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Sequel::Database

A Database object represents a virtual connection to a database. The Database class is meant to be subclassed by database adapters in order to provide the functionality needed for executing queries.

1 - Methods that execute queries and/or return results ↑ top

This methods generally execute SQL code on the database server.

Attributes

prepared_statements[R]

The prepared statement object hash for this database, keyed by name symbol

transaction_isolation_level[RW]

The default transaction isolation level for this database, used for all future transactions. For MSSQL, this should be set to something if you ever plan to use the :isolation option to Database#transaction, as on MSSQL if affects all future transactions on the same connection.

Public Instance Methods

<<(sql) click to toggle source

Runs the supplied SQL statement string on the database server. Returns self so it can be safely chained:

DB << "UPADTE albums SET artist_id = NULL" << "DROP TABLE artists"
# File lib/sequel/database/query.rb, line 43
def <<(sql)
  run(sql)
  self
end
call(ps_name, hash={}) click to toggle source

Call the prepared statement with the given name with the given hash of arguments.

DB[:items].filter(:id=>1).prepare(:first, :sa)
DB.call(:sa) # SELECT * FROM items WHERE id = 1
# File lib/sequel/database/query.rb, line 53
def call(ps_name, hash={})
  prepared_statements[ps_name].call(hash)
end
dump_indexes_migration(options={}) click to toggle source

Dump indexes for all tables as a migration. This complements the :indexes=>false option to dump_schema_migration. Options:

  • :same_db - Create a dump for the same database type, so don't ignore errors if the index statements fail.

# File lib/sequel/extensions/schema_dumper.rb, line 13
def dump_indexes_migration(options={})
  ts = tables(options)
  Sequel.migration do  up do#{ts.sort_by{|t| t.to_s}.map{|t| dump_table_indexes(t, :add_index, options)}.reject{|x| x == ''}.join("\n\n").gsub(/^/o, '    ')}  end    down do#{ts.sort_by{|t| t.to_s}.map{|t| dump_table_indexes(t, :drop_index, options)}.reject{|x| x == ''}.join("\n\n").gsub(/^/o, '    ')}  endend
end
dump_schema_migration(options={}) click to toggle source

Return a string that contains a Sequel::Migration subclass that when run would recreate the database structure. Options:

  • :same_db - Don't attempt to translate database types to ruby types. If this isn't set to true, all database types will be translated to ruby types, but there is no guarantee that the migration generated will yield the same type. Without this set, types that aren't recognized will be translated to a string-like type.

  • :indexes - If set to false, don't dump indexes (they can be added later via dump_index_migration).

# File lib/sequel/extensions/schema_dumper.rb, line 37
def dump_schema_migration(options={})
  ts = tables(options)
  Sequel.migration do  up do#{ts.sort_by{|t| t.to_s}.map{|t| dump_table_schema(t, options)}.join("\n\n").gsub(/^/o, '    ')}  end    down do    drop_table(#{ts.sort_by{|t| t.to_s}.inspect[1...-1]})  endend
end
dump_table_schema(table, options={}) click to toggle source

Return a string with a create table block that will recreate the given table's schema. Takes the same options as dump_schema_migration.

# File lib/sequel/extensions/schema_dumper.rb, line 54
def dump_table_schema(table, options={})
  table = table.value.to_s if table.is_a?(SQL::Identifier)
  raise(Error, "must provide table as a Symbol, String, or Sequel::SQL::Identifier") unless [String, Symbol].any?{|c| table.is_a?(c)}
  s = schema(table).dup
  pks = s.find_all{|x| x.last[:primary_key] == true}.map{|x| x.first}
  options = options.merge(:single_pk=>true) if pks.length == 1
  m = method(:column_schema_to_generator_opts)
  im = method(:index_to_generator_opts)
  begin
    indexes = indexes(table).sort_by{|k,v| k.to_s} if options[:indexes] != false
  rescue Sequel::NotImplemented
    nil
  end
  gen = Schema::Generator.new(self) do
    s.each{|name, info| send(*m.call(name, info, options))}
    primary_key(pks) if !@primary_key && pks.length > 0
    indexes.each{|iname, iopts| send(:index, iopts[:columns], im.call(table, iname, iopts))} if indexes
  end
  commands = [gen.dump_columns, gen.dump_constraints, gen.dump_indexes].reject{|x| x == ''}.join("\n\n")
  "create_table(#{table.inspect}#{', :ignore_index_errors=>true' if !options[:same_db] && options[:indexes] != false && indexes && !indexes.empty?}) do\n#{commands.gsub(/^/o, '  ')}\nend"
end
execute(sql, opts={}) click to toggle source

Executes the given SQL on the database. This method should be overridden in descendants. This method should not be called directly by user code.

# File lib/sequel/database/query.rb, line 59
def execute(sql, opts={})
  raise NotImplemented, "#execute should be overridden by adapters"
end
execute_ddl(sql, opts={}, &block) click to toggle source

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 66
def execute_ddl(sql, opts={}, &block)
  execute_dui(sql, opts, &block)
end
execute_dui(sql, opts={}, &block) click to toggle source

Method that should be used when issuing a DELETE, UPDATE, or INSERT statement. By default, calls execute. This method should not be called directly by user code.

# File lib/sequel/database/query.rb, line 73
def execute_dui(sql, opts={}, &block)
  execute(sql, opts, &block)
end
execute_insert(sql, opts={}, &block) click to toggle source

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 80
def execute_insert(sql, opts={}, &block)
  execute_dui(sql, opts, &block)
end
get(*args, &block) click to toggle source

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

DB.get(1) # SELECT 1
# => 1
DB.get{server_version{}} # SELECT server_version()
# File lib/sequel/database/query.rb, line 89
def get(*args, &block)
  dataset.get(*args, &block)
end
indexes(table, opts={}) click to toggle source

Return a hash containing index information for the table. Hash keys are index name symbols. Values are subhashes with two keys, :columns and :unique. The value of :columns is an array of symbols of column names. The value of :unique is true or false depending on if the index is unique.

Should not include the primary key index, functional indexes, or partial indexes.

DB.indexes(:artists)
# => {:artists_name_ukey=>{:columns=>[:name], :unique=>true}}
# File lib/sequel/database/query.rb, line 102
def indexes(table, opts={})
  raise NotImplemented, "#indexes should be overridden by adapters"
end
query(&block) click to toggle source

Return a dataset modified by the query block

# File lib/sequel/extensions/query.rb, line 8
def query(&block)
  dataset.query(&block)
end
run(sql, opts={}) click to toggle source

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 111
def run(sql, opts={})
  execute_ddl(sql, opts)
  nil
end
schema(table, opts={}) click to toggle source

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 should hash at least contain 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.

: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 156
def schema(table, opts={})
  raise(Error, 'schema parsing is not implemented on this database') unless respond_to?(:schema_parse_table, true)

  opts = opts.dup
  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)
    tab = table.first_source_table
    sch, table_name = schema_and_table(tab)
    quoted_name = table.literal(tab)
    opts[:dataset] = table
  else
    sch, table_name = schema_and_table(table)
    quoted_name = quote_schema_table(table)
  end
  opts[:schema] = sch if sch && !opts.include?(:schema)

  @schemas.delete(quoted_name) if opts[:reload]
  return @schemas[quoted_name] if @schemas[quoted_name]

  cols = schema_parse_table(table_name, opts)
  raise(Error, 'schema parsing returned no columns, table probably doesn\t exist') if cols.nil? || cols.empty?
  cols.each{|_,c| c[:ruby_default] = column_schema_to_ruby_default(c[:default], c[:type])}
  @schemas[quoted_name] = cols
end
table_exists?(name) click to toggle source

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

DB.table_exists?(:foo) # => false
# SELECT * FROM foo LIMIT 1
# File lib/sequel/database/query.rb, line 188
def table_exists?(name)
  sch, table_name = schema_and_table(name)
  name = SQL::QualifiedIdentifier.new(sch, table_name) if sch
  from(name).first
  true
rescue
  false
end
tables(opts={}) click to toggle source

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

DB.tables # => [:albums, :artists]
# File lib/sequel/database/query.rb, line 200
def tables(opts={})
  raise NotImplemented, "#tables should be overridden by adapters"
end
transaction(opts={}, &block) click to toggle source

Starts a database transaction. When a database transaction is used, either all statements are successful or none of the statements are successful. Note that MySQL MyISAM tabels do not support transactions.

The following options are respected:

:isolation

The transaction isolation level to use for this transaction, should be :uncommitted, :committed, :repeatable, or :serializable, used if given and the database/adapter supports customizable transaction isolation levels.

:prepare

A string to use as the transaction identifier for a prepared transaction (two-phase commit), if the database/adapter supports prepared transactions.

: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.

:savepoint

Whether to create a new savepoint for this transaction, only respected if the database/adapter supports savepoints. By default Sequel will reuse an existing transaction, so if you want to use a savepoint you must use this option.

