Class Sequel::Database
In: lib/sequel/adapters/do.rb
lib/sequel/adapters/jdbc.rb
lib/sequel/adapters/swift.rb
lib/sequel/database.rb
lib/sequel/database/schema_methods.rb
lib/sequel/database/connecting.rb
lib/sequel/database/dataset.rb
lib/sequel/database/dataset_defaults.rb
lib/sequel/database/logging.rb
lib/sequel/database/misc.rb
lib/sequel/database/query.rb
lib/sequel/extensions/query.rb
lib/sequel/extensions/schema_dumper.rb
Parent: Sequel::Database

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.

Methods

<<   []   adapter_class   adapter_scheme   adapter_scheme   add_column   add_index   add_servers   alter_table   call   call_sproc   cast_type_literal   connect   connect   connect   connect   connect   create_or_replace_view   create_table   create_table!   create_table?   create_view   database_type   dataset   dataset   dataset   dataset   disconnect   drop_column   drop_index   drop_table   drop_view   dump_indexes_migration   dump_schema_migration   dump_table_schema   each_server   execute   execute   execute   execute   execute_ddl   execute_ddl   execute_dui   execute_dui   execute_dui   execute_dui   execute_insert   execute_insert   execute_insert   execute_insert   fetch   from   get   identifier_input_method   identifier_input_method   identifier_input_method=   identifier_input_method=   identifier_output_method   identifier_output_method   identifier_output_method=   identifier_output_method=   indexes   indexes   inspect   jndi?   literal   log_info   log_yield   logger=   new   new   new   new   query   quote_identifiers=   quote_identifiers=   quote_identifiers?   remove_servers   rename_column   rename_table   run   schema   select   serial_primary_key_options   servers   set_column_default   set_column_type   single_threaded=   single_threaded?   subadapter   supports_prepared_transactions?   supports_savepoints?   supports_transaction_isolation_levels?   synchronize   table_exists?   tables   tables   test_connection   transaction   typecast_value   uri   uri   uri   url  

Included Modules

Attributes

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.

Public Class methods

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.

[Source]

    # 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

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.

[Source]

    # 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 JDBC requires one.

[Source]

     # 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

Public Instance methods

Execute the given stored procedure with the give name. If a block is given, the stored procedure should return rows.

[Source]

     # 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

Setup a DataObjects::Connection to the database.

[Source]

    # 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.

[Source]

    # 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 using JavaSQL::DriverManager.getConnection.

[Source]

     # 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:             driver.new.connect(args[0], props) rescue (raise e)
172:           end
173:         end
174:         setup_connection(conn)
175:       end

Return a Sequel::Swift::Dataset object for this database.

[Source]

    # 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.

[Source]

    # File lib/sequel/adapters/do.rb, line 59
59:       def dataset(opts = nil)
60:         DataObjects::Dataset.new(self, opts)
61:       end

Return instances of JDBC::Dataset with the given opts.

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 178
178:       def dataset(opts = nil)
179:         JDBC::Dataset.new(self, opts)
180:       end

Execute the given SQL, yielding a Swift::Result if a block is given.

[Source]

    # 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.

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 184
184:       def execute(sql, opts={}, &block)
185:         return call_sproc(sql, opts, &block) if opts[:sproc]
186:         return execute_prepared_statement(sql, opts, &block) if [Symbol, Dataset].any?{|c| sql.is_a?(c)}
187:         synchronize(opts[:server]) do |conn|
188:           statement(conn) do |stmt|
189:             if block_given?
190:               yield log_yield(sql){stmt.executeQuery(sql)}
191:             else
192:               case opts[:type]
193:               when :ddl
194:                 log_yield(sql){stmt.execute(sql)}
195:               when :insert
196:                 log_yield(sql) do
197:                   if requires_return_generated_keys?
198:                     stmt.executeUpdate(sql, JavaSQL::Statement.RETURN_GENERATED_KEYS)
199:                   else
200:                     stmt.executeUpdate(sql)
201:                   end
202:                 end
203:                 last_insert_id(conn, opts.merge(:stmt=>stmt))
204:               else
205:                 log_yield(sql){stmt.executeUpdate(sql)}
206:               end
207:             end
208:           end
209:         end
210:       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.

