class Sequel::Database

  1. lib/sequel/core.rb
  2. lib/sequel/database.rb
  3. lib/sequel/database/connecting.rb
  4. lib/sequel/database/dataset.rb
  5. lib/sequel/database/dataset_defaults.rb
  6. lib/sequel/database/features.rb
  7. lib/sequel/database/logging.rb
  8. lib/sequel/database/misc.rb
  9. lib/sequel/database/query.rb
  10. lib/sequel/database/schema_methods.rb
  11. lib/sequel/database/transactions.rb
  12. show all
Superclass: Object

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

  1. adapter_class
  2. adapter_scheme
  3. after_initialize
  4. connect
  5. extension
  6. load_adapter
  7. new
  8. register_extension
  9. run_after_initialize
  10. set_shared_adapter_scheme

Public Instance

  1. <<
  2. []
  3. adapter_scheme
  4. add_column
  5. add_index
  6. add_servers
  7. after_commit
  8. after_rollback
  9. alter_table
  10. alter_table_generator
  11. cache_schema
  12. call
  13. cast_type_literal
  14. create_join_table
  15. create_join_table!
  16. create_join_table?
  17. create_or_replace_view
  18. create_table
  19. create_table!
  20. create_table?
  21. create_table_generator
  22. create_view
  23. database_type
  24. dataset
  25. dataset_class
  26. dataset_class=
  27. default_string_column_size
  28. disconnect
  29. disconnect_connection
  30. drop_column
  31. drop_index
  32. drop_join_table
  33. drop_table
  34. drop_table?
  35. drop_view
  36. execute_ddl
  37. execute_dui
  38. execute_insert
  39. extend_datasets
  40. extension
  41. fetch
  42. freeze
  43. from
  44. from_application_timestamp
  45. get
  46. global_index_namespace?
  47. in_transaction?
  48. inspect
  49. literal
  50. literal_symbol
  51. literal_symbol_set
  52. log_connection_info
  53. log_connection_yield
  54. log_exception
  55. log_info
  56. log_warn_duration
  57. logger=
  58. loggers
  59. opts
  60. pool
  61. prepared_statement
  62. prepared_statements
  63. quote_identifier
  64. remove_servers
  65. rename_column
  66. rename_table
  67. rollback_checker
  68. run
  69. schema
  70. schema_type_class
  71. select
  72. serial_primary_key_options
  73. servers
  74. set_column_default
  75. set_column_type
  76. set_prepared_statement
  77. sharded?
  78. single_threaded?
  79. sql_log_level
  80. supports_create_table_if_not_exists?
  81. supports_deferrable_constraints?
  82. supports_deferrable_foreign_key_constraints?
  83. supports_drop_table_if_exists?
  84. supports_foreign_key_parsing?
  85. supports_index_parsing?
  86. supports_partial_indexes?
  87. supports_prepared_transactions?
  88. supports_savepoints?
  89. supports_savepoints_in_prepared_transactions?
  90. supports_schema_parsing?
  91. supports_table_listing?
  92. supports_transaction_isolation_levels?
  93. supports_transactional_ddl?
  94. supports_view_listing?
  95. supports_views_with_check_option?
  96. supports_views_with_local_check_option?
  97. synchronize
  98. table_exists?
  99. test_connection
  100. timezone
  101. timezone
  102. to_application_timestamp
  103. transaction
  104. transaction_isolation_level
  105. typecast_value
  106. uri
  107. url
  108. valid_connection?

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  

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

<< (sql)

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"
[show source]
# File lib/sequel/database/query.rb, line 24
def <<(sql)
  run(sql)
  self
end
call (ps_name, hash={}, &block)

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
[show source]
# File lib/sequel/database/query.rb, line 34
def call(ps_name, hash={}, &block)
  prepared_statement(ps_name).call(hash, &block)
end
execute_ddl (sql, opts=OPTS, &block)

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.

[show source]
# File lib/sequel/database/query.rb, line 41
def execute_ddl(sql, opts=OPTS, &block)
  execute_dui(sql, opts, &block)
end
execute_dui (sql, opts=OPTS, &block)

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.

[show source]
# File lib/sequel/database/query.rb, line 48
def execute_dui(sql, opts=OPTS, &block)
  execute(sql, opts, &block)
end
execute_insert (sql, opts=OPTS, &block)

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.

[show source]
# File lib/sequel/database/query.rb, line 55
def execute_insert(sql, opts=OPTS, &block)
  execute_dui(sql, opts, &block)
end
get (*args, &block)

Returns a single value from the database, see Sequel::Dataset#get.

