ANN: Sequel 3.18.0 Released

Ruby
1

Sequel is a lightweight database access toolkit for Ruby.

  • Sequel provides thread safety, connection pooling and a concise
    DSL for constructing SQL queries and table schemas.
  • Sequel includes a 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, savepoints,
    two-phase commit, transaction isolation, master/slave
    configurations, and database sharding.
  • Sequel currently has adapters for ADO, Amalgalite, DataObjects,
    DB2, DBI, Firebird, Informix, JDBC, MySQL, Mysql2, ODBC, OpenBase,
    Oracle, PostgreSQL, SQLite3, and Swift.

Sequel 3.18.0 has been released and should be available on the gem
mirrors.

= New Features

  • Reversible migration support has been added:

    Sequel.migration do
    change do
    create_table(:artists) do
    primary_key :id
    String :name, :null=>false
    end
    end
    end

    The change block acts the same way as an up block, except that
    it automatically creates a down block that reverses the changes.
    So the above is equivalent to:

    Sequel.migration do
    up do
    create_table(:artists) do
    primary_key :id
    String :name, :null=>false
    end
    end
    down do
    drop_table :artists
    end
    end

    The following methods are supported in a change block:

    • create_table
    • add_column
    • add_index
    • rename_column
    • rename_table
    • alter_table (supporting the following methods):
      • add_column
      • add_constraint
      • add_foreign_key (with a symbol, not an array)
      • add_primary_key (with a symbol, not an array)
      • add_index
      • add_full_text_index
      • add_spatial_index
      • rename_column

    Use of an other method in a change block will result in the
    creation of a down block that raises an exception.

  • A to_dot extension has been added that adds a Dataset#to_dot
    method, which returns a string that can be used as input to
    the graphviz dot program in order to create visualizations
    of the dataset’s abstract syntax tree. Examples:

    Both the to_dot extension and reversible migrations support
    were inspired by Aaron P.'s recent work on ActiveRecord
    and ARel.

  • The user can now control how the connection pool handles attempts
    to access shards that haven’t been configured. The default is
    still to assume the :default shard. However, you can specify a
    different shard using the :servers_hash option when connecting
    to the database:

    DB = Sequel.connect(…, :servers_hash=>Hash.new(:some_shard))

    You can also use this feature to raise an exception if an
    unconfigured shard is used:

    DB = Sequel.connect(…, :servers_hash=>Hash.new{raise …})

  • The mysql and mysql2 adapters now both support the :read_timeout
    and :connect_timeout options. read_timeout is the timeout in
    seconds for reading back results of a query, and connect_timeout
    is the timeout in seconds before a connection attempt is abandoned.

= Other Improvements

  • The json_serializer plugin will now typecast column values for
    columns with unrestricted setter methods when parsing JSON into
    model objects. It now also calls the getter method when creating
    the JSON, instead of directly taking the values from the underlying
    hash.

  • When parsing the schema for a model with an aliased table name,
    the unaliased table name is now used.

  • The SQLite adapter has been updated to not rely on the native
    type_translation support, since that will be removed in the next
    major version of sqlite3-ruby. Sequel now implements it’s own
    type translation in the sqlite adapter, similarly to how the mysql
    and postgres adapters handle type translation.

  • On SQLite, when emulating natively unsupported schema methods such
    as drop_column, Sequel will now attempt to recreate applicable
    indexes on the underlying table.

  • A more informative error message is now used when connecting fails
    when using the jdbc adapter.

  • method_missing is no longer removed from Sequel::BasicObject on
    ruby 1.8. This should improve compatibility in some cases with
    Rubinius.

= Backwards Compatibility

  • On SQLite, Sequel no longer assumes that a plain integer in a
    datetime or timestamp field represents a unix epoch time.

  • Previously, saving a model object that used the instance_hooks
    plugin removed all instance hooks. Now, only the applicable hooks
    are removed. So if you save a new object, the update instance
    hooks won’t be removed. And if you save an existing object, delete
    instance hooks won’t be removed.

  • The private Dataset#identifier_list method has been moved into the
    SQLite adapter, since that is the only place it was used.

Thanks,
Jeremy