ANN: Sequel 2.11.0 Released

Sequel is a lightweight database access toolkit for Ruby.

  • Sequel provides thread safety, connection pooling and a concise DSL
    for constructing database queries and table schemas.
  • Sequel also includes a lightweight but comprehensive ORM layer for
    mapping records to Ruby objects and handling associated records.
  • Sequel supports advanced database features such as prepared
    statements, bound variables, stored procedures, master/slave
    configurations, and database sharding.
  • Sequel makes it easy to deal with multiple records without having
    to break your teeth on SQL.
  • Sequel currently has adapters for ADO, DataObjects, DB2, DBI,
    Firebird, Informix, JDBC, MySQL, ODBC, OpenBase, Oracle, PostgreSQL
    and SQLite3.

Sequel 2.11.0 has been released and should be available on the gem
mirrors. The 2.11.0 release adds numerous improvements:


  • Model.[] was optimized to use static SQL in cases where doing so
    should result in the same output. This should result in a 30-40%
    performance increase. Since this can be the most significant or
    only method call in a web application action, this has potential
    to significantly enhance the performance of web application code.

    In order for this optimization to have an effect, you need to
    make sure that you are calling set_dataset with a Symbol and
    not a Dataset object:


    class Foo < Sequel::Model; end
    class Foo < Sequel::Model(:foos); end
    class Foo < Sequel::Model
    set_dataset :foos

    Not Optimized, but otherwise equivalent:

    class Foo < Sequel::Model(Model.db[:foos]); end
    class Foo < Sequel::Model
    set_dataset db[:foos]

  • Dataset#literal was refactored for performance reasons to make
    overriding it in subclasses unnecessary. The changes made result
    in a 20-25% performance increase. Sequel can spend about 10% of
    it’s time in Dataset#literal, so this may be only a 2% overall
    performance improvement.

New Features

  • Association datasets now know about the model objects that created
    them, as well as the related association reflection. This makes
    association extensions much more powerful. For example, you can
    now create generic association extensions such as:

    module FindOrCreate
    def find_or_create(vals)
    first(vals) || association_reflection.associated_class.

    The above will work for any standard one_to_many association:

    Artist.one_to_many :albums, :extend=>FindOrCreate

    Create an album named Foo related to this artist,

    unless such an album already exists


    Before, the only way to do the above was to use a closure inside
    the :dataset option proc, which couldn’t be done generically
    for multiple associations.

  • A :conditions association option was added, which allows simple
    filters to be set up without defining :graph_conditions and
    an association block:


    one_to_many(:japanese_verses, :class=>:Verse,
    :graph_conditions=>{:languageid=>3})do |ds|


    one_to_many(:japanese_verses, :class=>:Verse,

  • A :clone association option was added, which allows you to clone
    an existing association. This is most useful when you are dealing
    with a legacy schema and had to define the same options redundantly
    for each type of association. You can now do:

    many_to_many :deputies, :class=>:Employee,
    :join_table=>:employeecurrentaudits, :left_key=>:currentauditid,
    :right_key=>:employeeid, :order=>[:firstname, :lastname] do |ds|
    many_to_many :project_managers, :clone=>:deputies do |ds|
    many_to_many :team_leaders, :clone=>:deputies do |ds|

    All of the above would use the same :class, :join_table, :left_key,
    :right_key, and :order options. If you don’t provide an
    association block, but you are cloning an association that has one,
    the cloned association’s block is used. You can use the
    :block=>nil option to not use a block even if the cloned
    association has a block.

  • Dataset#select, #select_more, #order, #order_more, and #get all
    take a block that yields a Sequel::SQL::VirtualRow instance,
    similar to the behavior of filter. This allows for the easier
    use of SQL functions on Ruby 1.9:


    2.11.0{|o| o.prettify(:name)}

  • String#lit can now accept arguments and return an SQL literal
    string. This allows you to do things that were previously hard
    or at least unnecessarily verbose. For example, you can now
    easily use the SQL standard SUBSTRING function:

    column = :user
    pattern = params[:pattern]{|o| o.substring(’? from ?’.lit(column, pattern))}

  • A validates_inclusion_of validation method was added to Model. You
    can provide a Range or an Array in the :in option to specify the
    allowed values:

    validates_inclusion_of :value, :in=>1…5
    validates_inclusion_of :weekday, :in=>%w’Monday Tuesday …’

  • Dataset#with_sql was added, which returns a copy of the dataset
    with static SQL. This is useful if you want to keep the same
    row_proc/graph/transform/etc., but want to use your own custom

Other Improvements

  • You can now use Sequel’s database independent types when casting:

    Among other things, the default cast types for cast_string and
    cast_numeric now work in the MySQL adapter.

  • Model#set_associated_object was added. The many_to_one association
    setter method calls it. This allows you to easily override the
    association setters for all many_to_one associations of a class
    by modifying a single method.

  • Typecasting invalid date strings now raises a
    Sequel::Error::InvalidValue instead of an argument error, which
    means that you can use raise_on_typecast_failure = false and not
    have an error raised when an invalid date format is used.

  • String#to_sequel_blob was added and should now be used instead
    of String#to_blob. sqlite3-ruby defines String#to_blob
    differently, which could cause problems.

  • Blob columns are now fully supported in the SQLite adapter, with
    the hex escape syntax being used for input, and returning columns
    of type Sequel::SQL::Blob on output.

  • The SQLite adapter drop_column support is now significantly more

  • The SQLite adapter now supports rename_column.

  • The MySQL adapter now supports stored procedures with multiple

  • The MySQL adapter can now not use a compressed connection to the
    server via the :compress=>false option.

  • The MySQL adapter now sets a default timeout of 30 days to the
    database connection, you can change it via the :timeout option,
    which accepts a number of seconds.

  • The MySQL adapter now sets SQL_AUTO_IS_NULL to false by default,
    you can use the :auto_is_null=>true option to not do this.

  • The MySQL adapter now sets the encoding option on the database
    connection itself, so it works across reconnects.

  • Sequel itself no longer uses String#lit or Symbol#* internally, so
    it shouldn’t break if another library defines them.

  • The default index name is now generated correctly if a non-String
    or Symbol column is used.

  • Some ruby -w warnings have been fixed.

  • INSERTs are now sent to the master database instead of the slave
    database(s) if using a master/slave database configuration and
    PostgreSQL 8.2+ or Firebird.

  • DateTime literalization has been fixed in the Firebird adapter.

  • Date literalization has been fixed in the H2 JDBC subadapter.

  • Release notes for versions from 1.0 to the present are now included
    in the Sequel repository and the RDoc documentation, see

Backwards Compatibilty

  • The optimization of Model.[] may break if you modify the model’s
    dataset behind its back. Always use Model.set_dataset if you
    want to change a Model’s dataset.

  • Sequel::Dataset::UnsupportedExceptIntersect and
    Sequel::Dataset::UnsupportedExceptIntersectAll will now only be
    defined if you are using an adapter that requires them.

  • The private Model#cache_delete_unless_new method has been removed.

  • Sequel::SQL::IrregularFunction was removed, as it was a bad hack
    that is not used by Sequel anymore. Unless you were instantiating
    it directly or using a plugin/extension that did, this shouldn’t
    affect you. Using a Sequel::SQL::Function with a
    Sequel::SQL::PlaceholderLiteralString is recommended instead, see
    the substring example above.


This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs