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.
COLUMN_SCHEMA_DATETIME_TYPES | = | [:date, :datetime].freeze |
COLUMN_SCHEMA_STRING_TYPES | = | [:string, :blob, :date, :datetime, :time, :enum, :set, :interval].freeze |
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, line 35 35: def call(ps_name, hash={}, &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, line 42 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, line 49 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, line 56 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, line 65 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 SQL on. |
DB.run("SET some_server_variable = 42")
# File lib/sequel/database/query.rb, line 74 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, line 121 121: 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: end 179: Sequel.synchronize{@schemas[quoted_name] = cols} if cache_schema 180: cols 181: 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, line 191 191: def table_exists?(name) 192: sch, table_name = schema_and_table(name) 193: name = SQL::QualifiedIdentifier.new(sch, table_name) if sch 194: ds = from(name) 195: transaction(:savepoint=>:only){_table_exists?(ds)} 196: true 197: rescue DatabaseError 198: false 199: end
Database transactions make multiple queries atomic, so that either all of the queries take effect or none of them do.
TRANSACTION_ISOLATION_LEVELS | = | {:uncommitted=>'READ UNCOMMITTED'.freeze, :committed=>'READ COMMITTED'.freeze, :repeatable=>'REPEATABLE READ'.freeze, :serializable=>'SERIALIZABLE'.freeze}.freeze |
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. |
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:
:server : | The server/shard to use. |
# File lib/sequel/database/transactions.rb, line 29 29: def after_commit(opts=OPTS, &block) 30: raise Error, "must provide block to after_commit" unless block 31: synchronize(opts[:server]) do |conn| 32: if h = _trans(conn) 33: raise Error, "cannot call after_commit in a prepared transaction" if h[:prepare] 34: add_transaction_hook(conn, :after_commit, block) 35: else 36: yield 37: end 38: end 39: 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:
:server : | The server/shard to use. |
# File lib/sequel/database/transactions.rb, line 46 46: def after_rollback(opts=OPTS, &block) 47: raise Error, "must provide block to after_rollback" unless block 48: synchronize(opts[:server]) do |conn| 49: if h = _trans(conn) 50: raise Error, "cannot call after_rollback in a prepared transaction" if h[:prepare] 51: add_transaction_hook(conn, :after_rollback, block) 52: end 53: end 54: 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, line 59 59: def in_transaction?(opts=OPTS) 60: synchronize(opts[:server]){|conn| !!_trans(conn)} 61: 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, line 69 69: def rollback_checker(opts=OPTS) 70: synchronize(opts[:server]) do |conn| 71: raise Error, "not in a transaction" unless t = _trans(conn) 72: t[:rollback_checker] ||= proc{Sequel.synchronize{t[:rolled_back]}} 73: end 74: 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 Database#transaction calls inside this transaction block. |
: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 rertrying 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 the 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 Sequel will reuse an existing transaction, so if you want to use a savepoint you must use this option. If the surrounding transaction uses :auto_savepoint, you can set this to false to not use a savepoint. If the value given for this option is :only, it will only create a savepoint if it is inside a transaction. |
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, line 123 123: def transaction(opts=OPTS, &block) 124: opts = Hash[opts] 125: if retry_on = opts[:retry_on] 126: tot_retries = opts.fetch(:num_retries, 5) 127: num_retries = 0 unless tot_retries.nil? 128: begin 129: opts[:retry_on] = nil 130: opts[:retrying] = true 131: transaction(opts, &block) 132: rescue *retry_on => e 133: if num_retries 134: num_retries += 1 135: if num_retries <= tot_retries 136: opts[:before_retry].call(num_retries, e) if opts[:before_retry] 137: retry 138: end 139: else 140: retry 141: end 142: raise 143: end 144: else 145: synchronize(opts[:server]) do |conn| 146: if opts[:savepoint] == :only 147: if supports_savepoints? 148: if _trans(conn) 149: opts[:savepoint] = true 150: else 151: return yield(conn) 152: end 153: else 154: opts[:savepoint] = false 155: end 156: end 157: 158: if already_in_transaction?(conn, opts) 159: if opts[:rollback] == :always && !opts.has_key?(:savepoint) 160: if supports_savepoints? 161: opts[:savepoint] = true 162: else 163: raise Sequel::Error, "cannot set :rollback=>:always transaction option if already inside a transaction" 164: end 165: end 166: 167: if opts[:savepoint] != false && (stack = _trans(conn)[:savepoints]) && stack.last 168: opts[:savepoint] = true 169: end 170: 171: unless opts[:savepoint] 172: if opts[:retrying] 173: raise Sequel::Error, "cannot set :retry_on options if you are already inside a transaction" 174: end 175: return yield(conn) 176: end 177: end 178: 179: _transaction(conn, opts, &block) 180: end 181: end 182: end
These methods execute code on the database that modifies the database‘s schema.