DB.get(1) # SELECT 1
# => 1
DB.get{server_version.function} # SELECT server_version()
[show source]
# File lib/sequel/database/query.rb, line 64
def get(*args, &block)
  @default_dataset.get(*args, &block)
end
run (sql, opts=OPTS)

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")
[show source]
# File lib/sequel/database/query.rb, line 73
def run(sql, opts=OPTS)
  sql = literal(sql) if sql.is_a?(SQL::PlaceholderLiteralString)
  execute_ddl(sql, opts)
  nil
end
schema (table, opts=OPTS)

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}]]
[show source]
# File lib/sequel/database/query.rb, line 120
def schema(table, opts=OPTS)
  raise(Error, 'schema parsing is not implemented on this database') unless supports_schema_parsing?

  opts = opts.dup
  tab = if table.is_a?(Dataset)
    o = table.opts
    from = o[:from]
    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)
    table.first_source_table
  else
    table
  end

  qualifiers = split_qualifiers(tab)
  table_name = qualifiers.pop
  sch = qualifiers.pop
  information_schema_schema = case qualifiers.length
  when 1
    Sequel.identifier(*qualifiers)
  when 2
    Sequel.qualify(*qualifiers)
  end

  if table.is_a?(Dataset)
    quoted_name = table.literal(tab)
    opts[:dataset] = table
  else
    quoted_name = schema_utility_dataset.literal(table)
  end

  opts[:schema] = sch if sch && !opts.include?(:schema)
  opts[:information_schema_schema] = information_schema_schema if information_schema_schema && !opts.include?(:information_schema_schema)

  Sequel.synchronize{@schemas.delete(quoted_name)} if opts[:reload]
  if v = Sequel.synchronize{@schemas[quoted_name]}
    return v
  end

  cols = schema_parse_table(table_name, opts)
  raise(Error, "schema parsing returned no columns, table #{table_name.inspect} probably doesn't exist") if cols.nil? || cols.empty?

  primary_keys = 0
  auto_increment_set = false
  cols.each do |_,c|
    auto_increment_set = true if c.has_key?(:auto_increment)
    primary_keys += 1 if c[:primary_key]
  end

  cols.each do |_,c|
    c[:ruby_default] = column_schema_to_ruby_default(c[:default], c[:type]) unless c.has_key?(:ruby_default)
    if c[:primary_key] && !auto_increment_set
      # If adapter didn't set it, assume that integer primary keys are auto incrementing
      c[:auto_increment] = primary_keys == 1 && !!(c[:db_type] =~ /int/io)
    end
    if !c[:max_length] && c[:type] == :string && (max_length = column_schema_max_length(c[:db_type]))
      c[:max_length] = max_length
    end
  end
  Sequel.synchronize{@schemas[quoted_name] = cols} if cache_schema
  cols
end
table_exists? (name)

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.

[show source]
# File lib/sequel/database/query.rb, line 190
def table_exists?(name)
  sch, table_name = schema_and_table(name)
  name = SQL::QualifiedIdentifier.new(sch, table_name) if sch
  ds = from(name)
  transaction(:savepoint=>:only){_table_exists?(ds)}
  true
rescue DatabaseError
  false
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

add_column (table, *args)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 24
def add_column(table, *args)
  alter_table(table) {add_column(*args)}
end
add_index (table, columns, options=OPTS)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 39
def add_index(table, columns, options=OPTS)
  e = options[:ignore_errors]
  begin
    alter_table(table){add_index(columns, options)}
  rescue DatabaseError
    raise unless e
  end
  nil
end
alter_table (name, &block)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 66
def alter_table(name, &block)
  generator = alter_table_generator(&block)
  remove_cached_schema(name)
  apply_alter_table_generator(name, generator)
  nil
end
alter_table_generator (&block)

Return a new Schema::AlterTableGenerator instance with the receiver as the database and the given block.

[show source]
# File lib/sequel/database/schema_methods.rb, line 75
def alter_table_generator(&block)
  alter_table_generator_class.new(self, &block)
end
create_join_table (hash, options=OPTS)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 111
def create_join_table(hash, options=OPTS)
  keys = hash.keys.sort
  create_table(join_table_name(hash, options), options) do
    keys.each do |key|
      v = hash[key]
      unless v.is_a?(Hash)
        v = {:table=>v}
      end
      v[:null] = false unless v.has_key?(:null)
      foreign_key(key, v)
    end
    primary_key(keys) unless options[:no_primary_key]
    index(keys.reverse, options[:index_options] || {}) unless options[:no_index]
  end
  nil
end
create_join_table! (hash, options=OPTS)

Forcibly create a join table, attempting to drop it if it already exists, then creating it.

[show source]
# File lib/sequel/database/schema_methods.rb, line 129
def create_join_table!(hash, options=OPTS)
  drop_table?(join_table_name(hash, options))
  create_join_table(hash, options)
end
create_join_table? (hash, options=OPTS)

Creates the join table unless it already exists.