# File lib/sequel/database/query.rb, line 225
def transaction(opts={}, &block)
  synchronize(opts[:server]) do |conn|
    return yield(conn) if already_in_transaction?(conn, opts)
    _transaction(conn, opts, &block)
  end
end
views(opts={}) click to toggle source

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

DB.views # => [:gold_albums, :artists_with_many_albums]
# File lib/sequel/database/query.rb, line 235
def views(opts={})
  raise NotImplemented, "#views should be overridden by adapters"
end

2 - Methods that modify the database schema ↑ top

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

Public Instance Methods

add_column(table, *args) click to toggle source

Adds a column to the specified table. This method expects a column name, a datatype and optionally a hash with additional constraints and options:

DB.add_column :items, :name, :text, :unique => true, :null => false
DB.add_column :items, :category, :text, :default => 'ruby'

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 33
def add_column(table, *args)
  alter_table(table) {add_column(*args)}
end
add_index(table, columns, options={}) click to toggle source

Adds an index to a table for the given columns:

DB.add_index :posts, :title
DB.add_index :posts, [:author, :title], :unique => true

Options:

:ignore_errors

Ignore any DatabaseErrors that are raised

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 46
def add_index(table, columns, options={})
  e = options[:ignore_errors]
  begin
    alter_table(table){add_index(columns, options)}
  rescue DatabaseError
    raise unless e
  end
end
alter_table(name, generator=nil, &block) click to toggle source

Alters the given table with the specified block. Example:

DB.alter_table :items do
  add_column :category, :text, :default => 'ruby'
  drop_column :category
  rename_column :cntr, :counter
  set_column_type :value, :float
  set_column_default :value, :float
  add_index [:group, :category]
  drop_index [:group, :category]
end

Note that add_column accepts all the options available for column definitions using create_table, and add_index accepts all the options available for index definition.

See Schema::AlterTableGenerator and the "Migrations and Schema Modification" guide.

# File lib/sequel/database/schema_methods.rb, line 72
def alter_table(name, generator=nil, &block)
  generator ||= Schema::AlterTableGenerator.new(self, &block)
  remove_cached_schema(name)
  apply_alter_table(name, generator.operations)
  nil
end
create_or_replace_view(name, source) click to toggle source

Creates a view, replacing it if it already exists:

DB.create_or_replace_view(:cheap_items, "SELECT * FROM items WHERE price < 100")
DB.create_or_replace_view(:ruby_items, DB[:items].filter(:category => 'ruby'))
# File lib/sequel/database/schema_methods.rb, line 130
def create_or_replace_view(name, source)
  source = source.sql if source.is_a?(Dataset)
  execute_ddl("CREATE OR REPLACE VIEW #{quote_schema_table(name)} AS #{source}")
  remove_cached_schema(name)
  nil
end
create_table(name, options={}, &block) click to toggle source

Creates a table with the columns given in the provided block:

DB.create_table :posts do
  primary_key :id
  column :title, :text
  String :content
  index :title
end

Options:

:temp

Create the table as a temporary table.

:ignore_index_errors

Ignore any errors when creating indexes.

See Schema::Generator and the "Migrations and Schema Modification" guide.

# File lib/sequel/database/schema_methods.rb, line 93
def create_table(name, options={}, &block)
  remove_cached_schema(name)
  options = {:generator=>options} if options.is_a?(Schema::Generator)
  generator = options[:generator] || Schema::Generator.new(self, &block)
  create_table_from_generator(name, generator, options)
  create_table_indexes_from_generator(name, generator, options)
  nil
end
create_table!(name, options={}, &block) click to toggle source

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

DB.create_table!(:a){Integer :a} 
# SELECT * FROM a LIMIT a -- check existence
# DROP TABLE a -- drop table if already exists
# CREATE TABLE a (a integer)
# File lib/sequel/database/schema_methods.rb, line 108
def create_table!(name, options={}, &block)
  drop_table(name) if table_exists?(name)
  create_table(name, options, &block)
end
create_table?(name, options={}, &block) click to toggle source

Creates the table unless the table already exists.

DB.create_table?(:a){Integer :a} 
# SELECT * FROM a LIMIT a -- check existence
# CREATE TABLE a (a integer) -- if it doesn't already exist
# File lib/sequel/database/schema_methods.rb, line 118
def create_table?(name, options={}, &block)
  if supports_create_table_if_not_exists?
    create_table(name, options.merge(:if_not_exists=>true), &block)
  elsif !table_exists?(name)
    create_table(name, options, &block)
  end
end
create_view(name, source) click to toggle source

Creates a view based on a dataset or an SQL string:

DB.create_view(:cheap_items, "SELECT * FROM items WHERE price < 100")
DB.create_view(:ruby_items, DB[:items].filter(:category => 'ruby'))
# File lib/sequel/database/schema_methods.rb, line 141
def create_view(name, source)
  source = source.sql if source.is_a?(Dataset)
  execute_ddl("CREATE VIEW #{quote_schema_table(name)} AS #{source}")
end
drop_column(table, *args) click to toggle source

Removes a column from the specified table:

DB.drop_column :items, :category

See alter_table.