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. |
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, line 25 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, line 40 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 and Schema Modification" guide.
# File lib/sequel/database/schema_methods.rb, line 67 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, line 76 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.
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, line 112 112: def create_join_table(hash, options=OPTS) 113: keys = hash.keys.sort 114: create_table(join_table_name(hash, options), options) do 115: keys.each do |key| 116: v = hash[key] 117: unless v.is_a?(Hash) 118: v = {:table=>v} 119: end 120: v[:null] = false unless v.has_key?(:null) 121: foreign_key(key, v) 122: end 123: primary_key(keys) unless options[:no_primary_key] 124: index(keys.reverse, options[:index_options] || {}) unless options[:no_index] 125: end 126: nil 127: end
Forcibly create a join table, attempting to drop it if it already exists, then creating it.
# File lib/sequel/database/schema_methods.rb, line 130 130: def create_join_table!(hash, options=OPTS) 131: drop_table?(join_table_name(hash, options)) 132: create_join_table(hash, options) 133: end
Creates the join table unless it already exists.
# File lib/sequel/database/schema_methods.rb, line 136 136: def create_join_table?(hash, options=OPTS) 137: if supports_create_table_if_not_exists? && options[:no_index] 138: create_join_table(hash, options.merge(:if_not_exists=>true)) 139: elsif !table_exists?(join_table_name(hash, options)) 140: create_join_table(hash, options) 141: end 142: 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, line 231 231: def create_or_replace_view(name, source, options = OPTS) 232: if supports_create_or_replace_view? 233: options = options.merge(:replace=>true) 234: else 235: drop_view(name) rescue nil 236: end 237: 238: create_view(name, source, options) 239: nil 240: 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 SQL string. If this option is used, a block should not be given to the method. |
: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. |
See Schema::CreateTableGenerator and the "Schema Modification" guide.
# File lib/sequel/database/schema_methods.rb, line 179 179: def create_table(name, options=OPTS, &block) 180: remove_cached_schema(name) 181: if sql = options[:as] 182: raise(Error, "can't provide both :as option and block to create_table") if block 183: create_table_as(name, sql, options) 184: else 185: generator = options[:generator] || create_table_generator(&block) 186: create_table_from_generator(name, generator, options) 187: create_table_indexes_from_generator(name, generator, options) 188: end 189: nil 190: 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, line 198 198: def create_table!(name, options=OPTS, &block) 199: drop_table?(name) 200: create_table(name, options, &block) 201: 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, line 208 208: def create_table?(name, options=OPTS, &block) 209: options = options.dup 210: generator = options[:generator] ||= create_table_generator(&block) 211: if generator.indexes.empty? && supports_create_table_if_not_exists? 212: create_table(name, options.merge!(:if_not_exists=>true)) 213: elsif !table_exists?(name) 214: create_table(name, options) 215: end 216: end
Return a new Schema::CreateTableGenerator instance with the receiver as the database and the given block.