[Source]

    # 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

Execute the given DDL SQL, which should not return any values or rows.

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 215
215:       def execute_ddl(sql, opts={})
216:         execute(sql, {:type=>:ddl}.merge(opts))
217:       end

Execute the SQL on the this database, returning the number of affected rows.

[Source]

    # 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
execute_dui(sql, opts={})

Alias for execute

Execute the SQL on the this database, returning the number of affected rows.

[Source]

    # File lib/sequel/adapters/do.rb, line 92
92:       def execute_dui(sql, opts={})
93:         execute(sql, opts)
94:       end

Execute the given INSERT SQL, returning the last inserted row id.

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 221
221:       def execute_insert(sql, opts={})
222:         execute(sql, {:type=>:insert}.merge(opts))
223:       end

Execute the SQL on this database, returning the primary key of the table being inserted to.

[Source]

     # File lib/sequel/adapters/do.rb, line 98
 98:       def execute_insert(sql, opts={})
 99:         execute(sql, opts.merge(:type=>:insert))
100:       end

Execute the SQL on this database, returning the primary key of the table being inserted to.

[Source]

     # 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.

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 226
226:       def indexes(table, opts={})
227:         m = output_identifier_meth
228:         im = input_identifier_meth
229:         schema, table = schema_and_table(table)
230:         schema ||= opts[:schema]
231:         schema = im.call(schema) if schema
232:         table = im.call(table)
233:         indexes = {}
234:         metadata(:getIndexInfo, nil, schema, table, false, true) do |r|
235:           next unless name = r[:column_name]
236:           next if respond_to?(:primary_key_index_re, true) and r[:index_name] =~ primary_key_index_re 
237:           i = indexes[m.call(r[:index_name])] ||= {:columns=>[], :unique=>[false, 0].include?(r[:non_unique])}
238:           i[:columns] << m.call(name)
239:         end
240:         indexes
241:       end

Whether or not JNDI is being used for this connection.

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 262
262:       def jndi?
263:         !!(uri =~ JNDI_URI_REGEXP)
264:       end

Return the subadapter type for this database, i.e. sqlite3 for do:sqlite3::memory:.

[Source]

     # File lib/sequel/adapters/do.rb, line 104
104:       def subadapter
105:         uri.split(":").first
106:       end

All tables in this database

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 244
244:       def tables(opts={})
245:         ts = []
246:         m = output_identifier_meth
247:         metadata(:getTables, nil, nil, nil, ['TABLE'].to_java(:string)){|h| ts << m.call(h[:table_name])}
248:         ts
249:       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.

[Source]

     # File lib/sequel/adapters/jdbc.rb, line 255
255:       def uri(opts={})
256:         opts = @opts.merge(opts)
257:         ur = opts[:uri] || opts[:url] || opts[:database]
258:         ur =~ /^\Ajdbc:/ ? ur : "jdbc:#{ur}"
259:       end

Return the DataObjects URI for the Sequel URI, removing the do: prefix.

[Source]

     # 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

Methods that modify the database schema

These methods execute code on the database that modifies the database‘s schema.

Constants

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

Public Instance methods

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.

[Source]

    # 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:

  • :ignore_errors - Ignore any DatabaseErrors that are raised

See alter_table.

[Source]

    # 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.

[Source]

    # 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'))

[Source]

     # 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.

[Source]

    # 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)

[Source]

     # 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

[Source]

     # 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'))

[Source]

     # 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.

[Source]

     # 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.

[Source]

     # 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 tables corresponding to the given names:

  DB.drop_table(:posts, :comments)

[Source]

     # File lib/sequel/database/schema_methods.rb, line 156
156:     def drop_table(*names)
157:       names.each do |n|
158:         execute_ddl(drop_table_sql(n))
159:         remove_cached_schema(n)
160:       end
161:       nil
162:     end

Drops one or more views corresponding to the given names:

  DB.drop_view(:cheap_items)

[Source]

     # 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.

[Source]

     # 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]

[Source]

     # 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.

[Source]

     # 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.

[Source]

     # 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

Methods relating to adapters, connecting, disconnecting, and sharding

This methods involve the Database‘s connection pool.

Constants

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

Attributes

pool  [R]  The connection pool for this Database instance. All Database instances have their own connection pools.

Public Class methods

The Database subclass for the given adapter scheme. Raises Sequel::AdapterNotFound if the adapter could not be loaded.

[Source]

    # 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

Returns the scheme symbol for the Database class.

[Source]

    # File lib/sequel/database/connecting.rb, line 39
39:     def self.adapter_scheme
40:       @scheme
41:     end

Connects to a database. See Sequel.connect.

[Source]

    # 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

Sets the default single_threaded mode for new databases. See Sequel.single_threaded=.

[Source]

    # File lib/sequel/database/connecting.rb, line 88
88:     def self.single_threaded=(value)
89:       @@single_threaded = value
90:     end

Public Instance methods

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

[Source]

     # 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"})

[Source]

     # 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.

[Source]

     # 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

[Source]

     # 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

[Source]

     # 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}}

[Source]

     # 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)

[Source]

     # 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

An array of servers/shards for this Database object.

  DB.servers # Unsharded: => [:default]
  DB.servers # Sharded:   => [:default, :server1, :server2]

[Source]

     # File lib/sequel/database/connecting.rb, line 203
203:     def servers
204:       pool.servers
205:     end

Returns true if the database is using a single-threaded connection pool.

[Source]

     # 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

[Source]

     # 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.

[Source]

     # File lib/sequel/database/connecting.rb, line 233
233:     def test_connection(server=nil)
234:       synchronize(server){|conn|}
235:       true
236:     end

Methods that create datasets

These methods all return instances of this database‘s dataset class.

Public Instance methods

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"

[Source]

    # File lib/sequel/database/dataset.rb, line 19
19:     def [](*args)
20:       (String === args.first) ? fetch(*args) : from(*args)
21:     end

Returns a blank dataset for this database.

  DB.dataset # SELECT *
  DB.dataset.from(:items) # SELECT * FROM items

[Source]

    # File lib/sequel/database/dataset.rb, line 27
27:     def dataset
28:       ds = Sequel::Dataset.new(self)
29:     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

[Source]

    # 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)

[Source]

    # 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

[Source]

    # File lib/sequel/database/dataset.rb, line 65
65:     def select(*args, &block)
66:       dataset.select(*args, &block)
67:     end

Methods that set defaults for created datasets

This methods change the default behavior of this database‘s datasets.

Attributes

default_schema  [RW]  The default schema to use, generally should be nil.

Public Class methods

The method to call on identifiers going into the database

[Source]

    # File lib/sequel/database/dataset_defaults.rb, line 18
18:     def self.identifier_input_method
19:       @@identifier_input_method
20:     end

Set the method to call on identifiers going into the database See Sequel.identifier_input_method=.

[Source]

    # File lib/sequel/database/dataset_defaults.rb, line 24
24:     def self.identifier_input_method=(v)
25:       @@identifier_input_method = v || ""
26:     end

The method to call on identifiers coming from the database

[Source]

    # File lib/sequel/database/dataset_defaults.rb, line 29
29:     def self.identifier_output_method
30:       @@identifier_output_method
31:     end

Set the method to call on identifiers coming from the database See Sequel.identifier_output_method=.

[Source]

    # File lib/sequel/database/dataset_defaults.rb, line 35
35:     def self.identifier_output_method=(v)
36:       @@identifier_output_method = v || ""
37:     end

Sets the default quote_identifiers mode for new databases. See Sequel.quote_identifiers=.

[Source]

    # File lib/sequel/database/dataset_defaults.rb, line 41
41:     def self.quote_identifiers=(value)
42:       @@quote_identifiers = value
43:     end

Public Instance methods

The method to call on identifiers going into the database

[Source]

    # 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

[Source]

    # 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

[Source]

    # 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'}

[Source]

    # 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"

[Source]

     # 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.

[Source]

     # 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

Methods relating to logging

This methods affect relating to the logging of executed SQL.

Attributes

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.

Public Instance methods

Log a message at level info to all loggers.

[Source]

    # 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.

[Source]

    # 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

Remove any existing loggers and just use the given logger:

  DB.logger = Logger.new($stdout)

[Source]

    # File lib/sequel/database/logging.rb, line 44
44:     def logger=(logger)
45:       @loggers = Array(logger)
46:     end

Miscellaneous methods

These methods don‘t fit neatly into another category.

