database/misc.rb, line 100 100: def supports_savepoints? 101: false 102: end
Whether the database and adapter support transaction isolation levels, false by default.
# File lib/sequel/database/misc.rb, line 105 105: def supports_transaction_isolation_levels? 106: false 107: end
Typecast the value to the given column_type. Calls typecast_value_#{column_type} if the method exists, otherwise returns the value. This method should raise Sequel::InvalidValue if assigned value is invalid.
# File lib/sequel/database/misc.rb, line 114 114: def typecast_value(column_type, value) 115: return nil if value.nil? 116: meth = "typecast_value_#{column_type}" 117: begin 118: respond_to?(meth, true) ? send(meth, value) : value 119: rescue ArgumentError, TypeError => e 120: raise Sequel.convert_exception_class(e, InvalidValue) 121: end 122: end
Returns the URI identifying the database, which may not be the same as the URI used when connecting. This method can raise an error if the database used options instead of a connection string, and will not include uri parameters.
Sequel.connect('postgres://localhost/db?user=billg').url # => "postgres://billg@localhost/db"
# File lib/sequel/database/misc.rb, line 132 132: def uri 133: uri = URI::Generic.new( 134: adapter_scheme.to_s, 135: nil, 136: @opts[:host], 137: @opts[:port], 138: nil, 139: "/#{@opts[:database]}", 140: nil, 141: nil, 142: nil 143: ) 144: uri.user = @opts[:user] 145: uri.password = @opts[:password] if uri.user 146: uri.to_s 147: end
SQL_BEGIN | = | 'BEGIN'.freeze |
SQL_COMMIT | = | 'COMMIT'.freeze |
SQL_RELEASE_SAVEPOINT | = | 'RELEASE SAVEPOINT autopoint_%d'.freeze |
SQL_ROLLBACK | = | 'ROLLBACK'.freeze |
SQL_ROLLBACK_TO_SAVEPOINT | = | 'ROLLBACK TO SAVEPOINT autopoint_%d'.freeze |
SQL_SAVEPOINT | = | 'SAVEPOINT autopoint_%d'.freeze |
TRANSACTION_BEGIN | = | 'Transaction.begin'.freeze |
TRANSACTION_COMMIT | = | 'Transaction.commit'.freeze |
TRANSACTION_ROLLBACK | = | 'Transaction.rollback'.freeze |
TRANSACTION_ISOLATION_LEVELS | = | {:uncommitted=>'READ UNCOMMITTED'.freeze, :committed=>'READ COMMITTED'.freeze, :repeatable=>'REPEATABLE READ'.freeze, :serializable=>'SERIALIZABLE'.freeze} |
POSTGRES_DEFAULT_RE | = | /\A(?:B?('.*')::[^']+|\((-?\d+(?:\.\d+)?)\))\z/ |
MSSQL_DEFAULT_RE | = | /\A(?:\(N?('.*')\)|\(\((-?\d+(?:\.\d+)?)\)\))\z/ |
MYSQL_TIMESTAMP_RE | = | /\ACURRENT_(?:DATE|TIMESTAMP)?\z/ |
STRING_DEFAULT_RE | = | /\A'(.*)'\z/ |
prepared_statements | [R] | The prepared statement object hash for this database, keyed by name symbol |
transaction_isolation_level | [RW] | The default transaction isolation level for this database, used for all future transactions. For MSSQL, this should be set to something if you ever plan to use the :isolation option to Database#transaction, as on MSSQL if affects all future transactions on the same connection. |
Call the prepared statement with the given name with the given hash of arguments.
DB[:items].filter(:id=>1).prepare(:first, :sa) DB.call(:sa) # SELECT * FROM items WHERE id = 1
# File lib/sequel/database/query.rb, line 50 50: def call(ps_name, hash={}) 51: prepared_statements[ps_name].call(hash) 52: end
Dump indexes for all tables as a migration. This complements the :indexes=>false option to dump_schema_migration. Options:
# File lib/sequel/extensions/schema_dumper.rb, line 13 13: def dump_indexes_migration(options={}) 14: ts = tables(options) 15: "Sequel.migration do\n up do\n\#{ts.sort_by{|t| t.to_s}.map{|t| dump_table_indexes(t, :add_index, options)}.reject{|x| x == ''}.join(\"\\n\\n\").gsub(/^/o, ' ')}\n end\n \n down do\n\#{ts.sort_by{|t| t.to_s}.map{|t| dump_table_indexes(t, :drop_index, options)}.reject{|x| x == ''}.join(\"\\n\\n\").gsub(/^/o, ' ')}\n end\nend\n" 16: end
Return a string that contains a Sequel::Migration subclass that when run would recreate the database structure. Options:
# File lib/sequel/extensions/schema_dumper.rb, line 38 38: def dump_schema_migration(options={}) 39: ts = tables(options) 40: "Sequel.migration do\n up do\n\#{ts.sort_by{|t| t.to_s}.map{|t| dump_table_schema(t, options)}.join(\"\\n\\n\").gsub(/^/o, ' ')}\n end\n \n down do\n drop_table(\#{ts.sort_by{|t| t.to_s}.inspect[1...-1]})\n end\nend\n" 41: end
Return a string with a create table block that will recreate the given table‘s schema. Takes the same options as dump_schema_migration.