# File lib/sequel/database/schema_methods.rb, line 220 220: def create_table_generator(&block) 221: create_table_generator_class.new(self, &block) 222: 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
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 Dataset as the source argument, if should probably call the union method with the all: true and from_self: false options. |
# File lib/sequel/database/schema_methods.rb, line 277 277: def create_view(name, source, options = OPTS) 278: execute_ddl(create_view_sql(name, source, options)) 279: remove_cached_schema(name) 280: nil 281: end
Removes a column from the specified table:
DB.drop_column :items, :category
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 288 288: def drop_column(table, *args) 289: alter_table(table) {drop_column(*args)} 290: end
Removes an index for the given table and column(s):
DB.drop_index :posts, :title DB.drop_index :posts, [:author, :title]
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 298 298: def drop_index(table, columns, options=OPTS) 299: alter_table(table){drop_index(columns, options)} 300: 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, line 307 307: def drop_join_table(hash, options=OPTS) 308: drop_table(join_table_name(hash, options), options) 309: 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, line 316 316: def drop_table(*names) 317: options = names.last.is_a?(Hash) ? names.pop : {} 318: names.each do |n| 319: execute_ddl(drop_table_sql(n, options)) 320: remove_cached_schema(n) 321: end 322: nil 323: 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, line 331 331: def drop_table?(*names) 332: options = names.last.is_a?(Hash) ? names.pop : {} 333: if supports_drop_table_if_exists? 334: options = options.merge(:if_exists=>true) 335: names.each do |name| 336: drop_table(name, options) 337: end 338: else 339: names.each do |name| 340: drop_table(name, options) if table_exists?(name) 341: end 342: end 343: nil 344: 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, line 359 359: def drop_view(*names) 360: options = names.last.is_a?(Hash) ? names.pop : {} 361: names.each do |n| 362: execute_ddl(drop_view_sql(n, options)) 363: remove_cached_schema(n) 364: end 365: nil 366: end
Renames a column in the specified table. This method expects the current column name and the new column name:
DB.rename_column :items, :cntr, :counter
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 385 385: def rename_column(table, *args) 386: alter_table(table) {rename_column(*args)} 387: end
Renames a table:
DB.tables #=> [:items] DB.rename_table :items, :old_items DB.tables #=> [:old_items]
# File lib/sequel/database/schema_methods.rb, line 373 373: def rename_table(name, new_name) 374: execute_ddl(rename_table_sql(name, new_name)) 375: remove_cached_schema(name) 376: nil 377: end
Sets the default value for the given column in the given table:
DB.set_column_default :items, :category, 'perl!'
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 394 394: def set_column_default(table, *args) 395: alter_table(table) {set_column_default(*args)} 396: end
Set the data type for the given column in the given table:
DB.set_column_type :items, :price, :float
See alter_table.
# File lib/sequel/database/schema_methods.rb, line 403 403: def set_column_type(table, *args) 404: alter_table(table) {set_column_type(*args)} 405: end
This methods affect relating to the logging of executed SQL.
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 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. |
Yield to the block, logging any errors at error level to all loggers, and all other queries with the duration at warn or info level.
# File lib/sequel/database/logging.rb, line 37 37: def log_connection_yield(sql, conn, args=nil) 38: return yield if @loggers.empty? 39: sql = "#{connection_info(conn) if conn && log_connection_info}#{sql}#{"; #{args.inspect}" if args}" 40: start = Time.now 41: begin 42: yield 43: rescue => e 44: log_exception(e, sql) 45: raise 46: ensure 47: log_duration(Time.now - start, sql) unless e 48: end 49: end
Log a message at error level, with information about the exception.
# File lib/sequel/database/logging.rb, line 26 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, line 31 31: def log_info(message, args=nil) 32: log_each(:info, args ? "#{message}; #{args.inspect}" : message) 33: end
These methods don‘t fit neatly into another category.
EXTENSIONS | = | {} | Hash of extension name symbols to callable objects to load the extension into the Database object (usually by extending it with a module defined in the extension). | |
DEFAULT_STRING_COLUMN_SIZE | = | 255 | The general default size for string columns for all Sequel::Database instances. | |
DEFAULT_DATABASE_ERROR_REGEXPS | = | {}.freeze | Empty exception regexp to class map, used by default if Sequel doesn‘t have specific support for the database in use. | |
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. | |
NOT_NULL_CONSTRAINT_SQLSTATES | = | %w'23502'.freeze.each(&:freeze) | ||
FOREIGN_KEY_CONSTRAINT_SQLSTATES | = | %w'23503 23506 23504'.freeze.each(&:freeze) | ||
UNIQUE_CONSTRAINT_SQLSTATES | = | %w'23505'.freeze.each(&:freeze) | ||
CHECK_CONSTRAINT_SQLSTATES | = | %w'23513 23514'.freeze.each(&:freeze) | ||
SERIALIZATION_CONSTRAINT_SQLSTATES | = | %w'40001'.freeze.each(&:freeze) |
default_string_column_size | [RW] | The specific default size of string columns for this Sequel::Database, usually 255 by default. |
opts | [R] | The options hash for this database |
timezone | [W] | Set the timezone to use for this database, overridding Sequel.database_timezone. |
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, line 34 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.new do |db| 39: previous.call(db) 40: block.call(db) 41: end 42: end 43: end
Constructs a new instance of a database connection with the specified options hash.