# File lib/sequel/database/schema_methods.rb, line 151
def drop_column(table, *args)
  alter_table(table) {drop_column(*args)}
end
drop_index(table, columns, options={}) click to toggle source

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 161
def drop_index(table, columns, options={})
  alter_table(table){drop_index(columns, options)}
end
drop_table(*names) click to toggle source

Drops one or more tables corresponding to the given names:

DB.drop_table(:posts)
DB.drop_table(:posts, :comments)
DB.drop_table(:posts, :comments, :cascade=>true)
# File lib/sequel/database/schema_methods.rb, line 170
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_view(*names) click to toggle source

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)
# File lib/sequel/database/schema_methods.rb, line 184
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) click to toggle source

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 210
def rename_column(table, *args)
  alter_table(table) {rename_column(*args)}
end
rename_table(name, new_name) click to toggle source

Renames a table:

DB.tables #=> [:items]
DB.rename_table :items, :old_items
DB.tables #=> [:old_items]
# File lib/sequel/database/schema_methods.rb, line 198
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) click to toggle source

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 219
def set_column_default(table, *args)
  alter_table(table) {set_column_default(*args)}
end
set_column_type(table, *args) click to toggle source

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 228
def set_column_type(table, *args)
  alter_table(table) {set_column_type(*args)}
end

3 - Methods that create datasets ↑ top

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

Public Instance Methods

[](*args) click to toggle source

Returns a dataset for the database. If the first argument is a string, the method acts as an alias for Database#fetch, returning a dataset for arbitrary SQL, with or without placeholders:

DB['SELECT * FROM items'].all
DB['SELECT * FROM items WHERE name = ?', my_name].all

Otherwise, acts as an alias for Database#from, setting the primary table for the dataset:

DB[:items].sql #=> "SELECT * FROM items"
# File lib/sequel/database/dataset.rb, line 19
def [](*args)
  (String === args.first) ? fetch(*args) : from(*args)
end
dataset(opts=nil) click to toggle source

Returns a blank dataset for this database.

DB.dataset # SELECT *
DB.dataset.from(:items) # SELECT * FROM items
# File lib/sequel/database/dataset.rb, line 27
def dataset(opts=nil)
  @dataset_class.new(self, opts)
end
fetch(sql, *args, &block) click to toggle source

Fetches records for an arbitrary SQL statement. If a block is given, it is used to iterate over the records:

DB.fetch('SELECT * FROM items'){|r| p r}

The fetch method returns a dataset instance:

DB.fetch('SELECT * FROM items').all

fetch can also perform parameterized queries for protection against SQL injection:

DB.fetch('SELECT * FROM items WHERE name = ?', my_name).all
# File lib/sequel/database/dataset.rb, line 44
def fetch(sql, *args, &block)
  ds = dataset.with_sql(sql, *args)
  ds.each(&block) if block
  ds
end
from(*args, &block) click to toggle source

Returns a new dataset with the from method invoked. If a block is given, it is used as a filter on the dataset.

DB.from(:items) # SELECT * FROM items
DB.from(:items){id > 2} # SELECT * FROM items WHERE (id > 2)
# File lib/sequel/database/dataset.rb, line 55
def from(*args, &block)
  ds = dataset.from(*args)
  block ? ds.filter(&block) : ds
end
select(*args, &block) click to toggle source

Returns a new dataset with the select method invoked.

DB.select(1) # SELECT 1
DB.select{server_version{}} # SELECT server_version()
DB.select(:id).from(:items) # SELECT id FROM items
# File lib/sequel/database/dataset.rb, line 65
def select(*args, &block)
  dataset.select(*args, &block)
end

4 - Methods relating to adapters, connecting, disconnecting, and sharding ↑ top

This methods involve the Database's connection pool.

Constants

ADAPTERS

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) click to toggle source

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

# File lib/sequel/database/connecting.rb, line 17
def self.adapter_class(scheme)
  return scheme if scheme.is_a?(Class)

  scheme = scheme.to_s.gsub('-', '_').to_sym
  
  unless klass = ADAPTER_MAP[scheme]
    # attempt to load the adapter file
    begin
      Sequel.tsk_require "sequel/adapters/#{scheme}"
    rescue LoadError => e
      raise Sequel.convert_exception_class(e, AdapterNotFound)
    end
    
    # make sure we actually loaded the adapter
    unless klass = ADAPTER_MAP[scheme]
      raise AdapterNotFound, "Could not load #{scheme} adapter: adapter class not registered in ADAPTER_MAP"
    end
  end
  klass
end
adapter_scheme() click to toggle source

Returns the scheme symbol for the Database class.