[show source]
# File lib/sequel/database/schema_methods.rb, line 135
def create_join_table?(hash, options=OPTS)
  if supports_create_table_if_not_exists? && options[:no_index]
    create_join_table(hash, options.merge(:if_not_exists=>true))
  elsif !table_exists?(join_table_name(hash, options))
    create_join_table(hash, options)
  end
end
create_or_replace_view (name, source, options = OPTS)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 230
def create_or_replace_view(name, source, options = OPTS)
  if supports_create_or_replace_view?
    options = options.merge(:replace=>true)
  else
    drop_view(name) rescue nil
  end

  create_view(name, source, options)
  nil
end
create_table (name, options=OPTS, &block)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 178
def create_table(name, options=OPTS, &block)
  remove_cached_schema(name)
  if sql = options[:as]
    raise(Error, "can't provide both :as option and block to create_table") if block
    create_table_as(name, sql, options)
  else
    generator = options[:generator] || create_table_generator(&block)
    create_table_from_generator(name, generator, options)
    create_table_indexes_from_generator(name, generator, options)
  end
  nil
end
create_table! (name, options=OPTS, &block)

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)
[show source]
# File lib/sequel/database/schema_methods.rb, line 197
def create_table!(name, options=OPTS, &block)
  drop_table?(name)
  create_table(name, options, &block)
end
create_table? (name, options=OPTS, &block)

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
[show source]
# File lib/sequel/database/schema_methods.rb, line 207
def create_table?(name, options=OPTS, &block)
  options = options.dup
  generator = options[:generator] ||= create_table_generator(&block)
  if generator.indexes.empty? && supports_create_table_if_not_exists?
    create_table(name, options.merge!(:if_not_exists=>true))
  elsif !table_exists?(name)
    create_table(name, options)
  end
end
create_table_generator (&block)

Return a new Schema::CreateTableGenerator instance with the receiver as the database and the given block.

[show source]
# File lib/sequel/database/schema_methods.rb, line 219
def create_table_generator(&block)
  create_table_generator_class.new(self, &block)
end
create_view (name, source, options = OPTS)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 276
def create_view(name, source, options = OPTS)
  execute_ddl(create_view_sql(name, source, options))
  remove_cached_schema(name)
  nil
end
drop_column (table, *args)

Removes a column from the specified table:

DB.drop_column :items, :category

See alter_table.

[show source]
# File lib/sequel/database/schema_methods.rb, line 287
def drop_column(table, *args)
  alter_table(table) {drop_column(*args)}
end
drop_index (table, columns, options=OPTS)

Removes an index for the given table and column(s):

DB.drop_index :posts, :title
DB.drop_index :posts, [:author, :title]

See alter_table.

[show source]
# File lib/sequel/database/schema_methods.rb, line 297
def drop_index(table, columns, options=OPTS)
  alter_table(table){drop_index(columns, options)}
end
drop_join_table (hash, options=OPTS)

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
[show source]
# File lib/sequel/database/schema_methods.rb, line 306
def drop_join_table(hash, options=OPTS)
  drop_table(join_table_name(hash, options), options)
end
drop_table (*names)

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)
[show source]
# File lib/sequel/database/schema_methods.rb, line 315
def drop_table(*names)
  options = names.last.is_a?(Hash) ? names.pop : {}
  names.each do |n|
    execute_ddl(drop_table_sql(n, options))
    remove_cached_schema(n)
  end
  nil
end
drop_table? (*names)

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
[show source]
# File lib/sequel/database/schema_methods.rb, line 330
def drop_table?(*names)
  options = names.last.is_a?(Hash) ? names.pop : {}
  if supports_drop_table_if_exists?
    options = options.merge(:if_exists=>true)
    names.each do |name|
      drop_table(name, options)
    end
  else
    names.each do |name|
      drop_table(name, options) if table_exists?(name)
    end
  end
  nil
end
drop_view (*names)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 358
def drop_view(*names)
  options = names.last.is_a?(Hash) ? names.pop : {}
  names.each do |n|
    execute_ddl(drop_view_sql(n, options))
    remove_cached_schema(n)
  end
  nil
end
rename_column (table, *args)

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.

[show source]
# File lib/sequel/database/schema_methods.rb, line 384
def rename_column(table, *args)
  alter_table(table) {rename_column(*args)}
end
rename_table (name, new_name)

Renames a table:

DB.tables #=> [:items]
DB.rename_table :items, :old_items
DB.tables #=> [:old_items]
[show source]
# File lib/sequel/database/schema_methods.rb, line 372
def rename_table(name, new_name)
  execute_ddl(rename_table_sql(name, new_name))
  remove_cached_schema(name)
  nil
end
set_column_default (table, *args)

Sets the default value for the given column in the given table:

DB.set_column_default :items, :category, 'perl!'

See alter_table.

[show source]
# File lib/sequel/database/schema_methods.rb, line 393
def set_column_default(table, *args)
  alter_table(table) {set_column_default(*args)}
end
set_column_type (table, *args)

Set the data type for the given column in the given table:

DB.set_column_type :items, :price, :float

See alter_table.

[show source]
# File lib/sequel/database/schema_methods.rb, line 402
def set_column_type(table, *args)
  alter_table(table) {set_column_type(*args)}
end

3 - Methods that create datasets

Public Instance methods

[] (*args)

Returns a dataset for the database. If the first argument is a string, the method acts as an alias for #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 #from, setting the primary table for the dataset:

DB[:items].sql #=> "SELECT * FROM items"
[show source]
# File lib/sequel/database/dataset.rb, line 20
def [](*args)
  args.first.is_a?(String) ? fetch(*args) : from(*args)
end
dataset ()

Returns a blank dataset for this database.

DB.dataset # SELECT *
DB.dataset.from(:items) # SELECT * FROM items
[show source]
# File lib/sequel/database/dataset.rb, line 28
def dataset
  @dataset_class.new(self)
end
fetch (sql, *args, &block)

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 Sequel::Dataset#with_sql regarding datasets using custom SQL and the methods that can be called on them.

