ANN: Sequel 3.11.0 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, Amalgalite, DataObjects,
    DB2, DBI, Firebird, Informix, JDBC, MySQL, ODBC, OpenBase, Oracle,
    PostgreSQL and SQLite3.

Sequel 3.11.0 has been released and should be available on the gem
mirrors.

= New Features

  • A few new features were added to query logging. Sequel now
    includes execution time when logging queries. Queries that
    raise exceptions are now logged at ERROR level. You can now
    set the log_warn_duration attribute on the Database instance
    and queries that take longer than that will be logged at WARN
    level. By using different log levels, you can now only log
    queries that raise errors, or only log queries that take a long
    time.

    The default - Log all successful queries at INFO level

    DB.log_warn_duration = nil

    Log all successful queries at WARN level

    DB.log_warn_duration = 0

    Log successful queries that take the database more than half a

    second at WARN level, other successful queries at INFO level

    DB.log_warn_duration = 0.5

    All adapters included with Sequel have been modified to support
    the new logging API. The previous API is still available, so
    any external adapters should still work, though switching to the
    new logging API is encouraged.

  • Sequel::Model now has a require_modification flag. If not set
    explicitly, it is enabled by default if the dataset provides an
    accurate number of rows matched by an update or delete statement.
    When this setting is enabled, Sequel will raise an exception if
    you attempt to update or delete a model object and it doesn’t end
    up affecting exactly one row. For example:

    DB.create_table(:as){primary_key :id}
    class A < Sequel::Model; end
    a = A.create

    delete object from database

    a.delete

    a.require_modification = false
    a.save # no error!
    a.delete # no error!

    a.require_modification = true
    a.save # Sequel::NoExistingObject exception raised
    a.delete # Sequel::NoExistingObject exception raised

    Like many other Sequel::Model settings, this can be set on a
    global, per class, and per instance level:

    Sequel::Model.require_modification = false # global
    Album.require_modification = true # class
    album.require_modification = false # instance

  • An instance_filters plugin was added to the list of built in
    plugins, allowing you to add arbitrary filters when updating or
    destroying an instance. This allows you to continue using models
    when previously you would have had to drop down to using datasets
    to get the desired behavior:

    class Item < Sequel::Model
    plugin :instance_filters
    end

    These are two separate objects that represent the same

    database row.

    i1 = Item.first(:id=>1, :delete_allowed=>false)
    i2 = Item.first(:id=>1, :delete_allowed=>false)

    Add an instance filter to the object. This filter is in effect

    until the object is successfully updated or deleted.

    i1.instance_filter(:delete_allowed=>true)

    Attempting to delete the object where the filter doesn’t

    match any rows raises an error.

    i1.delete # raises Sequel::Error

    The other object that represents the same row has no

    instance filters, and can be updated normally.

    i2.update(:delete_allowed=>true)

    Even though the filter is now still in effect, since the

    database row has been updated to allow deleting,

    delete now works.

    i1.delete

  • An :after_connect database option is now supported. If provided,
    the option value should be a proc that takes a single argument.
    It will be called with the underlying connection object before
    connection object is added to the connection pool, allowing you
    to set per connection options in a thread-safe manner.

    This is useful for customizations you want set on every connection
    that Sequel doesn’t already support. For example, on PostgreSQL
    if you wanted to set the schema search_path on every connection:

    DB = Sequel.postgres(‘dbname’, :after_connect=>(proc do |conn|
    conn.execute(‘SET search_path TO schema1,schema2’)
    end))

  • A :test database option is now supported. If set to true, it
    automatically calls test_connection to make sure a connection can
    be made before returning a Database instance. For backwards
    compatibility reasons, this is not set to true by default, but it
    is possible that the default will change in a future version of
    Sequel.

  • The Dataset#select_append method was added, which always appends
    to the existing selected columns. It operates identically to
    select_more, except in the case that no columns are currently
    selected:

    ds = DB[:a]

    SELECT * FROM items

    ds.select_more({:id=>DB[:b].select(:a_id)}.as(:in_b))

    SELECT id IN (SELECT a_id FROM b) AS in_b FROM a

    ds.select_append({:id=>DB[:b].select(:a_id)}.as(:in_b))

    SELECT *, id IN (SELECT a_id FROM b) AS in_b FROM a

  • The Dataset#provides_accurate_rows_matched? method was added which
    allows you to see if the dataset will return the actual number of
    rows matched/affected by an update or delete call.

  • Sequel will now emulate DISTINCT ON support using GROUP BY on
    MySQL. On MySQL, GROUP BY is similar to DISTINCT ON, except that
    the order of returned rows is not deterministic.