# File lib/sequel/database/connecting.rb, line 39
def self.adapter_scheme
  @scheme
end
connect(conn_string, opts = {}) click to toggle source

Connects to a database. See Sequel.connect.

# File lib/sequel/database/connecting.rb, line 44
def self.connect(conn_string, opts = {})
  case conn_string
  when String
    if match = /\A(jdbc|do):/.match(conn_string)
      c = adapter_class(match[1].to_sym)
      opts = {:uri=>conn_string}.merge(opts)
    else
      uri = URI.parse(conn_string)
      scheme = uri.scheme
      scheme = :dbi if scheme =~ /\Adbi-/
      c = adapter_class(scheme)
      uri_options = c.send(:uri_to_options, uri)
      uri.query.split('&').collect{|s| s.split('=')}.each{|k,v| uri_options[k.to_sym] = v if k && !k.empty?} unless uri.query.to_s.strip.empty?
      uri_options.to_a.each{|k,v| uri_options[k] = URI.unescape(v) if v.is_a?(String)}
      opts = uri_options.merge(opts)
      opts[:adapter] = scheme
    end
  when Hash
    opts = conn_string.merge(opts)
    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
  # process opts a bit
  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 opts[:test] && db.send(:typecast_value_boolean, opts[:test])
    result = yield(db) if block_given?
  ensure
    if block_given?
      db.disconnect if db
      ::Sequel::DATABASES.delete(db)
    end
  end
  block_given? ? result : db
end
single_threaded=(value) click to toggle source

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

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

Public Instance Methods

adapter_scheme() click to toggle source

Returns the scheme symbol for this instance's class, which reflects which adapter is being used. In some cases, this can be the same as the database_type (for native adapters), in others (i.e. adapters with subadapters), it will be different.

Sequel.connect('jdbc:postgres://...').adapter_scheme # => :jdbc
# File lib/sequel/database/connecting.rb, line 120
def adapter_scheme
  self.class.adapter_scheme
end
add_servers(servers) click to toggle source

Dynamically add new servers or modify server options at runtime. Also adds new servers to the connection pool. Intended for use with master/slave or shard configurations where it is useful to add new server hosts at runtime.

servers argument should be a hash with server name symbol keys and hash or proc values. If a servers key is already in use, it's value is overridden with the value provided.

DB.add_servers(:f=>{:host=>"hash_host_f"})
# File lib/sequel/database/connecting.rb, line 133
def add_servers(servers)
  @opts[:servers] = @opts[:servers] ? @opts[:servers].merge(servers) : servers
  @pool.add_servers(servers.keys)
end
connect(server) click to toggle source

Connects to the database. This method should be overridden by descendants.

# File lib/sequel/database/connecting.rb, line 139
def connect(server)
  raise NotImplemented, "#connect should be overridden by adapters"
end
database_type() click to toggle source

The database type for this database object, the same as the adapter scheme by default. Should be overridden in adapters (especially shared adapters) to be the correct type, so that even if two separate Database objects are using different adapters you can tell that they are using the same database type. Even better, you can tell that two Database objects that are using the same adapter are connecting to different database types (think JDBC or DataObjects).

Sequel.connect('jdbc:postgres://...').database_type # => :postgres
# File lib/sequel/database/connecting.rb, line 152
def database_type
  adapter_scheme
end
disconnect(opts = {}) click to toggle source

Disconnects all available connections from the connection pool. Any connections currently in use will not be disconnected. Options:

:servers

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(:servers=>:server1) # Single server
DB.disconnect(:servers=>[:server1, :server2]) # Multiple servers
# File lib/sequel/database/connecting.rb, line 166
def disconnect(opts = {})
  pool.disconnect(opts)
end
each_server(&block) click to toggle source

Yield a new Database instance for every server in the connection pool. Intended for use in sharded environments where there is a need to make schema modifications (DDL queries) on each shard.

