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
Public Class
- adapter_class
- adapter_scheme
- after_initialize
- connect
- extension
- load_adapter
- new
- register_extension
- run_after_initialize
- set_shared_adapter_scheme
Public Instance
- <<
- []
- adapter_scheme
- add_column
- add_index
- add_servers
- after_commit
- after_rollback
- alter_table
- alter_table_generator
- cache_schema
- call
- cast_type_literal
- check_string_typecast_bytesize
- create_join_table
- create_join_table!
- create_join_table?
- create_or_replace_view
- create_table
- create_table!
- create_table?
- create_table_generator
- create_view
- database_type
- dataset
- dataset_class
- dataset_class=
- default_string_column_size
- disconnect
- disconnect_connection
- drop_column
- drop_index
- drop_join_table
- drop_table
- drop_table?
- drop_view
- execute_ddl
- execute_dui
- execute_insert
- extend_datasets
- extension
- fetch
- freeze
- from
- from_application_timestamp
- get
- global_index_namespace?
- in_transaction?
- inspect
- literal
- literal_symbol
- literal_symbol_set
- log_connection_info
- log_connection_yield
- log_exception
- log_info
- log_warn_duration
- logger=
- loggers
- new_connection
- opts
- pool
- prepared_statement
- prepared_statements
- quote_identifier
- remove_servers
- rename_column
- rename_table
- rollback_checker
- rollback_on_exit
- run
- schema
- schema_type_class
- select
- serial_primary_key_options
- servers
- set_column_default
- set_column_type
- set_prepared_statement
- sharded?
- single_threaded?
- sql_log_level
- supports_create_table_if_not_exists?
- supports_deferrable_constraints?
- supports_deferrable_foreign_key_constraints?
- supports_drop_table_if_exists?
- supports_foreign_key_parsing?
- supports_index_parsing?
- supports_partial_indexes?
- supports_prepared_transactions?
- supports_savepoints?
- supports_savepoints_in_prepared_transactions?
- supports_schema_parsing?
- supports_table_listing?
- supports_transaction_isolation_levels?
- supports_transactional_ddl?
- supports_view_listing?
- supports_views_with_check_option?
- supports_views_with_local_check_option?
- synchronize
- table_exists?
- test_connection
- timezone
- timezone
- to_application_timestamp
- transaction
- transaction_isolation_level
- typecast_value
- uri
- url
- valid_connection?
Contents
- 1 - Methods that execute queries and/or return results
- 2 - Methods that modify the database schema
- 3 - Methods that create datasets
- 4 - Methods relating to adapters, connecting, disconnecting, and sharding
- 5 - Methods that set defaults for created datasets
- 6 - Methods relating to logging
- 7 - Miscellaneous methods
- 8 - Methods related to database transactions
- 9 - Methods that describe what the database supports
Constants
OPTS | = | Sequel::OPTS |
1 - Methods that execute queries and/or return results
Constants
COLUMN_SCHEMA_DATETIME_TYPES | = | [:date, :datetime].freeze | ||
COLUMN_SCHEMA_STRING_TYPES | = | [:string, :blob, :date, :datetime, :time, :enum, :set, :interval].freeze | ||
INTEGER1_MIN_MAX | = | [-128, 127].freeze | ||
INTEGER2_MIN_MAX | = | [-32768, 32767].freeze | ||
INTEGER3_MIN_MAX | = | [-8388608, 8388607].freeze | ||
INTEGER4_MIN_MAX | = | [-2147483648, 2147483647].freeze | ||
INTEGER8_MIN_MAX | = | [-9223372036854775808, 9223372036854775807].freeze | ||
UNSIGNED_INTEGER1_MIN_MAX | = | [0, 255].freeze | ||
UNSIGNED_INTEGER2_MIN_MAX | = | [0, 65535].freeze | ||
UNSIGNED_INTEGER3_MIN_MAX | = | [0, 16777215].freeze | ||
UNSIGNED_INTEGER4_MIN_MAX | = | [0, 4294967295].freeze | ||
UNSIGNED_INTEGER8_MIN_MAX | = | [0, 18446744073709551615].freeze |
Attributes
cache_schema | [RW] |
Whether the schema should be cached for this database. True by default for performance, can be set to false to always issue a database query to get the schema. |
prepared_statements | [R] |
The prepared statement object hash for this database, keyed by name symbol |
Public Instance methods
Runs the supplied SQL
statement string on the database server. Returns self so it can be safely chained:
DB << "UPDATE albums SET artist_id = NULL" << "DROP TABLE artists"
# File lib/sequel/database/query.rb 25 def <<(sql) 26 run(sql) 27 self 28 end
Call the prepared statement with the given name with the given hash of arguments.
DB[:items].where(id: 1).prepare(:first, :sa) DB.call(:sa) # SELECT * FROM items WHERE id = 1
# File lib/sequel/database/query.rb 35 def call(ps_name, hash=OPTS, &block) 36 prepared_statement(ps_name).call(hash, &block) 37 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 42 def execute_ddl(sql, opts=OPTS, &block) 43 execute_dui(sql, opts, &block) 44 end
Method that should be used when issuing a DELETE or UPDATE statement. By default, calls execute. This method should not be called directly by user code.
# File lib/sequel/database/query.rb 49 def execute_dui(sql, opts=OPTS, &block) 50 execute(sql, opts, &block) 51 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 56 def execute_insert(sql, opts=OPTS, &block) 57 execute_dui(sql, opts, &block) 58 end
Returns a single value from the database, see Dataset#get
.
DB.get(1) # SELECT 1 # => 1 DB.get{server_version.function} # SELECT server_version()
# File lib/sequel/database/query.rb 65 def get(*args, &block) 66 @default_dataset.get(*args, &block) 67 end
Runs the supplied SQL
statement string on the database server. Returns nil. Options:
:server |
The server to run the |
DB.run("SET some_server_variable = 42")
# File lib/sequel/database/query.rb 74 def run(sql, opts=OPTS) 75 sql = literal(sql) if sql.is_a?(SQL::PlaceholderLiteralString) 76 execute_ddl(sql, opts) 77 nil 78 end
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. The table argument can also be a dataset, as long as it only has one table. 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 hash should contain at least the following entries:
: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, or nil if there is no default value. |
: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, in which case nil will be used as the value. |
: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 121 def schema(table, opts=OPTS) 122 raise(Error, 'schema parsing is not implemented on this database') unless supports_schema_parsing? 123 124 opts = opts.dup 125 tab = if table.is_a?(Dataset) 126 o = table.opts 127 from = o[:from] 128 raise(Error, "can only parse the schema for a dataset with a single from table") unless from && from.length == 1 && !o.include?(:join) && !o.include?(:sql) 129 table.first_source_table 130 else 131 table 132 end 133 134 qualifiers = split_qualifiers(tab) 135 table_name = qualifiers.pop 136 sch = qualifiers.pop 137 information_schema_schema = case qualifiers.length 138 when 1 139 Sequel.identifier(*qualifiers) 140 when 2 141 Sequel.qualify(*qualifiers) 142 end 143 144 if table.is_a?(Dataset) 145 quoted_name = table.literal(tab) 146 opts[:dataset] = table 147 else 148 quoted_name = schema_utility_dataset.literal(table) 149 end 150 151 opts[:schema] = sch if sch && !opts.include?(:schema) 152 opts[:information_schema_schema] = information_schema_schema if information_schema_schema && !opts.include?(:information_schema_schema) 153 154 Sequel.synchronize{@schemas.delete(quoted_name)} if opts[:reload] 155 if v = Sequel.synchronize{@schemas[quoted_name]} 156 return v 157 end 158 159 cols = schema_parse_table(table_name, opts) 160 raise(Error, "schema parsing returned no columns, table #{table_name.inspect} probably doesn't exist") if cols.nil? || cols.empty? 161 162 primary_keys = 0 163 auto_increment_set = false 164 cols.each do |_,c| 165 auto_increment_set = true if c.has_key?(:auto_increment) 166 primary_keys += 1 if c[:primary_key] 167 end 168 169 cols.each do |_,c| 170 c[:ruby_default] = column_schema_to_ruby_default(c[:default], c[:type]) unless c.has_key?(:ruby_default) 171 if c[:primary_key] && !auto_increment_set 172 # If adapter didn't set it, assume that integer primary keys are auto incrementing 173 c[:auto_increment] = primary_keys == 1 && !!(c[:db_type] =~ /int/io) 174 end 175 if !c[:max_length] && c[:type] == :string && (max_length = column_schema_max_length(c[:db_type])) 176 c[:max_length] = max_length 177 end 178 if !c[:max_value] && !c[:min_value] 179 min_max = case c[:type] 180 when :integer 181 column_schema_integer_min_max_values(c) 182 when :decimal 183 column_schema_decimal_min_max_values(c) 184 end 185 c[:min_value], c[:max_value] = min_max if min_max 186 end 187 end 188 schema_post_process(cols) 189 190 Sequel.synchronize{@schemas[quoted_name] = cols} if cache_schema 191 cols 192 end
Returns true if a table with the given name exists. This requires a query to the database.