[show source]
# File lib/sequel/database/dataset.rb, line 48
def fetch(sql, *args, &block)
  ds = @default_dataset.with_sql(sql, *args)
  ds.each(&block) if block
  ds
end
from (*args, &block)

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
[show source]
# File lib/sequel/database/dataset.rb, line 59
def from(*args, &block)
  if block
    @default_dataset.from(*args, &block)
  elsif args.length == 1 && (table = args[0]).is_a?(Symbol)
    @default_dataset.send(:cached_dataset, :"_from_#{table}_ds"){@default_dataset.from(table)}
  else
    @default_dataset.from(*args)
  end
end
select (*args, &block)

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
[show source]
# File lib/sequel/database/dataset.rb, line 74
def select(*args, &block)
  @default_dataset.select(*args, &block)
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'.map(&:to_sym)  

Array of supported database adapters

Attributes

pool [R]

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

Public Class methods

adapter_class (scheme)

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

[show source]
# File lib/sequel/database/connecting.rb, line 15
def self.adapter_class(scheme)
  scheme.is_a?(Class) ? scheme : load_adapter(scheme.to_sym)
end
adapter_scheme ()

Returns the scheme symbol for the Database class.

[show source]
# File lib/sequel/database/connecting.rb, line 20
def self.adapter_scheme
  @scheme
end
connect (conn_string, opts = OPTS)

Connects to a database. See Sequel.connect.

[show source]
# File lib/sequel/database/connecting.rb, line 25
def self.connect(conn_string, opts = OPTS)
  case conn_string
  when String
    if conn_string.start_with?('jdbc:')
      c = adapter_class(:jdbc)
      opts = opts.merge(:orig_opts=>opts.dup)
      opts = {:uri=>conn_string}.merge!(opts)
    else
      uri = URI.parse(conn_string)
      scheme = uri.scheme
      c = adapter_class(scheme)
      uri_options = c.send(:uri_to_options, uri)
      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?
      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)}
      opts = uri_options.merge(opts).merge!(:orig_opts=>opts.dup, :uri=>conn_string, :adapter=>scheme)
    end
  when Hash
    opts = conn_string.merge(opts)
    opts = opts.merge(:orig_opts=>opts.dup)
    c = adapter_class(opts[:adapter_class] || opts[:adapter] || opts['adapter'])
  else
    raise Error, "Sequel::Database.connect takes either a Hash or a String, given: #{conn_string.inspect}"
  end

  opts = opts.inject({}) do |m, (k,v)|
    k = :user if k.to_s == 'username'
    m[k.to_sym] = v
    m
  end

  begin
    db = c.new(opts)
    db.test_connection if db.send(:typecast_value_boolean, opts.fetch(:test, true))
    if block_given?
      return yield(db)
    end
  ensure
    if block_given?
      db.disconnect if db
      Sequel.synchronize{::Sequel::DATABASES.delete(db)}
    end
  end
  db
end
load_adapter (scheme, opts=OPTS)

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.

[show source]
# File lib/sequel/database/connecting.rb, line 76
def self.load_adapter(scheme, opts=OPTS)
  map = opts[:map] || ADAPTER_MAP
  if subdir = opts[:subdir]
    file = "#{subdir}/#{scheme}"
  else
    file = scheme
  end
  
  unless obj = Sequel.synchronize{map[scheme]}
    # attempt to load the adapter file
    begin
      require "sequel/adapters/#{file}"
    rescue LoadError => e
      # If subadapter file doesn't exist, just return, 
      # using the main adapter class without database customizations.
      return if subdir
      raise Sequel.convert_exception_class(e, AdapterNotFound)
    end
    
    # make sure we actually loaded the adapter
    unless obj = Sequel.synchronize{map[scheme]}
      raise AdapterNotFound, "Could not load #{file} adapter: adapter class not registered in ADAPTER_MAP"
    end
  end

  obj
end
set_shared_adapter_scheme (scheme, mod)

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')
[show source]
# File lib/sequel/database/connecting.rb, line 146
def self.set_shared_adapter_scheme(scheme, mod)
  Sequel.synchronize{SHARED_ADAPTER_MAP[scheme] = mod}
end

Public Instance methods

adapter_scheme ()

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
[show source]
# File lib/sequel/database/connecting.rb, line 161
def adapter_scheme
  self.class.adapter_scheme
end
add_servers (servers)

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"})
[show source]
# File lib/sequel/database/connecting.rb, line 173
def add_servers(servers)
  unless sharded?
    raise Error, "cannot call Database#add_servers on a Database instance that does not use a sharded connection pool"
  end

  h = @opts[:servers]
  Sequel.synchronize{h.merge!(servers)}
  @pool.add_servers(servers.keys)
end
database_type ()

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
[show source]
# File lib/sequel/database/connecting.rb, line 192
def database_type
  adapter_scheme
end
disconnect (opts = OPTS)

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
[show source]
# File lib/sequel/database/connecting.rb, line 206
def disconnect(opts = OPTS)
  pool.disconnect(opts)
end
disconnect_connection (conn)

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.