Attributes

opts  [R]  The options hash for this database

Public Class methods

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.

[Source]

    # 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

Public Instance methods

Cast the given type to a literal type

  DB.cast_type_literal(Float) # double precision
  DB.cast_type_literal(:foo) # foo

[Source]

    # File lib/sequel/database/misc.rb, line 67
67:     def cast_type_literal(type)
68:       type_literal(:type=>type)
69:     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).

[Source]

    # File lib/sequel/database/misc.rb, line 74
74:     def inspect
75:       "#<#{self.class}: #{(uri rescue opts).inspect}>" 
76:     end

Proxy the literal call to the dataset.

  DB.literal(1) # 1
  DB.literal(:a) # a
  DB.literal('a') # 'a'

[Source]

    # File lib/sequel/database/misc.rb, line 83
83:     def literal(v)
84:       schema_utility_dataset.literal(v)
85:     end

Default serial primary key options, used by the table creation code.

[Source]

    # 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.

[Source]

    # 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.

[Source]

     # 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.

[Source]

     # 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.

[Source]

     # 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"

[Source]

     # 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

Explicit alias of uri for easier subclassing.

[Source]

     # File lib/sequel/database/misc.rb, line 150
150:     def url
151:       uri
152:     end

Methods that execute queries and/or return results

This methods generally execute SQL code on the database server.

Constants

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/

Attributes

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.

Public Instance methods

Runs the supplied SQL statement string on the database server. Alias for run.

[Source]

    # File lib/sequel/database/query.rb, line 41
41:     def <<(sql)
42:       run(sql)
43:     end

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

[Source]

    # 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:

  • :same_db - Create a dump for the same database type, so don‘t ignore errors if the index statements fail.

[Source]

    # 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:

  • :same_db - Don‘t attempt to translate database types to ruby types. If this isn‘t set to true, all database types will be translated to ruby types, but there is no guarantee that the migration generated will yield the same type. Without this set, types that aren‘t recognized will be translated to a string-like type.
  • :indexes - If set to false, don‘t dump indexes (they can be added later via dump_index_migration).

[Source]

    # 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.

[Source]

    # 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.

[Source]

    # 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.

[Source]

    # 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 DELETE, UPDATE, or INSERT statement. By default, calls execute. This method should not be called directly by user code.

[Source]

    # File lib/sequel/database/query.rb, line 70
70:     def execute_dui(sql, opts={}, &block)
71:       execute(sql, opts, &block)
72:     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.

[Source]

    # File lib/sequel/database/query.rb, line 77
77:     def execute_insert(sql, opts={}, &block)
78:       execute_dui(sql, opts, &block)
79:     end

Returns a single value from the database, e.g.:

  DB.get(1) # SELECT 1
  # => 1
  DB.get{version{}} # SELECT server_version()

[Source]

    # File lib/sequel/database/query.rb, line 86
86:     def get(*args, &block)
87:       dataset.get(*args, &block)
88:     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}}

[Source]

     # File lib/sequel/database/query.rb, line 99
 99:     def indexes(table, opts={})
100:       raise NotImplemented, "#indexes should be overridden by adapters"
101:     end

Return a dataset modified by the query block

[Source]

    # File lib/sequel/extensions/query.rb, line 8
 8:     def query(&block)
 9:       dataset.query(&block)
10:     end

Runs the supplied SQL statement string on the database server. Returns nil. Options:

:server :The server to run the SQL on.
  DB.run("SET some_server_variable = 42")

[Source]

     # File lib/sequel/database/query.rb, line 108
108:     def run(sql, opts={})
109:       execute_ddl(sql, opts)
110:       nil
111:     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}]]

[Source]

     # 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

Returns true if a table with the given name exists. This requires a query to the database.

  DB.table_exists?(:foo) # => false

[Source]

     # File lib/sequel/database/query.rb, line 172
172:     def table_exists?(name)
173:       begin 
174:         from(name).first
175:         true
176:       rescue
177:         false
178:       end
179:     end

Return all tables in the database as an array of symbols.

  DB.tables # => [:albums, :artists]

[Source]

     # File lib/sequel/database/query.rb, line 184
184:     def tables(opts={})
185:       raise NotImplemented, "#tables should be overridden by adapters"
186:     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.

[Source]

     # 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