Rel / News: Recent posts

Rel version 1.0.12 Released!

This update to Rel -- an implementation of Date & Darwen's Tutorial D database language -- is a maintenance release featuring some enhancements and bug fixes. See http://dbappbuilder.sourceforge.net for more information, or to download.

Posted by Dave Voorhis 2014-10-26

Rel version 1.0.11 Released!

This update to Rel -- an implementation of Date & Darwen's Tutorial D database language -- is a maintenance release featuring various enhancements and bug fixes.

Posted by Dave Voorhis 2014-07-17

Rel version 1.0.10 Released!

This version of Rel -- an implementation of Date & Darwen's "Tutorial
D" database language -- is a significant release, as it implements the
latest Tutorial D syntax from Date and Darwen's book "Database
Explorations: Essays on The Third Manifesto and related topics" (ISBN
978-1426937231) This update also includes various bug fixes.

Posted by Dave Voorhis 2013-02-26

Rel version 1.0.9 released!

This version of Rel -- an implementation of Date & Darwen's Tutorial D database language -- is a maintenance release featuring various enhancements and bug fixes.

For example, unicode support is now explicitly provided in Rel, DBrowser, and the RelClient middleware. This should reduce the likelihood of errors or incorrect character translations when inputting unicode characters. Crashes, should they unfortunately occur, will now automatically open a dialog box to allow the user to send an error report to the developers.... read more

Posted by Dave Voorhis 2012-06-04

Rel version 1.0.7 released.

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- is a minor release featuring the following fixes and enhancements:

  1. Enhancement: New built-in operator GET_UNIQUE_NUMBER returns an integer guaranteed to be unique in a given database.

  2. Fix: Given TYPE POSINT IS {INTEGER CONSTRAINT INTEGER > 0}, MAX(RELATION {TUPLE {X 1}, TUPLE {X 2}}, X) failed due to a missing target. Fixed.... read more

Posted by Dave Voorhis 2011-10-19

Rel version 1.0.6 released

Rel, an implementation of Date & Darwen's "Tutorial D" database language, now supports some of the changes found in their new book, "Database Explorations - Essays on The Third Manifesto and Related Topics".

In particular, aggregate operator invocations now allow you to specify expressions in addition to attributes, and short synonyms have been provided for various keywords.

For more information, or to download Rel, see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2011-02-26

Rel version 1.0.5 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- is a maintenance release featuring two bug fixes: A bug in how relation literals were parsed has been corrected, and a bug related to transaction processing has been fixed.

Posted by Dave Voorhis 2010-11-07

Rel version 1.0.4 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- provides two enhancements and several bug fixes. The enhancements improve the type system implementation, and the bugs fixes increase reliability.

For more information, or to download Rel, see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2010-09-12

Rel version 1.0.3 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- is a maintenance release.

A Java exception could occur when performing a JOIN on relations with common attributes that belong to a user-defined TYPE with at least one relation-valued component. This has been corrected.

For more information, or to download Rel, see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2010-07-26

Rel version 1.0.2 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- is a maintenance release.

A bug has been fixed in the Rel DBMS. In some cases, the superset operator '>=' did not work correctly. This has been corrected.

For more information, or to download Rel, see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2010-07-14

Rel version 1.0.1 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- is a maintenance release. Five bugs -- four in the Rel server, and one in the DBrowser front-end -- have been fixed.

For more information, or to download Rel, see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2010-07-12

Rel version 1.0.0 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- represents an important milestone. It has been updated from 'Alpha' to 'Beta' status and the version number set to 1.0.0. Whilst not yet at a point where it should be used to host the company payroll, the new version number and status reflect that fact that Rel is increasingly stable and usable as a "real" DBMS and not just a teaching tool.... read more

Posted by Dave Voorhis 2010-06-04

Rel version 0.3.20 released

This version of Rel makes major changes to the type system. It is now
possible to create subtypes of the built-in INTEGER, BOOLEAN,
RATIONAL, and CHARACTER types. The <, <=, >, >=, =, <>, AND, OR, XOR,
NOT, +, -, *, and / symbolic operators have been mapped to named
operators, all of which have a name prefixed with OP_. This makes it
straightforward to create appropriate operators for user-defined types
and subtypes, simply by defining new OP_ operators.... read more

Posted by Dave Voorhis 2010-04-05

Rel version 0.3.19 released

This version of Rel -- an implementation of Date and Darwen's "Tutorial D" database language -- fixes three bugs. For further information or to download Rel, please see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2010-02-28

Rel version 0.3.18 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- fixes some bugs and makes a change to how tagged union types are defined. For further information or to download Rel, please see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2009-12-29

Rel version 0.3.17 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- fixes some bugs in the single inheritance and specialization by constraint mechanisms. For further information or to download Rel, please see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2009-05-31

Rel version 0.3.16 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- now provides preliminary support for single inheritance and specialization by constraint. For further information or to download Rel, please see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2009-05-25

DBAppBuilder: Rel version 0.3.15 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- is the first to provide preliminary support for user-defined types. For further information or to download Rel, please see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2009-04-14

DBAppBuilder: Rel version 0.3.14 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- provides several fixes and enhancements to DBrowser, and corrections a problem with aggregate operators. For further information or to download Rel, please see http://dbappbuilder.sourceforge.net/Rel.html

Posted by Dave Voorhis 2009-03-25

DBAppBuilder: Rel version 0.3.13 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- includes several fixes and enhancements:

First, the fixes:

  • In some cases, an expression that used the result of one WHERE operator as input to another WHERE operator would generate bogus results or throw an exception. This has been corrected.

  • JOINing relations with relation-valued attributes could cause an exception. This has been corrected.... read more

Posted by Dave Voorhis 2008-10-16

DBAppBuilder: Rel version 0.3.12 released

This version of Rel -- an implementation of Date
& Darwen's "Tutorial D" database language --
includes some significant changes to ORDER and
FOR.

Previously, ORDER was a relational operator that returned tuples in a
specified order, and FOR iterated over the tuples of a relation. Now,
ORDER is an array operator that accepts a relation and returns a
dynamically-created ARRAY, and FOR iterates over the tuples of an
ARRAY. This requires no syntactic changes to existing Tutorial D /
Rel scripts, but Relationland is no longer corrupted with notions of
tuple order or tuple iteration.... read more

Posted by Dave Voorhis 2008-08-04

DBAppBuilder: Rel version 0.3.11 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D"
database language -- includes a number of bug fixes and enhancements,
primarily focusing on the Rel DBMS.

The following bugs have been fixed in Rel:

  1. Assigning a relvar to itself (e.g., myrelvar := myrelvar) could
    result in the Rel session becoming non-responsive. This has been
    corrected.

  2. Under certain conditions, updating a key attribute in a relvar
    could result in the Rel session becoming non-responsive. This has
    been corrected.... read more

Posted by Dave Voorhis 2008-08-01

DBAppBuilder: Rel version 0.3.9 released

This version of Rel -- an implementation of Date & Darwen's "Tutorial D" database language -- includes a number of changes.

New features have been added to DBrowser:

  1. DBrowser shows the percentage of available memory in the lower right-hand corner of the window.

  2. DBrowser goes to greater effort to trap errors, including running out of memory, and shut down gracefully if possible.

  3. DBrowser preserves the main window position and size across invocations.... read more

Posted by Dave Voorhis 2008-07-29

DbAppBuilder: Rel version 0.3.8 released

Rel, an implementation of Date & Darwen's "Tutorial D" database language, has released version 0.3.8 Alpha.

This release provides the following features:

  • A "Backup" button in DBrowser to automatically make a database backup.

  • The installer now creates "Start" menu entries and optional desktop shortcuts under Linux and Microsoft Windows.

This release also fixes the following bugs:... read more

Posted by Dave Voorhis 2008-07-14

DbAppBuilder: Rel version 0.3.7 released

Rel, an implementation of Date & Darwen's "Tutorial D" database language, has released version 0.3.7. This update improves the user-interface, which now provides formatted display of tuples and relations, HTML export, and an indication of the number of tuples affected by database update operations.

Posted by Dave Voorhis 2008-07-11