Rel version 0.3.9 Alpha now available

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Dave
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Joined: Sun Nov 27, 2005 7:19 pm

Rel version 0.3.9 Alpha now available

Post by Dave » Tue Jul 29, 2008 12:47 am

This version of Rel 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.

4. DBrowser includes a "DBrowser Monitor" window, which displays log messages and provides buttons to terminate DBrowser (for example, if it runs out of memory) and restart it.

The underlying Rel DBMS also includes new features:

1. A relational operator, ORDER, has been provided to sort a relation. For example...

sys.Catalog ORDER (ASC Name)

...will display the system catalog sorted by name. This operator is only intended as the final operator in an expression, to sort the result for some user-oriented purpose. It has no meaning except as the final operator in a relational expression.

2. A new loop statement, FOR, has been provided to iterate the tuples of a relation. It should be considered shorthand for loading a relation into an array, then iterating the tuples of the array, plus creating local constants -- initialised to the current tuple's attribute values -- with the same names as the tuple attributes.

3. The DatabaseToScript.d backup script (found in the Scripts directory) has been simplified, and revised to use FOR and ORDER.

4. The grammar has been tweaked slightly to avoid the need for extraneous parentheses in some cases. For example, the expression (UNION {a, b, c}) = (UNION {d, e, f}) can now be expressed as UNION {a, b, c} = UNION {d, e, f}.

The installation scripts have been slightly modified under UNIX/Linux. The "Uninstall" option has been renamed to "Uninstall Rel", in order to avoid ambiguity on systems where the Rel menu entries are merged with other menu entries.

Two bugs have been fixed in DBrowser:

1. Previously, repeatedly switching between Enhanced and non-enhanced display caused a memory leak that would eventually cause DBrowser to run out of memory. This has been corrected.

2. The DBrowser "splash" window that appears on start-up has been widened, to prevent the text overflowing the window on some systems.

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

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