Accepts the following options:
:cache_schema : | Whether schema should be cached for this Database instance |
:default_string_column_size : | The default size of string columns, 255 by default. |
: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 Database object. |
:preconnect : | Whether to automatically connect to the maximum number of servers. Can use a valid of ‘concurrently’ to preconnect in separate threads. |
: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.
# File lib/sequel/database/misc.rb, line 114 114: def initialize(opts = OPTS) 115: @opts ||= opts 116: @opts = connection_pool_default_options.merge(@opts) 117: @loggers = Array(@opts[:logger]) + Array(@opts[:loggers]) 118: @opts[:servers] = {} if @opts[:servers].is_a?(String) 119: @sharded = !!@opts[:servers] 120: @opts[:adapter_class] = self.class 121: @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, Sequel.single_threaded)) 122: @default_string_column_size = @opts[:default_string_column_size] || DEFAULT_STRING_COLUMN_SIZE 123: 124: @schemas = {} 125: @prepared_statements = {} 126: @transactions = {} 127: @symbol_literal_cache = {} 128: 129: @timezone = nil 130: 131: @dataset_class = dataset_class_default 132: @cache_schema = typecast_value_boolean(@opts.fetch(:cache_schema, true)) 133: @dataset_modules = [] 134: @loaded_extensions = [] 135: @schema_type_classes = SCHEMA_TYPE_CLASSES.dup 136: 137: self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info 138: self.log_warn_duration = @opts[:log_warn_duration] 139: self.log_connection_info = typecast_value_boolean(@opts[:log_connection_info]) 140: 141: @pool = ConnectionPool.get_pool(self, @opts) 142: 143: reset_default_dataset 144: adapter_initialize 145: 146: unless typecast_value_boolean(@opts[:keep_reference]) == false 147: Sequel.synchronize{::Sequel::DATABASES.push(self)} 148: end 149: Sequel::Database.run_after_initialize(self) 150: if typecast_value_boolean(@opts[:preconnect]) && @pool.respond_to?(:preconnect, true) 151: concurrent = typecast_value_string(@opts[:preconnect]) == "concurrently" 152: @pool.send(:preconnect, concurrent) 153: end 154: 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, line 55 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, line 68 68: def self.run_after_initialize(instance) 69: @initialize_hook.call(instance) 70: 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, line 190 190: def extension(*exts) 191: Sequel.extension(*exts) 192: exts.each do |ext| 193: if pr = Sequel.synchronize{EXTENSIONS[ext]} 194: unless Sequel.synchronize{@loaded_extensions.include?(ext)} 195: Sequel.synchronize{@loaded_extensions << ext} 196: pr.call(self) 197: end 198: else 199: raise(Error, "Extension #{ext} does not have specific support handling individual databases (try: Sequel.extension #{ext.inspect})") 200: end 201: end 202: self 203: end
Freeze internal data structures for the Database instance.
# File lib/sequel/database/misc.rb, line 157 157: def freeze 158: valid_connection_sql 159: metadata_dataset 160: @opts.freeze 161: @loggers.freeze 162: @pool.freeze 163: @dataset_class.freeze 164: @dataset_modules.freeze 165: @schema_type_classes.freeze 166: @loaded_extensions.freeze 167: metadata_dataset 168: super 169: 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, line 208 208: def from_application_timestamp(v) 209: Sequel.convert_output_timestamp(v, timezone) 210: 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, line 214 214: def inspect 215: a = [] 216: a << uri.inspect if uri 217: if (oo = opts[:orig_opts]) && !oo.empty? 218: a << oo.inspect 219: end 220: "#<#{self.class}: #{a.join(' ')}>" 221: end
Return the literalized version of the symbol if cached, or nil if it is not cached.