[show source]
# File lib/sequel/database/connecting.rb, line 213
def disconnect_connection(conn)
  conn.close
end
remove_servers (*servers)

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)
[show source]
# File lib/sequel/database/connecting.rb, line 226
def remove_servers(*servers)
  unless sharded?
    raise Error, "cannot call Database#remove_servers on a Database instance that does not use a sharded connection pool"
  end

  h = @opts[:servers]
  servers.flatten.each{|s| Sequel.synchronize{h.delete(s)}}
  @pool.remove_servers(servers)
end
servers ()

An array of servers/shards for this Database object.

DB.servers # Unsharded: => [:default]
DB.servers # Sharded:   => [:default, :server1, :server2]
[show source]
# File lib/sequel/database/connecting.rb, line 240
def servers
  pool.servers
end
single_threaded? ()

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

[show source]
# File lib/sequel/database/connecting.rb, line 245
def single_threaded?
  @single_threaded
end
synchronize (server=nil)

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
[show source]
# File lib/sequel/database/connecting.rb, line 262
def synchronize(server=nil)
  @pool.hold(server || :default){|conn| yield conn}
end
test_connection (server=nil)

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.

[show source]
# File lib/sequel/database/connecting.rb, line 277
def test_connection(server=nil)
  synchronize(server){|conn|}
  true
end
valid_connection? (conn)

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.

[show source]
# File lib/sequel/database/connecting.rb, line 286
def valid_connection?(conn)
  sql = valid_connection_sql
  begin
    log_connection_execute(conn, sql)
  rescue Sequel::DatabaseError, *database_error_classes
    false
  else
    true
  end
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 Database argument as the first argument, and an optional options hash.

Public Instance methods

dataset_class= (c)

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.

[show source]
# File lib/sequel/database/dataset_defaults.rb, line 17
def dataset_class=(c)
  unless @dataset_modules.empty?
    c = Class.new(c)
    @dataset_modules.each{|m| c.send(:include, m)}
  end
  @dataset_class = c
  reset_default_dataset
end
extend_datasets (mod=nil, &block)

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
[show source]
# File lib/sequel/database/dataset_defaults.rb, line 61
def extend_datasets(mod=nil, &block)
  raise(Error, "must provide either mod or block, not both") if mod && block
  mod = Dataset::DatasetModule.new(&block) if block
  if @dataset_modules.empty?
   @dataset_modules = [mod]
   @dataset_class = Class.new(@dataset_class)
  else
   @dataset_modules << mod
  end
  @dataset_class.send(:include, mod)
  reset_default_dataset
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 loggers to use for this database.

sql_log_level [RW]

Log level at which to log SQL queries. This is actually the method sent to the logger, so it should be the method name symbol. The default is :info, it can be set to :debug to log at DEBUG level.

Public Instance methods

log_connection_yield (sql, conn, args=nil)

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.

[show source]
# File lib/sequel/database/logging.rb, line 36
def log_connection_yield(sql, conn, args=nil)
  return yield if @loggers.empty?
  sql = "#{connection_info(conn) if conn && log_connection_info}#{sql}#{"; #{args.inspect}" if args}"
  start = Time.now
  begin
    yield
  rescue => e
    log_exception(e, sql)
    raise
  ensure
    log_duration(Time.now - start, sql) unless e
  end
end
log_exception (exception, message)

Log a message at error level, with information about the exception.

[show source]
# File lib/sequel/database/logging.rb, line 25
def log_exception(exception, message)
  log_each(:error, "#{exception.class}: #{exception.message.strip if exception.message}: #{message}")
end
log_info (message, args=nil)

Log a message at level info to all loggers.

[show source]
# File lib/sequel/database/logging.rb, line 30
def log_info(message, args=nil)
  log_each(:info, args ? "#{message}; #{args.inspect}" : message)
end
logger= (logger)

Remove any existing loggers and just use the given logger:

DB.logger = Logger.new($stdout)
[show source]
# File lib/sequel/database/logging.rb, line 53
def logger=(logger)
  @loggers = Array(logger)
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 Sequel doesn't have specific support for the database in use.

DEFAULT_STRING_COLUMN_SIZE = 255  

The general default size for string columns for all Sequel::Database instances.

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).

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

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.

Public Class methods

after_initialize (&block)

Register a hook that will be run when a new Database is instantiated. It is called with the new database handle.

[show source]
# File lib/sequel/database/misc.rb, line 33
def self.after_initialize(&block)
  raise Error, "must provide block to after_initialize" unless block
  Sequel.synchronize do
    previous = @initialize_hook
    @initialize_hook = Proc.new do |db|
      previous.call(db)
      block.call(db)
    end
  end
end
extension (*extensions)

Apply an extension to all Database objects created in the future.

[show source]
# File lib/sequel/database/misc.rb, line 45
def self.extension(*extensions)
  after_initialize{|db| db.extension(*extensions)}
end
new (opts = OPTS)

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.