DB.table_exists?(:foo) # => false # SELECT NULL FROM foo LIMIT 1
Note that since this does a SELECT from the table, it can give false negatives if you don’t have permission to SELECT from the table.
# File lib/sequel/database/query.rb 202 def table_exists?(name) 203 sch, table_name = schema_and_table(name) 204 name = SQL::QualifiedIdentifier.new(sch, table_name) if sch 205 ds = from(name) 206 transaction(:savepoint=>:only){_table_exists?(ds)} 207 true 208 rescue DatabaseError 209 false 210 end
2 - Methods that modify the database schema
Constants
COLUMN_DEFINITION_ORDER | = | [:collate, :default, :null, :unique, :primary_key, :auto_increment, :references].freeze |
The order of column modifiers to use when defining a column. |
|
COMBINABLE_ALTER_TABLE_OPS | = | [:add_column, :drop_column, :rename_column, :set_column_type, :set_column_default, :set_column_null, :add_constraint, :drop_constraint].freeze |
The alter table operations that are combinable. |
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, String, unique: true, null: false DB.add_column :items, :category, String, default: 'ruby'
See alter_table
.
# File lib/sequel/database/schema_methods.rb 25 def add_column(table, *args) 26 alter_table(table) {add_column(*args)} 27 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 |
:name |
Name to use for index instead of default |
See alter_table
.
# File lib/sequel/database/schema_methods.rb 40 def add_index(table, columns, options=OPTS) 41 e = options[:ignore_errors] 42 begin 43 alter_table(table){add_index(columns, options)} 44 rescue DatabaseError 45 raise unless e 46 end 47 nil 48 end
Alters the given table with the specified block. Example:
DB.alter_table :items do add_column :category, String, default: 'ruby' drop_column :category rename_column :cntr, :counter set_column_type :value, Float set_column_default :value, 4.2 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 guide.
# File lib/sequel/database/schema_methods.rb 67 def alter_table(name, &block) 68 generator = alter_table_generator(&block) 69 remove_cached_schema(name) 70 apply_alter_table_generator(name, generator) 71 nil 72 end
Return a new Schema::AlterTableGenerator
instance with the receiver as the database and the given block.
# File lib/sequel/database/schema_methods.rb 76 def alter_table_generator(&block) 77 alter_table_generator_class.new(self, &block) 78 end
Create a join table using a hash of foreign keys to referenced table names. Example:
create_join_table(cat_id: :cats, dog_id: :dogs) # CREATE TABLE cats_dogs ( # cat_id integer NOT NULL REFERENCES cats, # dog_id integer NOT NULL REFERENCES dogs, # PRIMARY KEY (cat_id, dog_id) # ) # CREATE INDEX cats_dogs_dog_id_cat_id_index ON cats_dogs(dog_id, cat_id)
The primary key and index are used so that almost all operations on the table can benefit from one of the two indexes, and the primary key ensures that entries in the table are unique, which is the typical desire for a join table.
The default table name this will create is the sorted version of the two hash values, joined by an underscore. So the following two method calls create the same table:
create_join_table(cat_id: :cats, dog_id: :dogs) # cats_dogs create_join_table(dog_id: :dogs, cat_id: :cats) # cats_dogs
You can provide column options by making the values in the hash be option hashes, so long as the option hashes have a :table entry giving the table referenced:
create_join_table(cat_id: {table: :cats, type: :Bignum}, dog_id: :dogs)
You can provide a second argument which is a table options hash:
create_join_table({cat_id: :cats, dog_id: :dogs}, temp: true)
Some table options are handled specially:
:index_options |
The options to pass to the index |
:name |
The name of the table to create |
:no_index |
Set to true not to create the second index. |
:no_primary_key |
Set to true to not create the primary key. |
# File lib/sequel/database/schema_methods.rb 119 def create_join_table(hash, options=OPTS) 120 keys = hash.keys.sort 121 create_table(join_table_name(hash, options), options) do 122 keys.each do |key| 123 v = hash[key] 124 unless v.is_a?(Hash) 125 v = {:table=>v} 126 end 127 v[:null] = false unless v.has_key?(:null) 128 foreign_key(key, v) 129 end 130 primary_key(keys) unless options[:no_primary_key] 131 index(keys.reverse, options[:index_options] || OPTS) unless options[:no_index] 132 end 133 nil 134 end
Forcibly create a join table, attempting to drop it if it already exists, then creating it.
# File lib/sequel/database/schema_methods.rb 137 def create_join_table!(hash, options=OPTS) 138 drop_table?(join_table_name(hash, options)) 139 create_join_table(hash, options) 140 end
Creates the join table unless it already exists.
# File lib/sequel/database/schema_methods.rb 143 def create_join_table?(hash, options=OPTS) 144 if supports_create_table_if_not_exists? && options[:no_index] 145 create_join_table(hash, options.merge(:if_not_exists=>true)) 146 elsif !table_exists?(join_table_name(hash, options)) 147 create_join_table(hash, options) 148 end 149 end
Creates a view, replacing a view with the same name if one already exists.
DB.create_or_replace_view(:some_items, "SELECT * FROM items WHERE price < 100") DB.create_or_replace_view(:some_items, DB[:items].where(category: 'ruby'))
For databases where replacing a view is not natively supported, support is emulated by dropping a view with the same name before creating the view.
# File lib/sequel/database/schema_methods.rb 248 def create_or_replace_view(name, source, options = OPTS) 249 if supports_create_or_replace_view? 250 options = options.merge(:replace=>true) 251 else 252 swallow_database_error{drop_view(name)} 253 end 254 255 create_view(name, source, options) 256 nil 257 end
Creates a table with the columns given in the provided block:
DB.create_table :posts do primary_key :id column :title, String String :content index :title end
General options:
:as |
Create the table using the value, which should be either a dataset or a literal |
:ignore_index_errors |
Ignore any errors when creating indexes. |
:temp |
Create the table as a temporary table. |
MySQL specific options:
:charset |
The character set to use for the table. |
:collate |
The collation to use for the table. |
:engine |
The table engine to use for the table. |
PostgreSQL specific options:
:on_commit |
Either :preserve_rows (default), :drop or :delete_rows. Should only be specified when creating a temporary table. |
:foreign |
Create a foreign table. The value should be the name of the foreign server that was specified in CREATE SERVER. |
:inherits |
Inherit from a different table. An array can be specified to inherit from multiple tables. |
:unlogged |
Create the table as an unlogged table. |
:options |
The OPTIONS clause to use for foreign tables. Should be a hash where keys are option names and values are option values. Note that option names are unquoted, so you should not use untrusted keys. |
:tablespace |
The tablespace to use for the table. |
SQLite specific options:
:strict |
Create a STRICT table, which checks that the values for the columns are the correct type (similar to all other |
See Schema::CreateTableGenerator
and the “Schema Modification” guide.
# File lib/sequel/database/schema_methods.rb 196 def create_table(name, options=OPTS, &block) 197 remove_cached_schema(name) 198 if sql = options[:as] 199 raise(Error, "can't provide both :as option and block to create_table") if block 200 create_table_as(name, sql, options) 201 else 202 generator = options[:generator] || create_table_generator(&block) 203 create_table_from_generator(name, generator, options) 204 create_table_indexes_from_generator(name, generator, options) 205 end 206 nil 207 end
Forcibly create a table, attempting to drop it if it already exists, then creating it.
DB.create_table!(:a){Integer :a} # SELECT NULL FROM a LIMIT 1 -- check existence # DROP TABLE a -- drop table if already exists # CREATE TABLE a (a integer)
# File lib/sequel/database/schema_methods.rb 215 def create_table!(name, options=OPTS, &block) 216 drop_table?(name) 217 create_table(name, options, &block) 218 end
Creates the table unless the table already exists.
DB.create_table?(:a){Integer :a} # SELECT NULL FROM a LIMIT 1 -- check existence # CREATE TABLE a (a integer) -- if it doesn't already exist
# File lib/sequel/database/schema_methods.rb 225 def create_table?(name, options=OPTS, &block) 226 options = options.dup 227 generator = options[:generator] ||= create_table_generator(&block) 228 if generator.indexes.empty? && supports_create_table_if_not_exists? 229 create_table(name, options.merge!(:if_not_exists=>true)) 230 elsif !table_exists?(name) 231 create_table(name, options) 232 end 233 end
Return a new Schema::CreateTableGenerator
instance with the receiver as the database and the given block.
# File lib/sequel/database/schema_methods.rb 237 def create_table_generator(&block) 238 create_table_generator_class.new(self, &block) 239 end
Creates a view based on a dataset or an SQL
string:
DB.create_view(:cheap_items, "SELECT * FROM items WHERE price < 100") # CREATE VIEW cheap_items AS # SELECT * FROM items WHERE price < 100 DB.create_view(:ruby_items, DB[:items].where(category: 'ruby')) # CREATE VIEW ruby_items AS # SELECT * FROM items WHERE (category = 'ruby') DB.create_view(:checked_items, DB[:items].where(:foo), check: true) # CREATE VIEW checked_items AS # SELECT * FROM items WHERE foo # WITH CHECK OPTION DB.create_view(:bar_items, DB[:items].select(:foo), columns: [:bar]) # CREATE VIEW bar_items (bar) AS # SELECT foo FROM items
Options:
:columns |
The column names to use for the view. If not given, automatically determined based on the input dataset. |
:check |
Adds a WITH CHECK OPTION clause, so that attempting to modify rows in the underlying table that would not be returned by the view is not allowed. This can be set to :local to use WITH LOCAL CHECK OPTION. |
PostgreSQL/SQLite specific option:
:temp |
Create a temporary view, automatically dropped on disconnect. |
PostgreSQL specific options:
:materialized |
Creates a materialized view, similar to a regular view, but backed by a physical table. |
:recursive |
Creates a recursive view. As columns must be specified for recursive views, you can also set them as the value of this option. Since a recursive view requires a union that isn’t in a subquery, if you are providing a |
:security_invoker |
Set the security_invoker property on the view, making the access to the view use the current user’s permissions, instead of the view owner’s permissions. |
:tablespace |
The tablespace to use for materialized views. |
# File lib/sequel/database/schema_methods.rb 302 def create_view(name, source, options = OPTS) 303 execute_ddl(create_view_sql(name, source, options)) 304 remove_cached_schema(name) 305 nil 306 end
Removes a column from the specified table:
DB.drop_column :items, :category
See alter_table
.
# File lib/sequel/database/schema_methods.rb 313 def drop_column(table, *args) 314 alter_table(table) {drop_column(*args)} 315 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 323 def drop_index(table, columns, options=OPTS) 324 alter_table(table){drop_index(columns, options)} 325 end
Drop the join table that would have been created with the same arguments to create_join_table
:
drop_join_table(cat_id: :cats, dog_id: :dogs) # DROP TABLE cats_dogs
# File lib/sequel/database/schema_methods.rb 332 def drop_join_table(hash, options=OPTS) 333 drop_table(join_table_name(hash, options), options) 334 end
Drops one or more tables corresponding to the given names:
DB.drop_table(:posts) # DROP TABLE posts DB.drop_table(:posts, :comments) DB.drop_table(:posts, :comments, cascade: true)
# File lib/sequel/database/schema_methods.rb 341 def drop_table(*names) 342 options = names.last.is_a?(Hash) ? names.pop : OPTS 343 names.each do |n| 344 execute_ddl(drop_table_sql(n, options)) 345 remove_cached_schema(n) 346 end 347 nil 348 end
Drops the table if it already exists. If it doesn’t exist, does nothing.
DB.drop_table?(:a) # SELECT NULL FROM a LIMIT 1 -- check existence # DROP TABLE a -- if it already exists
# File lib/sequel/database/schema_methods.rb 356 def drop_table?(*names) 357 options = names.last.is_a?(Hash) ? names.pop : OPTS 358 if supports_drop_table_if_exists? 359 options = options.merge(:if_exists=>true) 360 names.each do |name| 361 drop_table(name, options) 362 end 363 else 364 names.each do |name| 365 drop_table(name, options) if table_exists?(name) 366 end 367 end 368 nil 369 end
Drops one or more views corresponding to the given names:
DB.drop_view(:cheap_items) DB.drop_view(:cheap_items, :pricey_items) DB.drop_view(:cheap_items, :pricey_items, cascade: true) DB.drop_view(:cheap_items, :pricey_items, if_exists: true)
Options:
:cascade |
Also drop objects depending on this view. |
:if_exists |
Do not raise an error if the view does not exist. |
PostgreSQL specific options:
:materialized |
Drop a materialized view. |
# File lib/sequel/database/schema_methods.rb 384 def drop_view(*names) 385 options = names.last.is_a?(Hash) ? names.pop : OPTS 386 names.each do |n| 387 execute_ddl(drop_view_sql(n, options)) 388 remove_cached_schema(n) 389 end 390 nil 391 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 410 def rename_column(table, *args) 411 alter_table(table) {rename_column(*args)} 412 end
Renames a table:
DB.tables #=> [:items] DB.rename_table :items, :old_items DB.tables #=> [:old_items]
# File lib/sequel/database/schema_methods.rb 398 def rename_table(name, new_name) 399 execute_ddl(rename_table_sql(name, new_name)) 400 remove_cached_schema(name) 401 nil 402 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 419 def set_column_default(table, *args) 420 alter_table(table) {set_column_default(*args)} 421 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 428 def set_column_type(table, *args) 429 alter_table(table) {set_column_type(*args)} 430 end
3 - Methods that create datasets
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"
# File lib/sequel/database/dataset.rb 21 def [](*args) 22 args.first.is_a?(String) ? fetch(*args) : from(*args) 23 end
Returns a blank dataset for this database.