DB.each_server{|db| db.create_table(:users){primary_key :id; String :name}}
# File lib/sequel/database/connecting.rb, line 175
def each_server(&block)
  servers.each{|s| self.class.connect(server_opts(s), &block)}
end
remove_servers(*servers) click to toggle source

Dynamically remove existing servers from the connection pool. Intended for use with master/slave or shard configurations where it is useful to remove existing server hosts at runtime.

servers should be symbols or arrays of symbols. If a nonexistent server is specified, it is ignored. If no servers have been specified for this database, no changes are made. If you attempt to remove the :default server, an error will be raised.

DB.remove_servers(:f1, :f2)
# File lib/sequel/database/connecting.rb, line 189
def remove_servers(*servers)
  if @opts[:servers] && !@opts[:servers].empty?
    servs = @opts[:servers].dup
    servers.flatten!
    servers.each{|s| servs.delete(s)}
    @opts[:servers] = servs
    @pool.remove_servers(servers)
  end
end
servers() click to toggle source

An array of servers/shards for this Database object.

DB.servers # Unsharded: => [:default]
DB.servers # Sharded:   => [:default, :server1, :server2]
# File lib/sequel/database/connecting.rb, line 203
def servers
  pool.servers
end
single_threaded?() click to toggle source

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

# File lib/sequel/database/connecting.rb, line 208
def single_threaded?
  @single_threaded
end
synchronize(server=nil, &block) click to toggle source

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 224
def synchronize(server=nil, &block)
  @pool.hold(server || :default, &block)
end
test_connection(server=nil) click to toggle source

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 232
def test_connection(server=nil)
  synchronize(server){|conn|}
  true
end

5 - Methods that set defaults for created datasets ↑ top

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

Constants

DatasetClass

The default class to use for 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.

default_schema[RW]

The default schema to use, generally should be nil.

Public Class Methods

identifier_input_method() click to toggle source

The method to call on identifiers going into the database

# File lib/sequel/database/dataset_defaults.rb, line 21
def self.identifier_input_method
  @@identifier_input_method
end
identifier_input_method=(v) click to toggle source

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

# File lib/sequel/database/dataset_defaults.rb, line 27
def self.identifier_input_method=(v)
  @@identifier_input_method = v || ""
end
identifier_output_method() click to toggle source

The method to call on identifiers coming from the database

# File lib/sequel/database/dataset_defaults.rb, line 32
def self.identifier_output_method
  @@identifier_output_method
end
identifier_output_method=(v) click to toggle source

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

# File lib/sequel/database/dataset_defaults.rb, line 38
def self.identifier_output_method=(v)
  @@identifier_output_method = v || ""
end
quote_identifiers=(value) click to toggle source

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

# File lib/sequel/database/dataset_defaults.rb, line 44
def self.quote_identifiers=(value)
  @@quote_identifiers = value
end

Public Instance Methods

dataset_class=(c) click to toggle source

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 59
def dataset_class=(c)
  unless @dataset_modules.empty?
    c = Class.new(c)
    @dataset_modules.each{|m| c.send(:include, m)}
  end
  @dataset_class = c
end
extend_datasets(mod=nil, &block) click to toggle source

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.

Examples:

# Introspec 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
# File lib/sequel/database/dataset_defaults.rb, line 89
def extend_datasets(mod=nil, &block)
  raise(Error, "must provide either mod or block, not both") if mod && block
  mod = Module.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)
end
identifier_input_method() click to toggle source

The method to call on identifiers going into the database

# File lib/sequel/database/dataset_defaults.rb, line 102
def identifier_input_method
  case @identifier_input_method
  when nil
    @identifier_input_method = @opts.fetch(:identifier_input_method, (@@identifier_input_method.nil? ? identifier_input_method_default : @@identifier_input_method))
    @identifier_input_method == "" ? nil : @identifier_input_method
  when ""
    nil
  else
    @identifier_input_method
  end
end
identifier_input_method=(v) click to toggle source

Set the method to call on identifiers going into the database:

DB[:items] # SELECT * FROM items
DB.identifier_input_method = :upcase
DB[:items] # SELECT * FROM ITEMS
# File lib/sequel/database/dataset_defaults.rb, line 119
def identifier_input_method=(v)
  reset_schema_utility_dataset
  @identifier_input_method = v || ""
end
identifier_output_method() click to toggle source

The method to call on identifiers coming from the database

# File lib/sequel/database/dataset_defaults.rb, line 125
def identifier_output_method
  case @identifier_output_method
  when nil
    @identifier_output_method = @opts.fetch(:identifier_output_method, (@@identifier_output_method.nil? ? identifier_output_method_default : @@identifier_output_method))
    @identifier_output_method == "" ? nil : @identifier_output_method
  when ""
    nil
  else
    @identifier_output_method
  end
end
identifier_output_method=(v) click to toggle source

Set the method to call on identifiers coming from the database:

DB[:items].first # {:id=>1, :name=>'foo'}
DB.identifier_output_method = :upcase
DB[:items].first # {:ID=>1, :NAME=>'foo'}
# File lib/sequel/database/dataset_defaults.rb, line 142
def identifier_output_method=(v)
  reset_schema_utility_dataset
  @identifier_output_method = v || ""
end
quote_identifiers=(v) click to toggle source

Set whether to quote identifiers (columns and tables) for this database:

DB[:items] # SELECT * FROM items
DB.quote_identifiers = true
DB[:items] # SELECT * FROM "items"
# File lib/sequel/database/dataset_defaults.rb, line 152
def quote_identifiers=(v)
  reset_schema_utility_dataset
  @quote_identifiers = v
end
quote_identifiers?() click to toggle source

Returns true if the database quotes identifiers.

# File lib/sequel/database/dataset_defaults.rb, line 158
def quote_identifiers?
  return @quote_identifiers unless @quote_identifiers.nil?
  @quote_identifiers = @opts.fetch(:quote_identifiers, (@@quote_identifiers.nil? ? quote_identifiers_default : @@quote_identifiers))
end

6 - Methods relating to logging ↑ top

This methods affect relating to the logging of executed SQL.

Attributes

log_warn_duration[RW]

Numeric specifying the duration beyond which queries are logged at warn level instead of info level.

loggers[RW]

Array of SQL loggers to use for this database.

sql_log_level[RW]

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

Public Instance Methods

log_info(message, args=nil) click to toggle source

Log a message at level info to all loggers.

# File lib/sequel/database/logging.rb, line 21
def log_info(message, args=nil)
  log_each(:info, args ? "#{message}; #{args.inspect}" : message)
end
log_yield(sql, args=nil) click to toggle source

Yield to the block, logging any errors at error level to all loggers, and all other queries with the duration at warn or info level.

# File lib/sequel/database/logging.rb, line 27
def log_yield(sql, args=nil)
  return yield if @loggers.empty?
  sql = "#{sql}; #{args.inspect}" if args
  start = Time.now
  begin
    yield
  rescue => e
    log_each(:error, "#{e.class}: #{e.message.strip}: #{sql}")
    raise
  ensure
    log_duration(Time.now - start, sql) unless e
  end
end
logger=(logger) click to toggle source

Remove any existing loggers and just use the given logger:

DB.logger = Logger.new($stdout)
# File lib/sequel/database/logging.rb, line 44
def logger=(logger)
  @loggers = Array(logger)
end

7 - Miscellaneous methods ↑ top

These methods don't fit neatly into another category.

Constants

LEADING_ZERO_RE

Used for checking/removing leading zeroes from strings so they don't get interpreted as octal.

LEADING_ZERO_REP

Replacement string when replacing leading zeroes.

Attributes

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

new(opts = {}, &block) click to toggle source

Constructs a new instance of a database connection with the specified options hash.

Accepts the following options:

:default_schema

The default schema to use, should generally be nil

:disconnection_proc

A proc used to disconnect the connection

:identifier_input_method

A string method symbol to call on identifiers going into the database

:identifier_output_method

A string method symbol to call on identifiers coming from the database

:logger

A specific logger to use

:loggers

An array of loggers to use

:quote_identifiers

Whether to quote identifiers

:servers

A hash specifying a server/shard specific options, keyed by shard symbol

:single_threaded

Whether to use a single-threaded connection pool

:sql_log_level

Method to use to log SQL to a logger, :info by default.

All options given are also passed to the connection pool. If a block is given, it is used as the connection_proc for the ConnectionPool.

# File lib/sequel/database/misc.rb, line 42
def initialize(opts = {}, &block)
  @opts ||= opts
  @opts = connection_pool_default_options.merge(@opts)
  @loggers = Array(@opts[:logger]) + Array(@opts[:loggers])
  self.log_warn_duration = @opts[:log_warn_duration]
  @opts[:disconnection_proc] ||= proc{|conn| disconnect_connection(conn)}
  block ||= proc{|server| connect(server)}
  @opts[:servers] = {} if @opts[:servers].is_a?(String)
  @opts[:adapter_class] = self.class
  
  @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, @@single_threaded))
  @schemas = {}
  @default_schema = @opts.fetch(:default_schema, default_schema_default)
  @prepared_statements = {}
  @transactions = {}
  @identifier_input_method = nil
  @identifier_output_method = nil
  @quote_identifiers = nil
  @timezone = nil
  @dataset_class = dataset_class_default
  @dataset_modules = []
  self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info
  @pool = ConnectionPool.get_pool(@opts, &block)

