# ANN: Sequel 3.5.0 Released **URL:** \ **Category:** Ruby\ **Created:** [October 1, 2009, 6:10pm UTC](https://www.ruby-forum.com/t/ann-sequel-3-5-0-released/176530 "2009-10-01T18:10:35Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![nerdmaster](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/c68b51/32.png) [@nerdmaster](https://www.ruby-forum.com/u/nerdmaster)\ **Post date:** [October 1, 2009, 6:10pm UTC](https://www.ruby-forum.com/t/ann-sequel-3-5-0-released/176530/1 "2009-10-01T18:10:35Z")
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 3.5.0 has been released and should be available on the gem mirrors. The 3.5.0 release adds numerous improvements: ## New Plugins - A class\_table\_inheritance plugin has been added, supporting model inheritance in the database using a table-per-model-class approach. Each table stores only attributes unique to that model or subclass hierarchy. - An associations\_dependencies plugin was added for deleting, destroying, or nullifying associated objects when destroying a model object. This just gives an easy way to add the necessary before and after destroy hooks. The following association types support the following dependency actions: - A force\_encoding plugin was added that forces the encoding of strings used in model instances. When model instances are loaded from the database, all values in the hash that are strings are forced to the given encoding. Whenever you update a model column attribute, the resulting value is forced to a given encoding if the value is a string. There are two ways to specify the encoding. You can either do so in the plugin call itself, or via the forced\_encoding class accessor: - A typecast\_on\_load plugin was added, for fixing bad database typecasting when loading model objects. Most of Sequel’s database adapters don’t have complete control over typecasting, and may return columns that aren’t typecast correctly (with correct being defined as how the model object would typecast the same column values). - A touch plugin was added, which adds Model#touch for updating an instance’s timestamp, as well as touching associations when an instance is updated or destroyed. - A subclasses plugin was added, for recording all of a models subclasses and descendent classes. Direct subclasses are available via the subclasses method, and all descendent classes are available via the descendents method: - An active\_model plugin was added, giving Sequel::Model an ActiveModel complaint API, in so much as it passes the ActiveModel::Lint tests. ## New Extensions - A named\_timezones extension was added, allowing you to use named timezones such as “America/Los\_Angeles” (the default Sequel timezone support only supports UTC or local time). This extension requires TZInfo. It also sets the Sequel.datetime\_class to DateTime, so database timestamps will be returned as DateTime instances instead of Time instances. This is because ruby’s Time class doesn’t support timezones other than UTC and local time. - A thread\_local\_timezones extension was added. This allows you to set a per-thread timezone that will override the default global timezone while the thread is executing. The main use case is for web applications that execute each request in its own thread, and want to set the timezones based on the request. The most common example is having the database always store time in UTC, but have the application deal with the timezone of the current user. That can be done with: - An sql\_expr extension was added that adds .sql\_expr methods to all objects, giving them easy access to Sequel’s DSL: - A looser\_typecasting extension was added, for using to\_f and to\_i instead of the more strict Kernel.Float and Kernel.Integer when typecasting floats and integers. To use it, you should extend the database with the Sequel::LooserTypecasting module after loading the extension: ## Other New Features - Associations now support composite keys. All of the :\*key options options now accept arrays of symbols instead of plain symbols. Example: - Associations now respect a :validate option, which can be set to false to not validate when implicitly saving associated objects. - In addition to the regular association methods, the nested\_attributes plugin was also updated to respect the :validate\_association option. It was also modified to not validate associated objects twice, once when the parent object was validated and again when the associated object was saved. Additionally, if you pass :validate=\>false to the save method when saving the parent object, it will not longer attempt to validate associated objects when saving them. - Dataset#insert and #insert\_sql were refactored and now support the following API: - Graphing now works with previously joined datasets. The main use case of this is when eagerly loading (via eager\_graph) model associations for models backed by joined datasets, such as those created by the class\_table\_inheritance plugin. - Sequel.virtual\_row was added allowing you to easily use the VirtualRow support outside of select, order, and filter calls: - When Sequel wraps exception in its own classes (to provide database independence), it now keeps the wrapped exception available in a wrapped\_exception accessor. This allows you to more easily determine the wrapped exception class, without resorting to parsing the exception message. - The MySQL adapter now supports a Dataset#split\_multiple\_result\_sets method that yields arrays of rows (one per result set), instead of rows. This allows you to submit multiple statements at the same time (or call a stored procedure that returns multiple result sets), and know which rows are related to which result sets. - The ADO adapter now accepts a :conn\_string option and uses that as the full ADO connection string. This can be used to connect to any datasource ADO supports, such as Microsoft