DB.dataset # SELECT * DB.dataset.from(:items) # SELECT * FROM items
# File lib/sequel/database/dataset.rb 29 def dataset 30 @dataset_class.new(self) 31 end
Returns a dataset instance for the given SQL
string:
ds = DB.fetch('SELECT * FROM items')
You can then call methods on the dataset to retrieve results:
ds.all # SELECT * FROM items # => [{:column=>value, ...}, ...]
If a block is given, it is passed to each on the resulting dataset to iterate over the records returned by the query:
DB.fetch('SELECT * FROM items'){|r| p r} # {:column=>value, ...} # ...
fetch
can also perform parameterized queries for protection against SQL
injection:
ds = DB.fetch('SELECT * FROM items WHERE name = ?', "my name") ds.all # SELECT * FROM items WHERE name = 'my name'
See caveats listed in Dataset#with_sql
regarding datasets using custom SQL
and the methods that can be called on them.
# File lib/sequel/database/dataset.rb 59 def fetch(sql, *args, &block) 60 ds = @default_dataset.with_sql(sql, *args) 61 ds.each(&block) if block 62 ds 63 end
Returns a new dataset with the from
method invoked. If a block is given, it acts as a virtual row block
DB.from(:items) # SELECT * FROM items DB.from{schema[:table]} # SELECT * FROM schema.table
# File lib/sequel/database/dataset.rb 70 def from(*args, &block) 71 if block 72 @default_dataset.from(*args, &block) 73 elsif args.length == 1 && (table = args[0]).is_a?(Symbol) 74 @default_dataset.send(:cached_dataset, :"_from_#{table}_ds"){@default_dataset.from(table)} 75 else 76 @default_dataset.from(*args) 77 end 78 end
Returns a new dataset with the select method invoked.
DB.select(1) # SELECT 1 DB.select{server_version.function} # SELECT server_version() DB.select(:id).from(:items) # SELECT id FROM items
# File lib/sequel/database/dataset.rb 85 def select(*args, &block) 86 @default_dataset.select(*args, &block) 87 end
4 - Methods relating to adapters, connecting, disconnecting, and sharding
Constants
ADAPTERS | = | %w'ado amalgalite ibmdb jdbc mock mysql mysql2 odbc oracle postgres sqlanywhere sqlite tinytds trilogy'.map(&:to_sym) |
Array of supported database adapters |
Attributes
Public Class methods
The Database
subclass for the given adapter scheme. Raises Sequel::AdapterNotFound if the adapter could not be loaded.
# File lib/sequel/database/connecting.rb 16 def self.adapter_class(scheme) 17 scheme.is_a?(Class) ? scheme : load_adapter(scheme.to_sym) 18 end
Returns the scheme symbol for the Database
class.
# File lib/sequel/database/connecting.rb 21 def self.adapter_scheme 22 @scheme 23 end
Connects to a database. See Sequel.connect.
# File lib/sequel/database/connecting.rb 26 def self.connect(conn_string, opts = OPTS) 27 case conn_string 28 when String 29 if conn_string.start_with?('jdbc:') 30 c = adapter_class(:jdbc) 31 opts = opts.merge(:orig_opts=>opts.dup) 32 opts = {:uri=>conn_string}.merge!(opts) 33 else 34 uri = URI.parse(conn_string) 35 scheme = uri.scheme 36 c = adapter_class(scheme) 37 uri_options = c.send(:uri_to_options, uri) 38 uri.query.split('&').map{|s| s.split('=')}.each{|k,v| uri_options[k.to_sym] = v if k && !k.empty?} unless uri.query.to_s.strip.empty? 39 uri_options.to_a.each{|k,v| uri_options[k] = URI::DEFAULT_PARSER.unescape(v) if v.is_a?(String)} 40 opts = uri_options.merge(opts).merge!(:orig_opts=>opts.dup, :uri=>conn_string, :adapter=>scheme) 41 end 42 when Hash 43 opts = conn_string.merge(opts) 44 opts = opts.merge(:orig_opts=>opts.dup) 45 c = adapter_class(opts[:adapter_class] || opts[:adapter] || opts['adapter']) 46 else 47 raise Error, "Sequel::Database.connect takes either a Hash or a String, given: #{conn_string.inspect}" 48 end 49 50 opts = opts.inject({}) do |m, (k,v)| 51 k = :user if k.to_s == 'username' 52 m[k.to_sym] = v 53 m 54 end 55 56 begin 57 db = c.new(opts) 58 if defined?(yield) 59 return yield(db) 60 end 61 ensure 62 if defined?(yield) 63 db.disconnect if db 64 Sequel.synchronize{::Sequel::DATABASES.delete(db)} 65 end 66 end 67 db 68 end
Load the adapter from the file system. Raises Sequel::AdapterNotFound if the adapter cannot be loaded, or if the adapter isn’t registered correctly after being loaded. Options:
:map |
The Hash in which to look for an already loaded adapter (defaults to ADAPTER_MAP). |
:subdir |
The subdirectory of sequel/adapters to look in, only to be used for loading subadapters. |
# File lib/sequel/database/connecting.rb 76 def self.load_adapter(scheme, opts=OPTS) 77 map = opts[:map] || ADAPTER_MAP 78 if subdir = opts[:subdir] 79 file = "#{subdir}/#{scheme}" 80 else 81 file = scheme 82 end 83 84 unless obj = Sequel.synchronize{map[scheme]} 85 # attempt to load the adapter file 86 begin 87 require "sequel/adapters/#{file}" 88 rescue LoadError => e 89 # If subadapter file doesn't exist, just return, 90 # using the main adapter class without database customizations. 91 return if subdir 92 raise Sequel.convert_exception_class(e, AdapterNotFound) 93 end 94 95 # make sure we actually loaded the adapter 96 unless obj = Sequel.synchronize{map[scheme]} 97 raise AdapterNotFound, "Could not load #{file} adapter: adapter class not registered in ADAPTER_MAP" 98 end 99 end 100 101 obj 102 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
# File lib/sequel/database/connecting.rb 161 def adapter_scheme 162 self.class.adapter_scheme 163 end
Dynamically add new servers or modify server options at runtime. Also adds new servers to the connection pool. Only usable when using a sharded connection pool.
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 173 def add_servers(servers) 174 unless sharded? 175 raise Error, "cannot call Database#add_servers on a Database instance that does not use a sharded connection pool" 176 end 177 178 h = @opts[:servers] 179 Sequel.synchronize{h.merge!(servers)} 180 @pool.add_servers(servers.keys) 181 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.
