Archive for September, 2009

September 22, 2009

Videos to get acquainted with Apache Derby and Java DB

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Kristian Wagaan and Richard Hillegas, both Apache Derby committers who also work on Java DB, recently gave some great presentations about Apache Derby and Java DB.

Kristian Wagaan presented at the 2009 OpenSQLCamp, in conjunction with FrOSCon 2009 in Europe.

The presentation (slides) gives a brief overview of Apache Derby, its history and the community around it. Further, it goes into the details of features that have been added in the latest releases and show how they enable powerful ways to use a relational database.

Rick Hillegas gave an introduction of Java DB / Apache Derby at The San Francisco Java User Group’s Sep 8th event in San Francisco.

September 14, 2009

Java DB 10.5.3 is now available

Following the release of Apache Derby 10.5.3, Java DB which is Sun’s supported version of this last one is also now available.

Java DB 10.5.3 is primarily a bug-fix release and inherits all the bug fixes and localized messages from Apache Derby 10.5.3.

Java DB offers installers for the following platforms:

  • Solaris
  • Linux
  • Windows
  • Mac OS X (newly added)

Here is a recap of all changes that are coming as part of Java DB 10.5.3:

  • SQL Roles – SQL roles (as described in SQL
    2003 and errata) are useful for administering privileges for groups of
    users. Administering roles is generally less error-prone than
    administering privileges for individual users. SQL Roles are defined in
    Feature T331 "Basic roles" and Feature T332 "Extended roles". Java DB
    10.5 implements a subset of T331, plus support for CURRENT_ROLE, which
    is a part of T332.

  • Generated Columns – Generated Columns is a
    feature which instructs Java DB to fill a column with an expression
    built out of other columns in the row. Java DB constructs these column
    values at INSERT and UPDATE time. The user declares indexes on these
    columns. This in turn improves SELECT performance since it lets users
    declare indexes on pre-computed pieces of the WHERE clause. This
    feature satisfies support for SQL Feature T175.

  • LOB Improvements – There were many performance and usability improvements for BLOBs and CLOBs.

  • Replication of encrypted databases – With 10.5 it is possible to replicate encrypted databases.

  • OFFSET/FETCH FIRST – SQL 2008 has added new
    syntax to support a direct way to limit the returned set of rows in a
    result set, through the fetch first and offset clauses.

  • In-memory back end – Initial implementation of
    a storage engine for Java DB where all data is kept in memory. There is
    no documentation for this feature. This functionality itself is not yet
    fully implemented, but users are welcome to experiment with it. For
    details, see the Primer for In-memory Back Ends.

  • Standard ALTER COLUMN syntax – Allow standard
    SQL "SET" keyword in ALTER COLUMN syntax, like so: "ALTER TABLE ALTER
    COLUMN columnname SET DEFAULT default-value"

  • SYSCS_UTIL.SYSCS_UPDATE_STATISTICS
    New system procedure that updates cardinality statistics (or creates
    them if they do not exist) for a table’s index or for all the indexes
    on a table, allowing a user to ensure that a query plan based on the
    most recent state of the table can be created.

  • Service tag – Introduction of the Java DB registration service (service tag).

Further details on new features, changes, and issues in this release can be found in the Release Notes.