Codd’s 12 Rules (for a relational database product) are (still) frequently informally cited, but their original text turns out to be annoyingly difficult to find. They are reprinted here under the principles of fair use and/or fair dealing and have been extracted, verbatim, from ‘Is your DBMS really relational?’, Computerworld. Oct 14, 1985, Vol. 19, Read more about Codd’s Twelve Rules[…]

This release of Rel, an implementation of Date & Darwen’s Tutorial D database language, improves the user interface, fixes some bugs, adds support for outer joins, and significantly reduces the size of the Rel distribution whilst improving startup speed. The following enhancements have been made: – The Rel user interface (known as DBrowser) provides same familiar interface but now has significantly fewer Read more about Rel version 3.013 now available![…]

This release of Rel, an implementation of Date & Darwen’s Tutorial D database language, improves the user interface and fixes some bugs. The following enhancements have been made: – Rel DBMS: Now provides -q command-line option to disable startup/shutdown information messages. This is intended to make it easier to implement standalone scripts that produce console Read more about Rel version 3.012 now available![…]

This release of Rel, an implementation of Date & Darwen’s Tutorial D database language, improves the user interface and fixes some bugs. The following enhancements have been made: – Rel UI: Opening a relvar in Edit mode now positions the cursor in the blank row at the bottom, ready to enter a new tuple. Cursor Read more about Rel version 3.011 now available![…]

This release of Rel, an implementation of Date & Darwen’s Tutorial D database language, improves the user interface and fixes some bugs.   The following enhancements have been made to the user interface: Drop-down menus are now provided for most major operations. Double-clicking on a database tree item causes focus to be set to the contents Read more about Rel version 3.010 now available![…]

This is a minor bug-fix release of Rel, an implementation of Date & Darwen’s Tutorial D database language. A performance problem has been corrected that caused slow database loading and interaction on some networks. The Java JRE has been updated to version 8u151. For more information, or to download Rel, go to http://reldb.org

This is a minor bug-fix release of Rel, an implementation of Date & Darwen’s Tutorial D database language. There was a bug in INSERT that caused additional KEY constraints to be ignored. For example, given the following: VAR myvar REAL RELATION {x INT, y INT} KEY {x} KEY {y}; INSERT myvar REL {TUP {x 1, Read more about Rel version 3.008 now available![…]

This is a minor release of Rel, an implementation of Date & Darwen’s Tutorial D database language. It adds EQUIV and RANK operators, slightly tweaks the Tutorial D grammar implementation to reduce the need for parentheses, provides infix invocation for certain operators, and fixes some bugs. The following enhancements have been made to the Rel Read more about Rel version 3.007 now available![…]

This is a minor maintenance release of Rel, an implementation of Date & Darwen’s Tutorial D database language. It makes some improvements to the Rel user interface, now provides a selection of built-in operators that previously had to be loaded from a script, and fixes various minor bugs. IMPORTANT NOTE: Once opened with this or Read more about Rel version 3.006 now available![…]

This is a minor maintenance release of Rel, an implementation of Date & Darwen’s Tutorial D database language. It makes some improvements to the Rel user interface, adds some system relvars, and fixes two bugs. IMPORTANT NOTE: Once opened with this or later versions of Rel, databases cannot be read by earlier versions. The following Read more about Rel version 3.005 now available![…]