Sequel.connect('jdbc:postgres://...').database_type # => :postgres
# File lib/sequel/database/connecting.rb 192 def database_type 193 adapter_scheme 194 end
Disconnects all available connections from the connection pool. Any connections currently in use will not be disconnected. Options:
:server |
Should be a symbol specifing the server to disconnect from, or an array of symbols to specify multiple servers. |
Example:
DB.disconnect # All servers DB.disconnect(server: :server1) # Single server DB.disconnect(server: [:server1, :server2]) # Multiple servers
# File lib/sequel/database/connecting.rb 206 def disconnect(opts = OPTS) 207 pool.disconnect(opts) 208 end
Should only be called by the connection pool code to disconnect a connection. By default, calls the close method on the connection object, since most adapters use that, but should be overwritten on other adapters.
# File lib/sequel/database/connecting.rb 213 def disconnect_connection(conn) 214 conn.close 215 end
Connect to the given server/shard. Handles database-generic post-connection setup not handled by connect, using the :after_connect and :connect_sqls options.
# File lib/sequel/database/connecting.rb 247 def new_connection(server) 248 conn = connect(server) 249 opts = server_opts(server) 250 251 if ac = opts[:after_connect] 252 if ac.arity == 2 253 ac.call(conn, server) 254 else 255 ac.call(conn) 256 end 257 end 258 259 if cs = opts[:connect_sqls] 260 cs.each do |sql| 261 log_connection_execute(conn, sql) 262 end 263 end 264 265 conn 266 end
Dynamically remove existing servers from the connection pool. Only usable when using a sharded connection pool
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 226 def remove_servers(*servers) 227 unless sharded? 228 raise Error, "cannot call Database#remove_servers on a Database instance that does not use a sharded connection pool" 229 end 230 231 h = @opts[:servers] 232 servers.flatten.each{|s| Sequel.synchronize{h.delete(s)}} 233 @pool.remove_servers(servers) 234 end
An array of servers/shards for this Database
object.
DB.servers # Unsharded: => [:default] DB.servers # Sharded: => [:default, :server1, :server2]
# File lib/sequel/database/connecting.rb 240 def servers 241 pool.servers 242 end
Returns true if the database is using a single-threaded connection pool.
# File lib/sequel/database/connecting.rb 269 def single_threaded? 270 @single_threaded 271 end
:nocov:
# File lib/sequel/database/connecting.rb 275 def synchronize(server=nil) 276 @pool.hold(server || :default){|conn| yield conn} 277 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 301 def test_connection(server=nil) 302 synchronize(server){|conn|} 303 true 304 end
Check whether the given connection is currently valid, by running a query against it. If the query fails, the connection should probably be removed from the connection pool.
# File lib/sequel/database/connecting.rb 310 def valid_connection?(conn) 311 sql = valid_connection_sql 312 begin 313 log_connection_execute(conn, sql) 314 rescue Sequel::DatabaseError, *database_error_classes 315 false 316 else 317 true 318 end 319 end
5 - Methods that set defaults for created datasets
Attributes
dataset_class | [R] |
The class to use for creating datasets. Should respond to new with the |
Public Instance methods
If the database has any dataset modules associated with it, use a subclass of the given class that includes the modules as the dataset class.
# File lib/sequel/database/dataset_defaults.rb 18 def dataset_class=(c) 19 unless @dataset_modules.empty? 20 c = Class.new(c) 21 @dataset_modules.each{|m| c.send(:include, m)} 22 end 23 @dataset_class = c 24 reset_default_dataset 25 end
Equivalent to extending all datasets produced by the database with a module. What it actually does is use a subclass of the current dataset_class
as the new dataset_class
, and include the module in the subclass. Instead of a module, you can provide a block that is used to create an anonymous module.
This allows you to override any of the dataset methods even if they are defined directly on the dataset class that this Database
object uses.
If a block is given, a Dataset::DatasetModule
instance is created, allowing for the easy creation of named dataset methods that will do caching.
Examples:
# Introspect columns for all of DB's datasets DB.extend_datasets(Sequel::ColumnsIntrospection) # Trace all SELECT queries by printing the SQL and the full backtrace DB.extend_datasets do def fetch_rows(sql) puts sql puts caller super end end # Add some named dataset methods DB.extend_datasets do order :by_id, :id select :with_id_and_name, :id, :name where :active, :active end DB[:table].active.with_id_and_name.by_id # SELECT id, name FROM table WHERE active ORDER BY id
# File lib/sequel/database/dataset_defaults.rb 62 def extend_datasets(mod=nil, &block) 63 raise(Error, "must provide either mod or block, not both") if mod && block 64 mod = Dataset::DatasetModule.new(&block) if block 65 if @dataset_modules.empty? 66 @dataset_modules = [mod] 67 @dataset_class = Class.new(@dataset_class) 68 else 69 @dataset_modules << mod 70 end 71 @dataset_class.send(:include, mod) 72 reset_default_dataset 73 end
6 - Methods relating to logging
Attributes
log_connection_info | [RW] |
Whether to include information about the connection in use when logging queries. |
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_log_level | [RW] |
Log level at which to log |
Public Instance methods
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 37 def log_connection_yield(sql, conn, args=nil) 38 return yield if skip_logging? 39 sql = "#{connection_info(conn) if conn && log_connection_info}#{sql}#{"; #{args.inspect}" if args}" 40 timer = Sequel.start_timer 41 42 begin 43 yield 44 rescue => e 45 log_exception(e, sql) 46 raise 47 ensure 48 log_duration(Sequel.elapsed_seconds_since(timer), sql) unless e 49 end 50 end
Log a message at error level, with information about the exception.
# File lib/sequel/database/logging.rb 26 def log_exception(exception, message) 27 log_each(:error, "#{exception.class}: #{exception.message.strip if exception.message}: #{message}") 28 end
Log a message at level info to all loggers.
# File lib/sequel/database/logging.rb 31 def log_info(message, args=nil) 32 log_each(:info, args ? "#{message}; #{args.inspect}" : message) 33 end
Remove any existing loggers and just use the given logger:
DB.logger = Logger.new($stdout)
# File lib/sequel/database/logging.rb 55 def logger=(logger) 56 @loggers = Array(logger) 57 end
7 - Miscellaneous methods
Constants
CHECK_CONSTRAINT_SQLSTATES | = | %w'23513 23514'.freeze.each(&:freeze) | ||
DEFAULT_DATABASE_ERROR_REGEXPS | = | {}.freeze |
Empty exception regexp to class map, used by default if |
|
DEFAULT_STRING_COLUMN_SIZE | = | 255 |
The general default size for string columns for all |
|
EXTENSIONS | = | {} |
Hash of extension name symbols to callable objects to load the extension into the |
|
FOREIGN_KEY_CONSTRAINT_SQLSTATES | = | %w'23503 23506 23504'.freeze.each(&:freeze) | ||
NOT_NULL_CONSTRAINT_SQLSTATES | = | %w'23502'.freeze.each(&:freeze) | ||
SCHEMA_TYPE_CLASSES | = | {:string=>String, :integer=>Integer, :date=>Date, :datetime=>[Time, DateTime].freeze, :time=>Sequel::SQLTime, :boolean=>[TrueClass, FalseClass].freeze, :float=>Float, :decimal=>BigDecimal, :blob=>Sequel::SQL::Blob}.freeze |
Mapping of schema type symbols to class or arrays of classes for that symbol. |
|
SERIALIZATION_CONSTRAINT_SQLSTATES | = | %w'40001'.freeze.each(&:freeze) | ||
UNIQUE_CONSTRAINT_SQLSTATES | = | %w'23505'.freeze.each(&:freeze) |
Attributes
check_string_typecast_bytesize | [RW] |
Whether to check the bytesize of strings before typecasting (to avoid typecasting strings that would be too long for the given type), true by default. Strings that are too long will raise a typecasting error. |
default_string_column_size | [RW] |
The specific default size of string columns for this |
opts | [R] |
The options hash for this database |
timezone | [W] |
Set the timezone to use for this database, overridding |
Public Class methods
Register a hook that will be run when a new Database
is instantiated. It is called with the new database handle.