# File lib/sequel/database/misc.rb, line 234 234: def literal_symbol(sym) 235: Sequel.synchronize{@symbol_literal_cache[sym]} 236: end
Synchronize access to the prepared statements cache.
# File lib/sequel/database/misc.rb, line 244 244: def prepared_statement(name) 245: Sequel.synchronize{prepared_statements[name]} 246: 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, line 251 251: def quote_identifier(v) 252: schema_utility_dataset.quote_identifier(v) 253: end
Return ruby class or array of classes for the given type symbol.
# File lib/sequel/database/misc.rb, line 256 256: def schema_type_class(type) 257: @schema_type_classes[type] 258: end
Default serial primary key options, used by the table creation code.
# File lib/sequel/database/misc.rb, line 261 261: def serial_primary_key_options 262: {:primary_key => true, :type => Integer, :auto_increment => true} 263: end
Cache the prepared statement object at the given name.
# File lib/sequel/database/misc.rb, line 266 266: def set_prepared_statement(name, ps) 267: Sequel.synchronize{prepared_statements[name] = ps} 268: end
Typecast the value to the given column_type. Calls typecast_value_#{column_type} if the method exists, otherwise returns the value. This method should raise Sequel::InvalidValue if assigned value is invalid.
# File lib/sequel/database/misc.rb, line 293 293: def typecast_value(column_type, value) 294: return nil if value.nil? 295: meth = "typecast_value_#{column_type}" 296: begin 297: # Allow calling private methods as per-type typecasting methods are private 298: respond_to?(meth, true) ? send(meth, value) : value 299: rescue ArgumentError, TypeError => e 300: raise Sequel.convert_exception_class(e, InvalidValue) 301: end 302: end
This methods involve the Database‘s connection pool.
ADAPTERS | = | %w'ado amalgalite ibmdb jdbc mock mysql mysql2 odbc oracle postgres sqlanywhere sqlite tinytds'.map(&:to_sym) | Array of supported database adapters |
Connects to a database. See Sequel.connect.
# File lib/sequel/database/connecting.rb, line 26 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] = (defined?(URI::DEFAULT_PARSER) ? URI::DEFAULT_PARSER : URI).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: db.test_connection if db.send(:typecast_value_boolean, opts.fetch(:test, true)) 59: if block_given? 60: return yield(db) 61: end 62: ensure 63: if block_given? 64: db.disconnect if db 65: Sequel.synchronize{::Sequel::DATABASES.delete(db)} 66: end 67: end 68: db 69: 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, line 77 77: def self.load_adapter(scheme, opts=OPTS) 78: map = opts[:map] || ADAPTER_MAP 79: if subdir = opts[:subdir] 80: file = "#{subdir}/#{scheme}" 81: else 82: file = scheme 83: end 84: 85: unless obj = Sequel.synchronize{map[scheme]} 86: # attempt to load the adapter file 87: begin 88: require "sequel/adapters/#{file}" 89: rescue LoadError => e 90: # If subadapter file doesn't exist, just return, 91: # using the main adapter class without database customizations. 92: return if subdir 93: raise Sequel.convert_exception_class(e, AdapterNotFound) 94: end 95: 96: # make sure we actually loaded the adapter 97: unless obj = Sequel.synchronize{map[scheme]} 98: raise AdapterNotFound, "Could not load #{file} adapter: adapter class not registered in ADAPTER_MAP" 99: end 100: end 101: 102: obj 103: end
Sets the given module as the shared adapter module for the given scheme. Used to register shared adapters for use by the mock adapter. Example:
# in file sequel/adapters/shared/mydb.rb module Sequel::MyDB Sequel::Database.set_shared_adapter_scheme :mydb, self def self.mock_adapter_setup(db) # ... end module DatabaseMethods # ... end module DatasetMethods # ... end end
would allow the mock adapter to return a Database instance that supports the MyDB syntax via:
Sequel.connect('mock://mydb')
# File lib/sequel/database/connecting.rb, line 147 147: def self.set_shared_adapter_scheme(scheme, mod) 148: Sequel.synchronize{SHARED_ADAPTER_MAP[scheme] = mod} 149: end
Returns the scheme symbol for this instance‘s class, which reflects which adapter is being used. In some cases, this can be the same as the database_type (for native adapters), in others (i.e. adapters with subadapters), it will be different.