  ::Sequel::DATABASES.push(self)
end

Public Instance Methods

after_commit(opts={}, &block) click to toggle source

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/misc.rb, line 74
def after_commit(opts={}, &block)
  raise Error, "must provide block to after_commit" unless block
  synchronize(opts[:server]) do |conn|
    if h = @transactions[conn]
      raise Error, "cannot call after_commit in a prepared transaction" if h[:prepare]
      (h[:after_commit] ||= []) << block
    else
      yield
    end
  end
end
after_rollback(opts={}, &block) click to toggle source

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/misc.rb, line 91
def after_rollback(opts={}, &block)
  raise Error, "must provide block to after_rollback" unless block
  synchronize(opts[:server]) do |conn|
    if h = @transactions[conn]
      raise Error, "cannot call after_rollback in a prepared transaction" if h[:prepare]
      (h[:after_rollback] ||= []) << block
    end
  end
end
cast_type_literal(type) click to toggle source

Cast the given type to a literal type

DB.cast_type_literal(Float) # double precision
DB.cast_type_literal(:foo) # foo
# File lib/sequel/database/misc.rb, line 105
def cast_type_literal(type)
  type_literal(:type=>type)
end
from_application_timestamp(v) click to toggle source

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 112
def from_application_timestamp(v)
  Sequel.convert_output_timestamp(v, timezone)
end
in_transaction?(opts={}) click to toggle source

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

# File lib/sequel/database/misc.rb, line 119
def in_transaction?(opts={})
  synchronize(opts[:server]){|conn| !!@transactions[conn]}
end
inspect() click to toggle source

Returns a string representation of the database object including the class name and the connection URI (or the opts if the URI cannot be constructed).

# File lib/sequel/database/misc.rb, line 126
def inspect
  "#<#{self.class}: #{(uri rescue opts).inspect}>" 
end
literal(v) click to toggle source

Proxy the literal call to the dataset.

DB.literal(1) # 1
DB.literal(:a) # a
DB.literal('a') # 'a'
# File lib/sequel/database/misc.rb, line 135
def literal(v)
  schema_utility_dataset.literal(v)
end
serial_primary_key_options() click to toggle source

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

# File lib/sequel/database/misc.rb, line 141
def serial_primary_key_options
  {:primary_key => true, :type => Integer, :auto_increment => true}
end
supports_create_table_if_not_exists?() click to toggle source

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

# File lib/sequel/database/misc.rb, line 147
def supports_create_table_if_not_exists?
  false
end
supports_prepared_transactions?() click to toggle source

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

# File lib/sequel/database/misc.rb, line 153
def supports_prepared_transactions?
  false
end
supports_savepoints?() click to toggle source

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

# File lib/sequel/database/misc.rb, line 158
def supports_savepoints?
  false
end
supports_transaction_isolation_levels?() click to toggle source

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

# File lib/sequel/database/misc.rb, line 163
def supports_transaction_isolation_levels?
  false
end
timezone() click to toggle source

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

# File lib/sequel/database/misc.rb, line 168
def timezone
  @timezone || Sequel.database_timezone
end
to_application_timestamp(v) click to toggle source

Convert the given timestamp to the application's timezone, from the databases's timezone or the default database timezone if the database does not have a timezone.

# File lib/sequel/database/misc.rb, line 175
def to_application_timestamp(v)
  Sequel.convert_timestamp(v, timezone)
end
typecast_value(column_type, value) click to toggle source

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 184
def typecast_value(column_type, value)
  return nil if value.nil?
  meth = "typecast_value_#{column_type}"
  begin
    respond_to?(meth, true) ? send(meth, value) : value
  rescue ArgumentError, TypeError => e
    raise Sequel.convert_exception_class(e, InvalidValue)
  end
end
uri() click to toggle source

Returns the URI identifying the database, which may not be the same as the URI used when connecting. This method can raise an error if the database used options instead of a connection string, and will not include uri parameters.

Sequel.connect('postgres://localhost/db?user=billg').url
# => "postgres://billg@localhost/db"
# File lib/sequel/database/misc.rb, line 202
def uri
  uri = URI::Generic.new(
    adapter_scheme.to_s,
    nil,
    @opts[:host],
    @opts[:port],
    nil,
    "/#{@opts[:database]}",
    nil,
    nil,
    nil
  )
  uri.user = @opts[:user]
  uri.password = @opts[:password] if uri.user
  uri.to_s
end
url() click to toggle source

Explicit alias of uri for easier subclassing.

# File lib/sequel/database/misc.rb, line 220
def url
  uri
end

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