# File lib/sequel/database/misc.rb 34 def self.after_initialize(&block) 35 raise Error, "must provide block to after_initialize" unless block 36 Sequel.synchronize do 37 previous = @initialize_hook 38 @initialize_hook = proc do |db| 39 previous.call(db) 40 block.call(db) 41 end 42 end 43 end
Apply an extension to all Database
objects created in the future.
# File lib/sequel/database/misc.rb 46 def self.extension(*extensions) 47 after_initialize{|db| db.extension(*extensions)} 48 end
Constructs a new instance of a database connection with the specified options hash.
Accepts the following options:
:after_connect |
A callable object called after each new connection is made, with the connection object (and server argument if the callable accepts 2 arguments), useful for customizations that you want to apply to all connections. |
:before_preconnect |
Callable that runs after extensions from :preconnect_extensions are loaded, but before any connections are created. |
:cache_schema |
Whether schema should be cached for this |
:check_string_typecast_bytesize |
Whether to check the bytesize of strings before typecasting. |
:connect_sqls |
An array of sql strings to execute on each new connection, after :after_connect runs. |
:default_string_column_size |
The default size of string columns, 255 by default. |
:extensions |
Extensions to load into this |
:keep_reference |
Whether to keep a reference to this instance in Sequel::DATABASES, true by default. |
:logger |
A specific logger to use. |
:loggers |
An array of loggers to use. |
:log_connection_info |
Whether connection information should be logged when logging queries. |
:log_warn_duration |
The number of elapsed seconds after which queries should be logged at warn level. |
:name |
A name to use for the |
:preconnect |
Automatically create the maximum number of connections, so that they don’t need to be created as needed. This is useful when connecting takes a long time and you want to avoid possible latency during runtime. Set to :concurrently to create the connections in separate threads. Otherwise they’ll be created sequentially. |
:preconnect_extensions |
Similar to the :extensions option, but loads the extensions before the connections are made by the :preconnect option. |
: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 |
For sharded connection pools, :after_connect and :connect_sqls can be specified per-shard.
All options given are also passed to the connection pool. Additional options respected by the connection pool are :max_connections, :pool_timeout, :servers, and :servers_hash. See the connection pool documentation for details.
# File lib/sequel/database/misc.rb 138 def initialize(opts = OPTS) 139 @opts ||= opts 140 @opts = connection_pool_default_options.merge(@opts) 141 @loggers = Array(@opts[:logger]) + Array(@opts[:loggers]) 142 @opts[:servers] = {} if @opts[:servers].is_a?(String) 143 @sharded = !!@opts[:servers] 144 @opts[:adapter_class] = self.class 145 @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, Sequel.single_threaded)) 146 @default_string_column_size = @opts[:default_string_column_size] || DEFAULT_STRING_COLUMN_SIZE 147 @check_string_typecast_bytesize = typecast_value_boolean(@opts.fetch(:check_string_typecast_bytesize, true)) 148 149 @schemas = {} 150 @prepared_statements = {} 151 @transactions = {} 152 @symbol_literal_cache = {} 153 154 @timezone = nil 155 156 @dataset_class = dataset_class_default 157 @cache_schema = typecast_value_boolean(@opts.fetch(:cache_schema, true)) 158 @dataset_modules = [] 159 @loaded_extensions = [] 160 @schema_type_classes = SCHEMA_TYPE_CLASSES.dup 161 162 self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info 163 self.log_warn_duration = @opts[:log_warn_duration] 164 self.log_connection_info = typecast_value_boolean(@opts[:log_connection_info]) 165 166 @pool = ConnectionPool.get_pool(self, @opts) 167 168 reset_default_dataset 169 adapter_initialize 170 171 keep_reference = typecast_value_boolean(@opts[:keep_reference]) != false 172 begin 173 Sequel.synchronize{::Sequel::DATABASES.push(self)} if keep_reference 174 Sequel::Database.run_after_initialize(self) 175 176 initialize_load_extensions(:preconnect_extensions) 177 178 if before_preconnect = @opts[:before_preconnect] 179 before_preconnect.call(self) 180 end 181 182 if typecast_value_boolean(@opts[:preconnect]) && @pool.respond_to?(:preconnect, true) 183 concurrent = typecast_value_string(@opts[:preconnect]) == "concurrently" 184 @pool.send(:preconnect, concurrent) 185 end 186 187 initialize_load_extensions(:extensions) 188 test_connection if typecast_value_boolean(@opts.fetch(:test, true)) && respond_to?(:connect, true) 189 rescue 190 Sequel.synchronize{::Sequel::DATABASES.delete(self)} if keep_reference 191 raise 192 end 193 end
Register an extension callback for Database
objects. ext should be the extension name symbol, and mod should either be a Module that the database is extended with, or a callable object called with the database object. If mod is not provided, a block can be provided and is treated as the mod object.
# File lib/sequel/database/misc.rb 55 def self.register_extension(ext, mod=nil, &block) 56 if mod 57 raise(Error, "cannot provide both mod and block to Database.register_extension") if block 58 if mod.is_a?(Module) 59 block = proc{|db| db.extend(mod)} 60 else 61 block = mod 62 end 63 end 64 Sequel.synchronize{EXTENSIONS[ext] = block} 65 end
Run the after_initialize
hook for the given instance
.
# File lib/sequel/database/misc.rb 68 def self.run_after_initialize(instance) 69 @initialize_hook.call(instance) 70 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
# File lib/sequel/database/misc.rb 222 def cast_type_literal(type) 223 type_literal(:type=>type) 224 end
Load an extension into the receiver. In addition to requiring the extension file, this also modifies the database to work with the extension (usually extending it with a module defined in the extension file). If no related extension file exists or the extension does not have specific support for Database
objects, an Error
will be raised. Returns self.
# File lib/sequel/database/misc.rb 231 def extension(*exts) 232 Sequel.extension(*exts) 233 exts.each do |ext| 234 if pr = Sequel.synchronize{EXTENSIONS[ext]} 235 if Sequel.synchronize{@loaded_extensions.include?(ext) ? false : (@loaded_extensions << ext)} 236 pr.call(self) 237 end 238 else 239 raise(Error, "Extension #{ext} does not have specific support handling individual databases (try: Sequel.extension #{ext.inspect})") 240 end 241 end 242 self 243 end
Freeze internal data structures for the Database
instance.
# File lib/sequel/database/misc.rb 196 def freeze 197 valid_connection_sql 198 metadata_dataset 199 @opts.freeze 200 @loggers.freeze 201 @pool.freeze 202 @dataset_class.freeze 203 @dataset_modules.freeze 204 @schema_type_classes.freeze 205 @loaded_extensions.freeze 206 metadata_dataset 207 super 208 end
Convert the given timestamp from the application’s timezone, to the databases’s timezone or the default database timezone if the database does not have a timezone.
# File lib/sequel/database/misc.rb 248 def from_application_timestamp(v) 249 Sequel.convert_output_timestamp(v, timezone) 250 end
Returns a string representation of the database object including the class name and connection URI and options used when connecting (if any).