Sequel.connect('jdbc:postgres://...').adapter_scheme # => :jdbc
# File lib/sequel/database/connecting.rb, line 162 162: def adapter_scheme 163: self.class.adapter_scheme 164: 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, line 174 174: def add_servers(servers) 175: unless sharded? 176: raise Error, "cannot call Database#add_servers on a Database instance that does not use a sharded connection pool" 177: end 178: 179: h = @opts[:servers] 180: Sequel.synchronize{h.merge!(servers)} 181: @pool.add_servers(servers.keys) 182: 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, line 193 193: def database_type 194: adapter_scheme 195: 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, line 207 207: def disconnect(opts = OPTS) 208: pool.disconnect(opts) 209: 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, line 214 214: def disconnect_connection(conn) 215: conn.close 216: 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, line 227 227: def remove_servers(*servers) 228: unless sharded? 229: raise Error, "cannot call Database#remove_servers on a Database instance that does not use a sharded connection pool" 230: end 231: 232: h = @opts[:servers] 233: servers.flatten.each{|s| Sequel.synchronize{h.delete(s)}} 234: @pool.remove_servers(servers) 235: end
Returns true if the database is using a single-threaded connection pool.
# File lib/sequel/database/connecting.rb, line 246 246: def single_threaded? 247: @single_threaded 248: end
Acquires a database connection, yielding it to the passed block. This is useful if you want to make sure the same connection is used for all database queries in the block. It is also useful if you want to gain direct access to the underlying connection object if you need to do something Sequel does not natively support.
If a server option is given, acquires a connection for that specific server, instead of the :default server.
DB.synchronize do |conn| # ... end
# File lib/sequel/database/connecting.rb, line 263 263: def synchronize(server=nil) 264: @pool.hold(server || :default){|conn| yield conn} 265: end
:nocov:
# File lib/sequel/database/connecting.rb, line 268 268: def synchronize(server=nil, &block) 269: @pool.hold(server || :default, &block) 270: end
Attempts to acquire a database connection. Returns true if successful. Will probably raise an Error if unsuccessful. If a server argument is given, attempts to acquire a database connection to the given server/shard.
# File lib/sequel/database/connecting.rb, line 278 278: def test_connection(server=nil) 279: synchronize(server){|conn|} 280: true 281: 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, line 287 287: def valid_connection?(conn) 288: sql = valid_connection_sql 289: begin 290: log_connection_execute(conn, sql) 291: rescue Sequel::DatabaseError, *database_error_classes 292: false 293: else 294: true 295: end 296: end
These methods all return instances of this database‘s dataset class.
Returns a dataset for the database. If the first argument is a string, the method acts as an alias for Database#fetch, returning a dataset for arbitrary SQL, with or without placeholders:
DB['SELECT * FROM items'].all DB['SELECT * FROM items WHERE name = ?', my_name].all
Otherwise, acts as an alias for Database#from, setting the primary table for the dataset:
DB[:items].sql #=> "SELECT * FROM items"
# File lib/sequel/database/dataset.rb, line 21 21: def [](*args) 22: args.first.is_a?(String) ? fetch(*args) : from(*args) 23: 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
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, line 49 49: def fetch(sql, *args, &block) 50: ds = @default_dataset.with_sql(sql, *args) 51: ds.each(&block) if block 52: ds 53: 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, line 60 60: def from(*args, &block) 61: if block 62: @default_dataset.from(*args, &block) 63: elsif args.length == 1 && (table = args[0]).is_a?(Symbol) 64: @default_dataset.send(:cached_dataset, "_from_#{table}_ds""_from_#{table}_ds"){@default_dataset.from(table)} 65: else 66: @default_dataset.from(*args) 67: end 68: 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, line 75 75: def select(*args, &block) 76: @default_dataset.select(*args, &block) 77: end
These methods all return booleans, with most describing whether or not the database supprots a given feature.
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, line 13 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, line 19 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, line 25 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, line 31 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, line 37 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, line 43 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, line 48 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, line 54 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, line 60 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, line 65 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, line 71 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, line 76 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, line 81 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, line 91 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, line 96 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, line 86 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, line 101 101: def supports_views_with_check_option? 102: !!view_with_check_option_support 103: end
This methods change the default behavior of this database‘s datasets.
OPTS | = | Sequel::OPTS |
conversion_procs | [R] | Hash of conversion procs for the current database |
convert_invalid_date_time | [R] | By default, Sequel raises an exception if in invalid date or time is used. However, if this is set to nil or :nil, the adapter treats dates like 0000-00-00 and times like 838:00:00 as nil values. If set to :string, it returns the strings as is. |
convert_tinyint_to_bool | [RW] | Whether to convert tinyint columns to bool for this database |
convert_tinyint_to_bool | [R] | Whether to convert tinyint columns to bool for the current database |
dataset_class | [R] | The class to use for creating datasets. Should respond to new with the Database argument as the first argument, and an optional options hash. |
Connect to the database. In addition to the usual database options, the following options have effect:
:auto_is_null : | Set to true to use MySQL default behavior of having a filter for an autoincrement column equals NULL to return the last inserted row. |
:charset : | Same as :encoding (:encoding takes precendence) |
:compress : | Set to false to not compress results from the server |
:config_default_group : | The default group to read from the in the MySQL config file. |
:config_local_infile : | If provided, sets the Mysql::OPT_LOCAL_INFILE option on the connection with the given value. |
:connect_timeout : | Set the timeout in seconds before a connection attempt is abandoned. |
:encoding : | Set all the related character sets for this connection (connection, client, database, server, and results). |
:read_timeout : | Set the timeout in seconds for reading back results to a query. |
:socket : | Use a unix socket file instead of connecting via TCP/IP. |
:timeout : | Set the timeout in seconds before the server will disconnect this connection (a.k.a @@wait_timeout). |
# File lib/sequel/adapters/mysql.rb, line 73 73: def connect(server) 74: opts = server_opts(server) 75: conn = Mysql.init 76: conn.options(Mysql::READ_DEFAULT_GROUP, opts[:config_default_group] || "client") 77: conn.options(Mysql::OPT_LOCAL_INFILE, opts[:config_local_infile]) if opts.has_key?(:config_local_infile) 78: conn.ssl_set(opts[:sslkey], opts[:sslcert], opts[:sslca], opts[:sslcapath], opts[:sslcipher]) if opts[:sslca] || opts[:sslkey] 79: if encoding = opts[:encoding] || opts[:charset] 80: # Set encoding before connecting so that the mysql driver knows what 81: # encoding we want to use, but this can be overridden by READ_DEFAULT_GROUP. 82: conn.options(Mysql::SET_CHARSET_NAME, encoding) 83: end 84: if read_timeout = opts[:read_timeout] and defined? Mysql::OPT_READ_TIMEOUT 85: conn.options(Mysql::OPT_READ_TIMEOUT, read_timeout) 86: end 87: if connect_timeout = opts[:connect_timeout] and defined? Mysql::OPT_CONNECT_TIMEOUT 88: conn.options(Mysql::OPT_CONNECT_TIMEOUT, connect_timeout) 89: end 90: conn.real_connect( 91: opts[:host] || 'localhost', 92: opts[:user], 93: opts[:password], 94: opts[:database], 95: (opts[:port].to_i if opts[:port]), 96: opts[:socket], 97: Mysql::CLIENT_MULTI_RESULTS + 98: Mysql::CLIENT_MULTI_STATEMENTS + 99: (opts[:compress] == false ? 0 : Mysql::CLIENT_COMPRESS) 100: ) 101: sqls = mysql_connection_setting_sqls 102: 103: # Set encoding a slightly different way after connecting, 104: # in case the READ_DEFAULT_GROUP overrode the provided encoding. 105: # Doesn't work across implicit reconnects, but Sequel doesn't turn on 106: # that feature. 107: sqls.unshift("SET NAMES #{literal(encoding.to_s)}") if encoding 108: 109: sqls.each{|sql| log_connection_yield(sql, conn){conn.query(sql)}} 110: 111: add_prepared_statements_cache(conn) 112: conn 113: end
Connect to the database. In addition to the usual database options, the following options have effect:
:auto_is_null : | Set to true to use MySQL default behavior of having a filter for an autoincrement column equals NULL to return the last inserted row. |
:charset : | Same as :encoding (:encoding takes precendence) |
:encoding : | Set all the related character sets for this connection (connection, client, database, server, and results). |
The options hash is also passed to mysql2, and can include mysql2 options such as :local_infile.