Excel. - The Microsoft SQL Server shared adapter now supports a Database#server\_version method. - The Microsoft SQL Server shared adapter now supports updating and deleting from joined datasets. - The Microsoft SQL Server shared adapter now supports a Dataset#output method that uses the OUTPUT clause. - Model#\_save now calls either Model#\_insert or Model#\_update for inserting/updating the row in the database. This allows for easier overriding when you want to allow creating and updating model objects backed by a joined dataset. - Dataset#graph now takes a :from\_self\_alias option specifying the alias to use for the subselect created if the receiver is a joined but not yet graphed dataset. It defaults to the first source table in the receiver. ## Other Improvements - Typecasting model attributes is now done before checking existing values, instead of after. Before, the code for the model attribute setters would compare the given value to the existing entry. If it didn’t match, the value was typecasted and then assigned. That led to the following situation: - Model#modified? is now always true if the record is new. modified? indicates the instance’s status relative to the database, and since a new object is not yet in the database, and saving the object would add it, the object is considered modified. A consequence of this is that Model#save\_changes now always saves if the object is new. - The DataObjects (do) adpater now supports DataObjects 0.10. - Dataset#select\_more and Dataset#order\_more no longer affect the receiver. They are supposed to just return a modified copy of the receiver instead of modifying the receiver itself. For a few versions they have been broken in that they modified the receiver in addition to returning a modified copy. - Performance was increased for execution of prepared statements with multiple bound variables on MySQL. - On MySQL, database errors raised when preparing statements or setting bound variable values are now caught and raised as Sequel::DatabaseErrors. - On MySQL, more types of disconnection errors are detected. - When altering columns in MySQL, options such as :unsigned, :elements, and :size that are given in the call are now respected. - MySQL enum defaults are now handled correctly in the schema dumper. - The schema dumper no longer attempts to use unparseable defaults as literals on MySQL, since MySQL does not provide defaults as valid literals. - The emulated offset support in the shared Microsoft SQL Server adapter now works better with model classes (or any datasets with row\_procs). - Microsoft SQL Server now supports using the WITH clause in delete, update, and insert calls. - Parsed indexes when connecting to Microsoft SQL Server via JDBC no longer include primary key indexes. - Dataset#insert\_select now returns nil if disable\_insert\_returning is used in the shared PostgreSQL adapter. This makes it work as expected with model object creation. - Calling Model.set\_primary\_key with an array of symbols to set a composite primary key is now supported. You can also provide multiple symbol arguments to do the same thing. Before, specifying an array of symbols broke the Model.[] optimization. - Literalization of timezones in timestamps now works correctly on Oracle. - **FILE** and **LINE** are now used everywhere that eval is called with a string, which makes for better backtraces. - The native MySQL adapter now correctly handles returning before yielding all result sets. Previously, this caused a commands out of sync error. - Table names in common table expressions are now quoted. - The Oracle adapter’s Dataset#except now accepts a hash, giving it the same API as the default Dataset#except. - When connecting to Microsoft SQL Server via ADO, allow Dataset#insert to take multiple arguments. - Fractional timestamps are no longer used on ODBC. - Schema parsing now works on MSSQL when the database is set to not quote identifiers. - Timezone offsets are no longer used on Microsoft SQL Server, since they only work for the datetimeoffset type. - Only 3 fractional digits in timestamps are used in Microsoft SQL Server, since an error is raised if the use the datetime type with more than that. - The integration test suite now has guards for expected failures when run on known databases. Expected failures are marked as pending. ## Backwards Compatibility - Graphing to an previously joined (but not graphed) dataset now causes the receiver to be wrapped in a subselect, so if you graph a dataset to a previously joined dataset, and then filter the dataset referring to tables that were in the joined dataset (other than the first table), the SQL produced will probably no longer be valid. You should either filter the dataset before graphing or use the name of the first source of the joined dataset (which is what the subselected is aliased to) if filtering afterward. - The DataObjects (do) adpater no longer supports DataObjects 0.9.x. - The Dataset#virtual\_row\_block\_call private instance method has been removed. - Sequel’s timezone support was significantly refactored, so if you had any custom modifications to the timezone support, they might need to be refactored as well. - The SQL generation code was significantly refactored, so if you had any custom modifications in that area, you might need to refactor as well. Thanks, Jeremy - {Website}[[http://sequel.rubyforge.org](http://sequel.rubyforge.org)] - {Source code}[[GitHub - jeremyevans/sequel: Sequel: The Database Toolkit for Ruby](http://github.com/jeremyevans/sequel)] - {Bug tracking}[[Google Code Archive - Long-term storage for Google Code Project Hosting.](http://code.google.com/p/ruby-sequel/issues/list)] - {Google group}[[http://groups.google.com/group/sequel-talk](http://groups.google.com/group/sequel-talk)] - {RDoc}[[http://sequel.rubyforge.org/rdoc](http://sequel.rubyforge.org/rdoc)]