* 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, 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, DB2, DBI, Informix, JDBC,
MySQL, ODBC, OpenBase, Oracle, PostgreSQL and SQLite3.
Sequel 2.8.0 has been released and should be available on the gem
mirrors. The 2.8.0 release adds numerous improvements:
New Features
···
------------
* Sequel now supports database stored procedures similar to its
support for prepared statements. The API is as follows:
DB[:table].call_sproc(:select, :mysp, 'param1', 'param2')
# or
sp = DB[:table].prepare_sproc(:select, :mysp)
sp.call('param1', 'param2')
sp.call('param3', 'param4')
This works with Model datasets as well, allowing them to return
model objects:
Album.call_sproc(:select, :new_albums)
#=> [#<Album ...>, #<Album ...>]
You can call a stored procedure directly on the Database object
if you want to, but the results and API are adapter dependent,
and you definitely shouldn't do it if the stored procedure returns
rows:
DB.call_sproc(:mysp, :args=>['param1', 'param2'])
Currently, the MySQL and JDBC adapters support stored procedures.
Other adapters may support them in a future version.
* The connection pool code can now remove connections if the
adapter raises a Sequel::DatabaseDisconnectError indicating that
the connection has been lost. When a query is attempted and
the adapter raises this error, the connection pool removes the
connection from the pool, and reraises the error. The Oracle and
PostgreSQL adapters currently support this, and other adapters may
support it in a future version.
* Whether to upcase or quote identifiers can now be set separately.
Previously, upcasing was done when quoting except when using SQLite,
PostgreSQL, or MySQL. Now, you can turn upcasing off while still
quoting. This may be necessary if you are using a MSSQL database
that has lower case table names that conflict with reserved words.
It also allows you to uppercase identifiers when using SQLite,
PostgreSQL, or MySQL, which may be beneficial in certain cases.
To turn upcasing on or off:
# Global
Sequel.upcase_identifiers = true
# Database
DB = Sequel.connect("postgres://...", :upcase_identifiers=>true)
DB.upcase_identifiers = false
# Dataset
ds = DB[:items]
ds.upcase_identifiers = true
* Options are now supported when altering a columns type:
DB.alter_table(:items) do
set_column_type :score, :integer, :unsigned=>true
set_column_type :score, :varchar, :size=>30
set_column_type :score, :enum, :elements=>['a', 'b']
end
* Standard conforming strings are now turned on by default in the
PostgreSQL adapter. This makes PostgreSQL not interpret backslash
escapes. This is the PostgreSQL recommended setting, which will be
the default setting in a future version of PostgreSQL. If you
don't want for force the use of standard strings, use:
Sequel::Postgres.force_standard_strings = false
You need to do that after you call Sequel.connect but before you
use the database for anything, since that setting is set on
initial connection.
* Sequel now raises an error if you attempt to use EXCEPT [ALL] or
INTERSECT [ALL] on a database that doesn't support it.
* Sequel now raises an error if you attempt to use DISTINCT ON with
MySQL or Oracle, which don't support it.
* A subadapter for the Progress RDBMS was added to the ODBC adapter.
To connect to a Progress database, use the :db_type=>'progress'
option. This adapter targets Progress 9.
* The ODBC adapter now supports transactions.
* The MSSQL shared adapter now supports multi_insert (for inserting
multiple rows at once), and unicode string literals.
Other Improvements
------------------
* There were many improvements related to using schemas in databases.
Using schema-qualified tables should work in most if not all cases
now. Model associations, getting the schema, joins, and many other
parts of Sequel were modified to allow the use of schema-qualifed
tables.
* You can now use literal strings with placeholders as well as
subselects when using prepared statements. For example, the
following all work now:
DB[:items].filter("id = ?", :$i).call(:select, :i=>1)
DB[:items].filter(:id=>DB[:items].select(:id)\
.filter(:id=>:$i)).call(:select, :i=>1)
DB["SELECT * FROM items WHERE id = ?", :$i].call(:select, :i=>1)
* Model#initialize received a few more micro-optimizations.
* Model#refresh now clears the changed columns as well as the
associations.
* You can now drop columns inside a transaction when using SQLite.
* You can now submit multiple SQL queries at once in the MySQL
adapter:
DB['SELECT 1; SELECT 2'].all
#=> [{:"1"=>1, :"2"=>2}]
This may fix issues if you've seen a MySQL "commands out of sync"
message. Note that this doesn't work if you are connecting to
MySQL via JDBC.
* You can now use AliasedExpressions directly in table names given
to join_table:
DB.from(:i.as(:j)).join(:k.as(:l), :a=>:b)
#=> ... FROM i AS j INNER JOIN k AS l ON (l.a = j.b)
* Database#rename_table once again works on PostgreSQL. It was
broken in 2.7.0.
* The interval type is now treated as it's own type. It was
previously treated as an integer type.
* Subselects are now aliased correctly when using Oracle.
* UNION, INTERSECT, and EXCEPT statements now appear before ORDER
and LIMIT on most databases. If you use these constructs, please
test and make sure that they work correctly with your database.
* SQL EXCEPT clause now works on Oracle, which uses MINUS instead.
* Dataset#exists now returns a LiteralString, to make it easier to
use.
* The Sequel.odbc_mssql method was removed, as the odbc_mssql adapter
was removed in a previous version. Instead, use:
Sequel.odbc(..., :db_type=>'mssql')
Backwards Compatibilty
----------------------
* The hash returned by Database#schema when no table name is provided
uses quoted strings instead of symbols as keys. The hash has a
default proc, so using the symbol will return the same value as
before, but if you use each to iterate through the hash, the keys
will be different. This was necessary to handle schema-qualified
tables.
* Database#table_exists? no longer checks the output of
Database#tables. If the table exists in the schema, it returns
true, otherwise, it does a query. This was necessary because
table_exists? accepts multiple formats for table names and
Database#tables is an array of symbols.
* When getting the schema on PostgreSQL, the default schema is now
used even if the :schema=>nil option is used.
Thanks,
Jeremy
* {Website}[http://sequel.rubyforge.org]
* {Source code}[http://github.com/jeremyevans/sequel]
* {Bug tracking}[http://code.google.com/p/ruby-sequel/issues/list]
* {Google group}[http://groups.google.com/group/sequel-talk]
* {RDoc}[http://sequel.rubyforge.org/rdoc]
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