[show source]
# File lib/sequel/database/misc.rb, line 113
def initialize(opts = OPTS)
  @opts ||= opts
  @opts = connection_pool_default_options.merge(@opts)
  @loggers = Array(@opts[:logger]) + Array(@opts[:loggers])
  @opts[:servers] = {} if @opts[:servers].is_a?(String)
  @sharded = !!@opts[:servers]
  @opts[:adapter_class] = self.class
  @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, Sequel.single_threaded))
  @default_string_column_size = @opts[:default_string_column_size] || DEFAULT_STRING_COLUMN_SIZE

  @schemas = {}
  @prepared_statements = {}
  @transactions = {}
  @symbol_literal_cache = {}

  @timezone = nil

  @dataset_class = dataset_class_default
  @cache_schema = typecast_value_boolean(@opts.fetch(:cache_schema, true))
  @dataset_modules = []
  @loaded_extensions = []
  @schema_type_classes = SCHEMA_TYPE_CLASSES.dup

  self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info
  self.log_warn_duration = @opts[:log_warn_duration]
  self.log_connection_info = typecast_value_boolean(@opts[:log_connection_info])

  @pool = ConnectionPool.get_pool(self, @opts)

  reset_default_dataset
  adapter_initialize

  unless typecast_value_boolean(@opts[:keep_reference]) == false
    Sequel.synchronize{::Sequel::DATABASES.push(self)}
  end
  Sequel::Database.run_after_initialize(self)
  if typecast_value_boolean(@opts[:preconnect]) && @pool.respond_to?(:preconnect, true)
    concurrent = typecast_value_string(@opts[:preconnect]) == "concurrently"
    @pool.send(:preconnect, concurrent)
  end

  case exts = @opts[:extensions]
  when String
    extension(*exts.split(',').map(&:to_sym))
  when Array
    extension(*exts)
  when Symbol
    extension(exts)
  when nil
    # nothing
  else
    raise Error, "unsupported Database :extensions option: #{@opts[:extensions].inspect}"
  end
end
register_extension (ext, mod=nil, &block)

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.

[show source]
# File lib/sequel/database/misc.rb, line 54
def self.register_extension(ext, mod=nil, &block)
  if mod
    raise(Error, "cannot provide both mod and block to Database.register_extension") if block
    if mod.is_a?(Module)
      block = proc{|db| db.extend(mod)}
    else
      block = mod
    end
  end
  Sequel.synchronize{EXTENSIONS[ext] = block}
end
run_after_initialize (instance)

Run the ::after_initialize hook for the given instance.

[show source]
# File lib/sequel/database/misc.rb, line 67
def self.run_after_initialize(instance)
  @initialize_hook.call(instance)
end

Public Instance methods

cast_type_literal (type)

Cast the given type to a literal type

DB.cast_type_literal(Float) # double precision
DB.cast_type_literal(:foo)  # foo
[show source]
# File lib/sequel/database/misc.rb, line 193
def cast_type_literal(type)
  type_literal(:type=>type)
end
extension (*exts)

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.

[show source]
# File lib/sequel/database/misc.rb, line 202
def extension(*exts)
  Sequel.extension(*exts)
  exts.each do |ext|
    if pr = Sequel.synchronize{EXTENSIONS[ext]}
      unless Sequel.synchronize{@loaded_extensions.include?(ext)}
        Sequel.synchronize{@loaded_extensions << ext}
        pr.call(self)
      end
    else
      raise(Error, "Extension #{ext} does not have specific support handling individual databases (try: Sequel.extension #{ext.inspect})")
    end
  end
  self
end
freeze ()

Freeze internal data structures for the Database instance.

[show source]
# File lib/sequel/database/misc.rb, line 169
def freeze
  valid_connection_sql
  metadata_dataset
  @opts.freeze
  @loggers.freeze
  @pool.freeze
  @dataset_class.freeze
  @dataset_modules.freeze
  @schema_type_classes.freeze
  @loaded_extensions.freeze
  metadata_dataset
  super
end
from_application_timestamp (v)

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.

[show source]
# File lib/sequel/database/misc.rb, line 220
def from_application_timestamp(v)
  Sequel.convert_output_timestamp(v, timezone)
end
inspect ()

Returns a string representation of the database object including the class name and connection URI and options used when connecting (if any).

[show source]
# File lib/sequel/database/misc.rb, line 226
def inspect
  a = []
  a << uri.inspect if uri
  if (oo = opts[:orig_opts]) && !oo.empty?
    a << oo.inspect
  end
  "#<#{self.class}: #{a.join(' ')}>"
end
literal (v)

Proxy the literal call to the dataset.

DB.literal(1)   # 1
DB.literal(:a)  # a
DB.literal('a') # 'a'
[show source]
# File lib/sequel/database/misc.rb, line 240
def literal(v)
  schema_utility_dataset.literal(v)
end
literal_symbol (sym)

Return the literalized version of the symbol if cached, or nil if it is not cached.

[show source]
# File lib/sequel/database/misc.rb, line 246
def literal_symbol(sym)
  Sequel.synchronize{@symbol_literal_cache[sym]}
end
literal_symbol_set (sym, lit)

Set the cached value of the literal symbol.