# File lib/sequel/extensions/schema_dumper.rb, line 56 56: def dump_table_schema(table, options={}) 57: table = table.value.to_s if table.is_a?(SQL::Identifier) 58: raise(Error, "must provide table as a Symbol, String, or Sequel::SQL::Identifier") unless [String, Symbol].any?{|c| table.is_a?(c)} 59: s = schema(table).dup 60: pks = s.find_all{|x| x.last[:primary_key] == true}.map{|x| x.first} 61: options = options.merge(:single_pk=>true) if pks.length == 1 62: m = method(:column_schema_to_generator_opts) 63: im = method(:index_to_generator_opts) 64: begin 65: indexes = indexes(table).sort_by{|k,v| k.to_s} if options[:indexes] != false 66: rescue Sequel::NotImplemented 67: nil 68: end 69: gen = Schema::Generator.new(self) do 70: s.each{|name, info| send(*m.call(name, info, options))} 71: primary_key(pks) if !@primary_key && pks.length > 0 72: indexes.each{|iname, iopts| send(:index, iopts[:columns], im.call(table, iname, iopts))} if indexes 73: end 74: commands = [gen.dump_columns, gen.dump_constraints, gen.dump_indexes].reject{|x| x == ''}.join("\n\n") 75: "create_table(#{table.inspect}#{', :ignore_index_errors=>true' if !options[:same_db] && options[:indexes] != false && indexes && !indexes.empty?}) do\n#{commands.gsub(/^/o, ' ')}\nend" 76: end
Executes the given SQL on the database. This method should be overridden in descendants. This method should not be called directly by user code.
# File lib/sequel/database/query.rb, line 56 56: def execute(sql, opts={}) 57: raise NotImplemented, "#execute should be overridden by adapters" 58: end
Method that should be used when submitting any DDL (Data Definition Language) SQL, such as create_table. By default, calls execute_dui. This method should not be called directly by user code.
# File lib/sequel/database/query.rb, line 63 63: def execute_ddl(sql, opts={}, &block) 64: execute_dui(sql, opts, &block) 65: end
Method that should be used when issuing a INSERT statement. By default, calls execute_dui. This method should not be called directly by user code.
# File lib/sequel/database/query.rb, line 77 77: def execute_insert(sql, opts={}, &block) 78: execute_dui(sql, opts, &block) 79: end
Return a hash containing index information. Hash keys are index name symbols. Values are subhashes with two keys, :columns and :unique. The value of :columns is an array of symbols of column names. The value of :unique is true or false depending on if the index is unique.
Should not include the primary key index, functional indexes, or partial indexes.
DB.indexes(:artists) # => {:artists_name_ukey=>{:columns=>[:name], :unique=>true}}
# File lib/sequel/database/query.rb, line 99 99: def indexes(table, opts={}) 100: raise NotImplemented, "#indexes should be overridden by adapters" 101: end
Parse the schema from the database. Returns the schema for the given table as an array with all members being arrays of length 2, the first member being the column name, and the second member being a hash of column information. Available options are:
:reload : | Ignore any cached results, and get fresh information from the database. |
:schema : | An explicit schema to use. It may also be implicitly provided via the table name. |
If schema parsing is supported by the database, the column information should at least contain the following columns:
:allow_null : | Whether NULL is an allowed value for the column. |
:db_type : | The database type for the column, as a database specific string. |
:default : | The database default for the column, as a database specific string. |
:primary_key : | Whether the columns is a primary key column. If this column is not present, it means that primary key information is unavailable, not that the column is not a primary key. |
:ruby_default : | The database default for the column, as a ruby object. In many cases, complex database defaults cannot be parsed into ruby objects. |
:type : | A symbol specifying the type, such as :integer or :string. |
Example:
DB.schema(:artists) # [[:id, # {:type=>:integer, # :primary_key=>true, # :default=>"nextval('artist_id_seq'::regclass)", # :ruby_default=>nil, # :db_type=>"integer", # :allow_null=>false}], # [:name, # {:type=>:string, # :primary_key=>false, # :default=>nil, # :ruby_default=>nil, # :db_type=>"text", # :allow_null=>false}]]
# File lib/sequel/database/query.rb, line 152 152: def schema(table, opts={}) 153: raise(Error, 'schema parsing is not implemented on this database') unless respond_to?(:schema_parse_table, true) 154: 155: sch, table_name = schema_and_table(table) 156: quoted_name = quote_schema_table(table) 157: opts = opts.merge(:schema=>sch) if sch && !opts.include?(:schema) 158: 159: @schemas.delete(quoted_name) if opts[:reload] 160: return @schemas[quoted_name] if @schemas[quoted_name] 161: 162: cols = schema_parse_table(table_name, opts) 163: raise(Error, 'schema parsing returned no columns, table probably doesn\'t exist') if cols.nil? || cols.empty? 164: cols.each{|_,c| c[:ruby_default] = column_schema_to_ruby_default(c[:default], c[:type])} 165: @schemas[quoted_name] = cols 166: end
Starts a database transaction. When a database transaction is used, either all statements are successful or none of the statements are successful. Note that MySQL MyISAM tabels do not support transactions.
The following options are respected:
:isolation : | The transaction isolation level to use for this transaction, should be :uncommitted, :committed, :repeatable, or :serializable, used if given and the database/adapter supports customizable transaction isolation levels. |
:prepare : | A string to use as the transaction identifier for a prepared transaction (two-phase commit), if the database/adapter supports prepared transactions. |
:server : | The server to use for the transaction. |
:savepoint : | Whether to create a new savepoint for this transaction, only respected if the database/adapter supports savepoints. By default Sequel will reuse an existing transaction, so if you want to use a savepoint you must use this option. |
# File lib/sequel/database/query.rb, line 206 206: def transaction(opts={}, &block) 207: synchronize(opts[:server]) do |conn| 208: return yield(conn) if already_in_transaction?(conn, opts) 209: _transaction(conn, opts, &block) 210: end 211: end
These methods execute code on the database that modifies the database‘s schema.