# File lib/sequel/adapters/mysql2.rb, line 37 37: def connect(server) 38: opts = server_opts(server) 39: opts[:host] ||= 'localhost' 40: opts[:username] ||= opts.delete(:user) 41: opts[:flags] ||= 0 42: opts[:flags] |= ::Mysql2::Client::FOUND_ROWS if ::Mysql2::Client.const_defined?(:FOUND_ROWS) 43: opts[:encoding] ||= opts[:charset] 44: conn = ::Mysql2::Client.new(opts) 45: conn.query_options.merge!(:symbolize_keys=>true, :cache_rows=>false) 46: 47: if NativePreparedStatements 48: conn.instance_variable_set(:@sequel_default_query_options, conn.query_options.dup) 49: end 50: 51: sqls = mysql_connection_setting_sqls 52: 53: # Set encoding a slightly different way after connecting, 54: # in case the READ_DEFAULT_GROUP overrode the provided encoding. 55: # Doesn't work across implicit reconnects, but Sequel doesn't turn on 56: # that feature. 57: if encoding = opts[:encoding] 58: sqls.unshift("SET NAMES #{conn.escape(encoding.to_s)}") 59: end 60: 61: sqls.each{|sql| log_connection_yield(sql, conn){conn.query(sql)}} 62: 63: add_prepared_statements_cache(conn) 64: conn 65: end
Modify the type translators for the date, time, and timestamp types depending on the value given.
# File lib/sequel/adapters/mysql.rb, line 123 123: def convert_invalid_date_time=(v) 124: m0 = ::Sequel.method(:string_to_time) 125: @conversion_procs[11] = (v != false) ? lambda{|val| convert_date_time(val, &m0)} : m0 126: m1 = ::Sequel.method(:string_to_date) 127: m = (v != false) ? lambda{|val| convert_date_time(val, &m1)} : m1 128: [10, 14].each{|i| @conversion_procs[i] = m} 129: m2 = method(:to_application_timestamp) 130: m = (v != false) ? lambda{|val| convert_date_time(val, &m2)} : m2 131: [7, 12].each{|i| @conversion_procs[i] = m} 132: @convert_invalid_date_time = v 133: end
Modify the type translator used for the tinyint type based on the value given.
# File lib/sequel/adapters/mysql.rb, line 137 137: def convert_tinyint_to_bool=(v) 138: @conversion_procs[1] = TYPE_TRANSLATOR.method(v ? :boolean : :integer) 139: @convert_tinyint_to_bool = v 140: end
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, line 18 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
# File lib/sequel/adapters/mysql.rb, line 115 115: def disconnect_connection(c) 116: c.close 117: rescue Mysql::Error 118: nil 119: end
# File lib/sequel/adapters/mysql2.rb, line 67 67: def execute_dui(sql, opts=OPTS) 68: execute(sql, opts){|c| return c.affected_rows} 69: end
# File lib/sequel/adapters/mysql.rb, line 142 142: def execute_dui(sql, opts=OPTS) 143: execute(sql, opts){|c| return affected_rows(c)} 144: end
# File lib/sequel/adapters/mysql.rb, line 146 146: def execute_insert(sql, opts=OPTS) 147: execute(sql, opts){|c| return c.insert_id} 148: end
# File lib/sequel/adapters/mysql2.rb, line 71 71: def execute_insert(sql, opts=OPTS) 72: execute(sql, opts){|c| return c.last_id} 73: 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, line 62 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
# File lib/sequel/adapters/mysql.rb, line 150 150: def freeze 151: server_version 152: @conversion_procs.freeze 153: super 154: end
This methods generally execute SQL code on the database server.