[show source]
# File lib/sequel/database/misc.rb, line 251
def literal_symbol_set(sym, lit)
  Sequel.synchronize{@symbol_literal_cache[sym] = lit}
end
prepared_statement (name)

Synchronize access to the prepared statements cache.

[show source]
# File lib/sequel/database/misc.rb, line 256
def prepared_statement(name)
  Sequel.synchronize{prepared_statements[name]}
end
quote_identifier (v)

Proxy the #quote_identifier method to the dataset, useful for quoting unqualified identifiers for use outside of datasets.

[show source]
# File lib/sequel/database/misc.rb, line 263
def quote_identifier(v)
  schema_utility_dataset.quote_identifier(v)
end
schema_type_class (type)

Return ruby class or array of classes for the given type symbol.

[show source]
# File lib/sequel/database/misc.rb, line 268
def schema_type_class(type)
  @schema_type_classes[type]
end
serial_primary_key_options ()

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

[show source]
# File lib/sequel/database/misc.rb, line 273
def serial_primary_key_options
  {:primary_key => true, :type => Integer, :auto_increment => true}
end
set_prepared_statement (name, ps)

Cache the prepared statement object at the given name.

[show source]
# File lib/sequel/database/misc.rb, line 278
def set_prepared_statement(name, ps)
  Sequel.synchronize{prepared_statements[name] = ps}
end
sharded? ()

Whether this database instance uses multiple servers, either for sharding or for master/slave.

[show source]
# File lib/sequel/database/misc.rb, line 284
def sharded?
  @sharded
end
timezone ()

The timezone to use for this database, defaulting to Sequel.database_timezone.

[show source]
# File lib/sequel/database/misc.rb, line 289
def timezone
  @timezone || Sequel.database_timezone
end
to_application_timestamp (v)

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.

[show source]
# File lib/sequel/database/misc.rb, line 296
def to_application_timestamp(v)
  Sequel.convert_timestamp(v, timezone)
end
typecast_value (column_type, value)

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.

[show source]
# File lib/sequel/database/misc.rb, line 305
def typecast_value(column_type, value)
  return nil if value.nil?
  meth = "typecast_value_#{column_type}"
  begin
    # Allow calling private methods as per-type typecasting methods are private
    respond_to?(meth, true) ? send(meth, value) : value
  rescue ArgumentError, TypeError => e
    raise Sequel.convert_exception_class(e, InvalidValue)
  end
end
uri ()

Returns the URI use to connect to the database. If a URI was not used when connecting, returns nil.

[show source]
# File lib/sequel/database/misc.rb, line 318
def uri
  opts[:uri]
end
url ()

Explicit alias of uri for easier subclassing.

[show source]
# File lib/sequel/database/misc.rb, line 323
def url
  uri
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 #transaction, as on MSSQL if affects all future transactions on the same connection.

Public Instance methods

after_commit (opts=OPTS, &block)

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.

[show source]
# File lib/sequel/database/transactions.rb, line 28
def after_commit(opts=OPTS, &block)
  raise Error, "must provide block to after_commit" unless block
  synchronize(opts[:server]) do |conn|
    if h = _trans(conn)
      raise Error, "cannot call after_commit in a prepared transaction" if h[:prepare]
      add_transaction_hook(conn, :after_commit, block)
    else
      yield
    end
  end
end
after_rollback (opts=OPTS, &block)

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.

[show source]
# File lib/sequel/database/transactions.rb, line 45
def after_rollback(opts=OPTS, &block)
  raise Error, "must provide block to after_rollback" unless block
  synchronize(opts[:server]) do |conn|
    if h = _trans(conn)
      raise Error, "cannot call after_rollback in a prepared transaction" if h[:prepare]
      add_transaction_hook(conn, :after_rollback, block)
    end
  end
end
in_transaction? (opts=OPTS)

Return true if already in a transaction given the options, false otherwise. Respects the :server option for selecting a shard.

[show source]
# File lib/sequel/database/transactions.rb, line 58
def in_transaction?(opts=OPTS)
  synchronize(opts[:server]){|conn| !!_trans(conn)}
end
rollback_checker (opts=OPTS)

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.

[show source]
# File lib/sequel/database/transactions.rb, line 68
def rollback_checker(opts=OPTS)
  synchronize(opts[:server]) do |conn|
    raise Error, "not in a transaction" unless t = _trans(conn)
    t[:rollback_checker] ||= proc{Sequel.synchronize{t[:rolled_back]}}
  end
end
transaction (opts=OPTS, &block)

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 #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+).

