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 makes it easy to deal with multiple records without having
to break your teeth on SQL.
- Sequel currently has adapters for ADO, DB2, DBI, Informix, JDBC,
MySQL, ODBC, OpenBase, Oracle, PostgreSQL and SQLite3.
Sequel 2.3.0 has been released and should be available on the gem
mirrors. The 2.3.0 release focuses mainly on compatibility, and
offers the following improvements:
JRuby and Ruby 1.9 Officially Supported
Sequel now officially supports JRuby 1.1.3 and Ruby 1.9 (svn revision
18194 at least). Using JRuby with the JDBC adapter, PostgreSQL,
MySQL, and SQLite now enjoy almost full support, though not
everything works the same as using the native adapter. Depending on
what you are doing, it may make sense to use postgres-pr on JRuby
instead of PostgreSQL-JDBC.
To use the new JDBC support, the database connection string you give
Sequel is now passed directly to JDBC, here are a few examples:
Sequel is now distributed as a single gem named sequel, by combining
the previous sequel_core and sequel gems. You can still just
“require ‘sequel_core’” if you don’t want the model functionality.
Database Adapter Improvements
Dataset#empty? now works using the MySQL adapter.
The Oracle adapter now works with a nonstandard database port.
The JDBC adapter should load JDBC drivers automatically for
PostgreSQL, MySQL, SQLite, Oracle, and MSSQL. For PostgreSQL,
MySQL, and SQLite, the jdbc-* gem can be used, for the others, you
must have the correct .jar in your CLASSPATH.
The PostgreSQL adapter no longer raises an error when inserting
records into a table without a primary key.
Database#disconnect now works for the ADO adapter.
The ADO adapter no longer raises an error if the dataset contains
The ODBC adapter no longer errors when converting ::ODBC::Time
Backwards Incompatible Changes
Sequel::Worker has been removed. There are no known users, and the
specs caused problems on JRuby.
Assigning an empty string to a non-string, non-blob model attribute
converts it to nil by default. You can use
“Model.typecast_empty_string_to_nil = false” to get the old
behavior. This should make web development with Sequel
significantly easier, hopefully at no expense to other uses.
Database.uri_to_options is now a private class method.
Model.create_table! now acts the same as Database.create_table!,
dropping the table unconditionally and then creating it. This was
done for consistency. If you are using Model.create_table! in
production code, you should change it to
“Model.create_table unless Model.table_exists?”, otherwise you risk
wiping out your production data. I recommended you use the
migration feature instead of Model.set_schema, as that handles
altering existing tables.
Other Notable Changes
Using validates_length_of more than once on the same attribute with
different options without a tag no longer causes the first use to
be ignored. This was a side effect of the validation tags added
Other than the adapters, Sequel now has 100% code coverage (line
Model#set* methods now return self.
An integration test suite was added, testing Sequel against a live
database with nothing mocked, which helped greatly when testing the
new support for JDBC adapters.
If you have any questions, please post on the Google Group.