# File lib/sequel/database/misc.rb 254 def inspect 255 a = [] 256 a << uri.inspect if uri 257 if (oo = opts[:orig_opts]) && !oo.empty? 258 a << oo.inspect 259 end 260 "#<#{self.class}: #{a.join(' ')}>" 261 end
Proxy the literal call to the dataset.
DB.literal(1) # 1 DB.literal(:a) # a DB.literal('a') # 'a'
# File lib/sequel/database/misc.rb 268 def literal(v) 269 schema_utility_dataset.literal(v) 270 end
Return the literalized version of the symbol if cached, or nil if it is not cached.
# File lib/sequel/database/misc.rb 274 def literal_symbol(sym) 275 Sequel.synchronize{@symbol_literal_cache[sym]} 276 end
Set the cached value of the literal symbol.
# File lib/sequel/database/misc.rb 279 def literal_symbol_set(sym, lit) 280 Sequel.synchronize{@symbol_literal_cache[sym] = lit} 281 end
Synchronize access to the prepared statements cache.
# File lib/sequel/database/misc.rb 284 def prepared_statement(name) 285 Sequel.synchronize{prepared_statements[name]} 286 end
Proxy the quote_identifier
method to the dataset, useful for quoting unqualified identifiers for use outside of datasets.
# File lib/sequel/database/misc.rb 291 def quote_identifier(v) 292 schema_utility_dataset.quote_identifier(v) 293 end
Return ruby class or array of classes for the given type symbol.
# File lib/sequel/database/misc.rb 296 def schema_type_class(type) 297 @schema_type_classes[type] 298 end
Default serial primary key options, used by the table creation code.
# File lib/sequel/database/misc.rb 301 def serial_primary_key_options 302 {:primary_key => true, :type => Integer, :auto_increment => true} 303 end
Cache the prepared statement object at the given name.
# File lib/sequel/database/misc.rb 306 def set_prepared_statement(name, ps) 307 Sequel.synchronize{prepared_statements[name] = ps} 308 end
Whether this database instance uses multiple servers, either for sharding or for primary/replica configurations.
# File lib/sequel/database/misc.rb 312 def sharded? 313 @sharded 314 end
The timezone to use for this database, defaulting to Sequel.database_timezone
.
# File lib/sequel/database/misc.rb 317 def timezone 318 @timezone || Sequel.database_timezone 319 end
Convert the given timestamp to the application’s timezone, from the databases’s timezone or the default database timezone if the database does not have a timezone.
# File lib/sequel/database/misc.rb 324 def to_application_timestamp(v) 325 Sequel.convert_timestamp(v, timezone) 326 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 333 def typecast_value(column_type, value) 334 return nil if value.nil? 335 meth = "typecast_value_#{column_type}" 336 begin 337 # Allow calling private methods as per-type typecasting methods are private 338 respond_to?(meth, true) ? send(meth, value) : value 339 rescue ArgumentError, TypeError => e 340 raise Sequel.convert_exception_class(e, InvalidValue) 341 end 342 end
Returns the URI use to connect to the database. If a URI was not used when connecting, returns nil.
# File lib/sequel/database/misc.rb 346 def uri 347 opts[:uri] 348 end
Explicit alias of uri for easier subclassing.
# File lib/sequel/database/misc.rb 351 def url 352 uri 353 end
8 - Methods related to database transactions
Constants
TRANSACTION_ISOLATION_LEVELS | = | {:uncommitted=>'READ UNCOMMITTED'.freeze, :committed=>'READ COMMITTED'.freeze, :repeatable=>'REPEATABLE READ'.freeze, :serializable=>'SERIALIZABLE'.freeze}.freeze |
Attributes
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 |
Public Instance methods
If a transaction is not currently in process, yield to the block immediately. Otherwise, add the block to the list of blocks to call after the currently in progress transaction commits (and only if it commits). Options:
:savepoint |
If currently inside a savepoint, only run this hook on transaction commit if all enclosing savepoints have been released. |
:server |
The server/shard to use. |
# File lib/sequel/database/transactions.rb 31 def after_commit(opts=OPTS, &block) 32 raise Error, "must provide block to after_commit" unless block 33 synchronize(opts[:server]) do |conn| 34 if h = _trans(conn) 35 raise Error, "cannot call after_commit in a prepared transaction" if h[:prepare] 36 if opts[:savepoint] && in_savepoint?(conn) 37 add_savepoint_hook(conn, :after_commit, block) 38 else 39 add_transaction_hook(conn, :after_commit, block) 40 end 41 else 42 yield 43 end 44 end 45 end
If a transaction is not currently in progress, ignore the block. Otherwise, add the block to the list of the blocks to call after the currently in progress transaction rolls back (and only if it rolls back). Options:
:savepoint |
If currently inside a savepoint, run this hook immediately when any enclosing savepoint is rolled back, which may be before the transaction commits or rollsback. |
:server |
The server/shard to use. |
# File lib/sequel/database/transactions.rb 55 def after_rollback(opts=OPTS, &block) 56 raise Error, "must provide block to after_rollback" unless block 57 synchronize(opts[:server]) do |conn| 58 if h = _trans(conn) 59 raise Error, "cannot call after_rollback in a prepared transaction" if h[:prepare] 60 if opts[:savepoint] && in_savepoint?(conn) 61 add_savepoint_hook(conn, :after_rollback, block) 62 else 63 add_transaction_hook(conn, :after_rollback, block) 64 end 65 end 66 end 67 end
Return true if already in a transaction given the options, false otherwise. Respects the :server option for selecting a shard.
# File lib/sequel/database/transactions.rb 113 def in_transaction?(opts=OPTS) 114 synchronize(opts[:server]){|conn| !!_trans(conn)} 115 end
Returns a proc that you can call to check if the transaction has been rolled back. The proc will return nil if the transaction is still in progress, true if the transaction was rolled back, and false if it was committed. Raises an Error
if called outside a transaction. Respects the :server option for selecting a shard.
# File lib/sequel/database/transactions.rb 123 def rollback_checker(opts=OPTS) 124 synchronize(opts[:server]) do |conn| 125 raise Error, "not in a transaction" unless t = _trans(conn) 126 t[:rollback_checker] ||= proc{Sequel.synchronize{t[:rolled_back]}} 127 end 128 end
When exiting the transaction block through methods other than an exception (e.g. normal exit, non-local return, or throw), set the current transaction to rollback instead of committing. This is designed for use in cases where you want to preform a non-local return but also want to rollback instead of committing. Options:
:cancel |
Cancel the current |
:savepoint |
Rollback only the current savepoint if inside a savepoint. Can also be an positive integer value to rollback that number of enclosing savepoints, up to and including the transaction itself. If the database does not support savepoints, this option is ignored and the entire transaction is affected. |
:server |
The server/shard the transaction is being executed on. |
# File lib/sequel/database/transactions.rb 83 def rollback_on_exit(opts=OPTS) 84 synchronize(opts[:server]) do |conn| 85 raise Error, "Cannot call Sequel:: Database#rollback_on_exit unless inside a transaction" unless h = _trans(conn) 86 rollback = !opts[:cancel] 87 88 if supports_savepoints? 89 savepoints = h[:savepoints] 90 91 if level = opts[:savepoint] 92 level = 1 if level == true 93 raise Error, "invalid :savepoint option to Database#rollback_on_exit: #{level.inspect}" unless level.is_a?(Integer) 94 raise Error, "cannot pass nonpositive integer (#{level.inspect}) as :savepoint option to Database#rollback_on_exit" if level < 1 95 level.times do |i| 96 break unless savepoint = savepoints[-1 - i] 97 savepoint[:rollback_on_exit] = rollback 98 end 99 else 100 savepoints[0][:rollback_on_exit] = rollback 101 end 102 else 103 h[:rollback_on_exit] = rollback 104 end 105 end 106 107 nil 108 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 tables do not support transactions.