[show source]
# File lib/sequel/database/transactions.rb, line 122
def transaction(opts=OPTS, &block)
  opts = Hash[opts]
  if retry_on = opts[:retry_on]
    tot_retries = opts.fetch(:num_retries, 5)
    num_retries = 0 unless tot_retries.nil?
    begin
      opts[:retry_on] = nil
      opts[:retrying] = true
      transaction(opts, &block)
    rescue *retry_on => e
      if num_retries
        num_retries += 1
        if num_retries <= tot_retries
          opts[:before_retry].call(num_retries, e) if opts[:before_retry]
          retry
        end
      else
        retry
      end
      raise
    end
  else
    synchronize(opts[:server]) do |conn|
      if opts[:savepoint] == :only
        if supports_savepoints?
          if _trans(conn)
            opts[:savepoint] = true
          else
            return yield(conn)
          end
        else
          opts[:savepoint] = false
        end
      end

      if already_in_transaction?(conn, opts)
        if opts[:rollback] == :always && !opts.has_key?(:savepoint)
          if supports_savepoints? 
            opts[:savepoint] = true
          else
            raise Sequel::Error, "cannot set :rollback=>:always transaction option if already inside a transaction"
          end
        end

        if opts[:savepoint] != false && (stack = _trans(conn)[:savepoints]) && stack.last
          opts[:savepoint] = true
        end

        unless opts[:savepoint]
          if opts[:retrying]
            raise Sequel::Error, "cannot set :retry_on options if you are already inside a transaction"
          end
          return yield(conn)
        end
      end

      _transaction(conn, opts, &block)
    end
  end
end

9 - Methods that describe what the database supports

Public Instance methods

global_index_namespace? ()

Whether the database uses a global namespace for the index, true by default. If false, the indexes are going to be namespaced per table.

[show source]
# File lib/sequel/database/features.rb, line 12
def global_index_namespace?
  true
end
supports_create_table_if_not_exists? ()

Whether the database supports CREATE TABLE IF NOT EXISTS syntax, false by default.

[show source]
# File lib/sequel/database/features.rb, line 18
def supports_create_table_if_not_exists?
  false
end
supports_deferrable_constraints? ()

Whether the database supports deferrable constraints, false by default as few databases do.

[show source]
# File lib/sequel/database/features.rb, line 24
def supports_deferrable_constraints?
  false
end
supports_deferrable_foreign_key_constraints? ()

Whether the database supports deferrable foreign key constraints, false by default as few databases do.

[show source]
# File lib/sequel/database/features.rb, line 30
def supports_deferrable_foreign_key_constraints?
  supports_deferrable_constraints?
end
supports_drop_table_if_exists? ()

Whether the database supports DROP TABLE IF EXISTS syntax, false by default.

[show source]
# File lib/sequel/database/features.rb, line 36
def supports_drop_table_if_exists?
  supports_create_table_if_not_exists?
end
supports_foreign_key_parsing? ()

Whether the database supports Database#foreign_key_list for parsing foreign keys.

[show source]
# File lib/sequel/database/features.rb, line 42
def supports_foreign_key_parsing?
  respond_to?(:foreign_key_list)
end
supports_index_parsing? ()

Whether the database supports Database#indexes for parsing indexes.

[show source]
# File lib/sequel/database/features.rb, line 47
def supports_index_parsing?
  respond_to?(:indexes)
end
supports_partial_indexes? ()

Whether the database supports partial indexes (indexes on a subset of a table), false by default.

[show source]
# File lib/sequel/database/features.rb, line 53
def supports_partial_indexes?
  false
end
supports_prepared_transactions? ()

Whether the database and adapter support prepared transactions (two-phase commit), false by default.

[show source]
# File lib/sequel/database/features.rb, line 59
def supports_prepared_transactions?
  false
end
supports_savepoints? ()

Whether the database and adapter support savepoints, false by default.

[show source]
# File lib/sequel/database/features.rb, line 64
def supports_savepoints?
  false
end
supports_savepoints_in_prepared_transactions? ()

Whether the database and adapter support savepoints inside prepared transactions (two-phase commit), false by default.

[show source]
# File lib/sequel/database/features.rb, line 70
def supports_savepoints_in_prepared_transactions?
  supports_prepared_transactions? && supports_savepoints?
end
supports_schema_parsing? ()

Whether the database supports schema parsing via #schema.

[show source]
# File lib/sequel/database/features.rb, line 75
def supports_schema_parsing?
  respond_to?(:schema_parse_table, true)
end
supports_table_listing? ()

Whether the database supports Database#tables for getting list of tables.

[show source]
# File lib/sequel/database/features.rb, line 80
def supports_table_listing?
  respond_to?(:tables)
end
supports_transaction_isolation_levels? ()

Whether the database and adapter support transaction isolation levels, false by default.

[show source]
# File lib/sequel/database/features.rb, line 90
def supports_transaction_isolation_levels?
  false
end
supports_transactional_ddl? ()

Whether DDL statements work correctly in transactions, false by default.

[show source]
# File lib/sequel/database/features.rb, line 95
def supports_transactional_ddl?
  false
end
supports_view_listing? ()

Whether the database supports Database#views for getting list of views.

[show source]
# File lib/sequel/database/features.rb, line 85
def supports_view_listing?
  respond_to?(:views)
end
supports_views_with_check_option? ()

Whether CREATE VIEW … WITH CHECK OPTION is supported, false by default.

[show source]
# File lib/sequel/database/features.rb, line 100
def supports_views_with_check_option?
  !!view_with_check_option_support
end
supports_views_with_local_check_option? ()

Whether CREATE VIEW … WITH LOCAL CHECK OPTION is supported, false by default.

[show source]
# File lib/sequel/database/features.rb, line 105
def supports_views_with_local_check_option?
  view_with_check_option_support == :local
end