  • Support for connecting to Microsoft SQL Server using the JTDS JDBC
    driver was added to the jdbc adapter.

  • JDNI connection strings are now supported in the JDBC adapter.

  • The JDBC adapter should now work in situations where driver
    auto-loading has problems, just as when using Tomcat or Trinidad.

  • Sequel’s JDBC adapter schema parsing now supports a :scale option,
    useful for numeric/decimal columns.

  • Sequel’s schema parsing on Microsoft SQL Server now supports
    :column_size and :scale options.

  • When connecting to SQLite, a Database#sqlite_version method is
    available that gives you the SQLite version as an integer (e.g.
    30613 for 3.6.13).

= Other Improvements

  • Sequel no longer raises an error if you give Dataset#filter or
    related method an empty argument such as {}, [], or ‘’. This allows
    code such as the following to work:

    h = {}
    h[:name] = name if name
    h[:number] = number if number
    ds = ds.filter(h)

    Before, this would raise an error if both name and number were
    nil.

  • Numeric and decimal columns with a 0 scale are now treated as
    integer columns by the model typecasting code, since such columns
    cannot store non-integer values.

  • Calling Database#disconnect when using the single threaded
    connection pool no longer raises an error if there is no current
    connection.

  • When using the :ignore_index_errors options to
    Database#create_table, correctly swallow errors raised by Sequel
    due to the adapter not supporting the given index type.

  • The JDBC adapter no longer leaks ResultSets when retrieving
    metadata.

  • You can now connect to PostgreSQL when using ruby 1.9 with the
    -Ku switch.

  • When using the native MySQL adapter, only tinyint(1) columns are
    now returned as booleans when using the convert_tinyint_to_bool
    setting (the default). Previously, all tinyint columns would
    be converted to booleans if the setting was enabled.

  • Correctly handle inserts returning the autogenerated keys when
    using MySQL JDBC Driver version 5.1.12 with the jdbc adapter.

  • The native MySQL adapter now supports :config_default_group and
    :config_local_infile options.

  • When connecting to SQLite, you can provide the :auto_vacuum,
    :foreign_keys, :synchronous, and :temp_store options for
    making the appropriate PRAGMA setting on the database in a
    thread-safe manner. The previous thread-unsafe PRAGMA setting
    methods are available, but their use is discouraged.

  • Sequel will not enable savepoints when connecting to SQLite
    unless the version is 3.6.8 or greater.

  • Using limit with distinct now works correctly on Microsoft SQL
    Server.

  • Database#rename_table now works correctly on Microsoft SQL Server.

  • If you specify an explicit :provider when using the ADO adapter,
    transactions will now work correctly. The default :provider uses
    a new native connection for each query, so it cannot work with
    transactions, or things like temporary tables.

  • If you specify an explicit :provider when connecting to Microsoft
    SQL Server using the ADO adapter (e.g. SQLNCLI10 or SQLNCLI),
    Sequel is now able to provide an accurate number of rows modified
    and deleted.

  • Using set_column_allow_null with a decimal column with a precision
    and scale now works correctly when connecting to Microsoft SQL
    Server.

  • You can now connect to Microsoft SQL Server using the dbi adapter.

  • Sequel now recognizes the NUMBER database type as a synonym for
    NUMERIC and DECIMAL, which may help some Oracle users.

  • Transactions can now be rolled back correctly when connecting to
    Oracle via JDBC.

  • The active_model plugin now supports ActiveModel 3.0.0beta2.

  • Many documentation improvements were made, including the addition
    of a dataset basics guide, an association basics guide, an expanded
    virtual row guide, and the separation of the Sequel::Dataset RDoc
    page into sections. Additional, the RDoc class/method
    documentation now contains links to the appropriate guides.

= Backwards Compatibility

  • When connecting to SQLite, Sequel now automatically sets the
    foreign_keys PRAGMA to true, which will make SQLite 3.6.19+ use
    database enforced foreign key constraints. If you do not want
    the database to enforce the foreign key constraints, you should
    use the :foreign_keys=>false option when connecting to the
    database.

  • Sequel no longer creates #{plugin_name}_opts class, instance, and
    dataset methods for each plugin loaded. No built-in plugin used
    them, and I couldn’t find an external plugin that did either.

  • The Model#associations method is no longer available if the
    default Associations plugin is not loaded due to the
    SEQUEL_NO_ASSOCIATIONS constant or environment variable being set.

  • DISTINCT ON support is turned off by default, and only enabled when
    using PostgreSQL, since that appears to be the only database that
    supports it. Previously, it was enabled by default and most common
    adapters turned it off.

Thanks,
Jeremy

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