The following general options are respected:
:auto_savepoint |
Automatically use a savepoint for |
: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. |
:num_retries |
The number of times to retry if the :retry_on option is used. The default is 5 times. Can be set to nil to retry indefinitely, but that is not recommended. |
:before_retry |
Proc to execute before retrying if the :retry_on option is used. Called with two arguments: the number of retry attempts (counting the current one) and the error the last attempt failed with. |
:prepare |
A string to use as the transaction identifier for a prepared transaction (two-phase commit), if the database/adapter supports prepared transactions. |
:retry_on |
An exception class or array of exception classes for which to automatically retry the transaction. Can only be set if not inside an existing transaction. Note that this should not be used unless the entire transaction block is idempotent, as otherwise it can cause non-idempotent behavior to execute multiple times. |
:rollback |
Can be set to :reraise to reraise any Sequel::Rollback exceptions raised, or :always to always rollback even if no exceptions occur (useful for testing). |
:server |
The server to use for the transaction. Set to :default, :read_only, or whatever symbol you used in the connect string when naming your servers. |
:savepoint |
Whether to create a new savepoint for this transaction, only respected if the database/adapter supports savepoints. By default |
:skip_transaction |
If set, do not actually open a transaction or savepoint, just checkout a connection and yield it. |
PostgreSQL specific options:
:deferrable |
(9.1+) If present, set to DEFERRABLE if true or NOT DEFERRABLE if false. |
:read_only |
If present, set to READ ONLY if true or READ WRITE if false. |
:synchronous |
if non-nil, set synchronous_commit appropriately. Valid values true, :on, false, :off, :local (9.1+), and :remote_write (9.2+). |
# File lib/sequel/database/transactions.rb 179 def transaction(opts=OPTS, &block) 180 opts = Hash[opts] 181 if retry_on = opts[:retry_on] 182 tot_retries = opts.fetch(:num_retries, 5) 183 num_retries = 0 184 begin 185 opts[:retry_on] = nil 186 opts[:retrying] = true 187 transaction(opts, &block) 188 rescue *retry_on => e 189 num_retries += 1 190 if tot_retries.nil? || num_retries <= tot_retries 191 opts[:before_retry].call(num_retries, e) if opts[:before_retry] 192 retry 193 end 194 raise 195 end 196 else 197 synchronize(opts[:server]) do |conn| 198 if opts[:skip_transaction] 199 return yield(conn) 200 end 201 202 if opts[:savepoint] == :only 203 if supports_savepoints? 204 if _trans(conn) 205 opts[:savepoint] = true 206 else 207 return yield(conn) 208 end 209 else 210 opts[:savepoint] = false 211 end 212 end 213 214 if opts[:savepoint] && !supports_savepoints? 215 raise Sequel::InvalidOperation, "savepoints not supported on #{database_type}" 216 end 217 218 if already_in_transaction?(conn, opts) 219 if opts[:rollback] == :always && !opts.has_key?(:savepoint) 220 if supports_savepoints? 221 opts[:savepoint] = true 222 else 223 raise Sequel::Error, "cannot set :rollback=>:always transaction option if already inside a transaction" 224 end 225 end 226 227 if opts[:savepoint] != false && (stack = _trans(conn)[:savepoints]) && stack.last[:auto_savepoint] 228 opts[:savepoint] = true 229 end 230 231 unless opts[:savepoint] 232 if opts[:retrying] 233 raise Sequel::Error, "cannot set :retry_on options if you are already inside a transaction" 234 end 235 return yield(conn) 236 end 237 end 238 239 _transaction(conn, opts, &block) 240 end 241 end 242 end
9 - Methods that describe what the database supports
Public Instance methods
Whether the database uses a global namespace for the index, true by default. If false, the indexes are going to be namespaced per table.
# File lib/sequel/database/features.rb 13 def global_index_namespace? 14 true 15 end
Whether the database supports CREATE TABLE IF NOT EXISTS syntax, false by default.
# File lib/sequel/database/features.rb 19 def supports_create_table_if_not_exists? 20 false 21 end
Whether the database supports deferrable constraints, false by default as few databases do.
# File lib/sequel/database/features.rb 25 def supports_deferrable_constraints? 26 false 27 end
Whether the database supports deferrable foreign key constraints, false by default as few databases do.
# File lib/sequel/database/features.rb 31 def supports_deferrable_foreign_key_constraints? 32 supports_deferrable_constraints? 33 end
Whether the database supports DROP TABLE IF EXISTS syntax, false by default.
# File lib/sequel/database/features.rb 37 def supports_drop_table_if_exists? 38 supports_create_table_if_not_exists? 39 end
Whether the database supports Database#foreign_key_list for parsing foreign keys.
# File lib/sequel/database/features.rb 43 def supports_foreign_key_parsing? 44 respond_to?(:foreign_key_list) 45 end
Whether the database supports Database#indexes for parsing indexes.
# File lib/sequel/database/features.rb 48 def supports_index_parsing? 49 respond_to?(:indexes) 50 end
Whether the database supports partial indexes (indexes on a subset of a table), false by default.
# File lib/sequel/database/features.rb 54 def supports_partial_indexes? 55 false 56 end
Whether the database and adapter support prepared transactions (two-phase commit), false by default.
# File lib/sequel/database/features.rb 60 def supports_prepared_transactions? 61 false 62 end
Whether the database and adapter support savepoints, false by default.
# File lib/sequel/database/features.rb 65 def supports_savepoints? 66 false 67 end
Whether the database and adapter support savepoints inside prepared transactions (two-phase commit), false by default.
# File lib/sequel/database/features.rb 71 def supports_savepoints_in_prepared_transactions? 72 supports_prepared_transactions? && supports_savepoints? 73 end
Whether the database supports schema parsing via Database#schema
.
# File lib/sequel/database/features.rb 76 def supports_schema_parsing? 77 respond_to?(:schema_parse_table, true) 78 end
Whether the database supports Database#tables for getting list of tables.
# File lib/sequel/database/features.rb 81 def supports_table_listing? 82 respond_to?(:tables) 83 end
Whether the database and adapter support transaction isolation levels, false by default.
# File lib/sequel/database/features.rb 91 def supports_transaction_isolation_levels? 92 false 93 end
Whether DDL statements work correctly in transactions, false by default.
# File lib/sequel/database/features.rb 96 def supports_transactional_ddl? 97 false 98 end
Whether the database supports Database#views for getting list of views.
# File lib/sequel/database/features.rb 86 def supports_view_listing? 87 respond_to?(:views) 88 end
Whether CREATE VIEW … WITH CHECK OPTION is supported, false by default.
# File lib/sequel/database/features.rb 101 def supports_views_with_check_option? 102 !!view_with_check_option_support 103 end
Whether CREATE VIEW … WITH LOCAL CHECK OPTION is supported, false by default.
# File lib/sequel/database/features.rb 106 def supports_views_with_local_check_option? 107 view_with_check_option_support == :local 108 end