Rel version 3.004 now available!

This is a maintenance release of Rel, an implementation of Date & Darwen’s Tutorial D database language. It fixes some bugs, and provides some minor enhancements including a faster GROUP operator, the ability to use Unicode character symbols for certain operators, and makes refinements to the Rel user interface.

The following enhancements have been made:

Case #133: The Rel command-line’s ‘Save’ operation’s default filename and path is now set to the filename and path of the most recent ‘Load file’ operation.

!!SP or !!(SP) is now equivalent to IMAGE_IN(SP), and !!(SP, TUP{x 1}) is equivalent to IMAGE_IN(SP, TUP {x 1}). This brings Rel into line with Date & Darwen’s “Database Explorations” text.

The following Unicode operator symbols are now supported:
≤ Less than or equal
≥ Greater than or equal
≠ Not equal
× Scalar multiplication
÷ Scalar division
‼ Image in (see above)
⊂ Proper subset
⊆ Subset
⊃ Proper superset
⊇ Superset
∈ Is element of (alias for IN)

In the Rel user interface’s command-line entry panel (the lower panel of any command-line), a button has been provided to launch a dialog box to facilitate entering the above Unicode operators.

The GROUP operator is now significantly faster, at the expense of somewhat increased memory consumption.

Note: The Unicode support described above has been found to be buggy on (at least) Windows 7 and Windows 10. This will be corrected in a future update. It works correctly on OS X and Linux.

The following bugs have been fixed:

Case #134: In the Rel user interface, the command-line entry panel now consistently focuses on highlighted errors. This makes it possible to immediately type a correction without having to click on the entry panel.

Due to a bug in the GROUP operator, the following produced an incorrect result:

RELATION {TUPLE {SID 1, PID 1}, TUPLE {SID 4, PID 5}} GROUP {PID}
AS PARTS UNION RELATION {TUPLE {SID 1, PARTS RELATION {TUPLE
{PID 1}}}, TUPLE {SID 4, PARTS RELATION {TUPLE {PID 5}}}}

This has been corrected.

In the Rel user interface’s visual query language, the “View Query” ‘?’ dialog invoked from any query node no longer crashes after changing mode.

In the Rel user interface, viewing a VIEW or relvar with no attributes no longer crashes.

In the Rel user interface, the ‘Zoom in or out’ button in the command-line mode is now positioned correctly in its toolbar. Previously, it was positioned too far to the right.

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