Data Access Language: Difference between revisions

Revision as of 12:28, 7 August 2009

Revision as of 18:11, 7 December 2009

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On the client end, DAL was originally accessed directly through a "system extension", but DAL was later rolled into a single ODBC-like driver layer, the [[Data Access Manager]] (DAM). DAM was ODBC-like in concept, but did not include the SQL layers, it was strictly a system for sending "opaque" queries and receiving result sets. DAM also included the concept of a "query document" that allowed the DAL (or other) queries to be written in an authoring system and then easily used in any client application.

For much of the 1990s a direct-DAL database server was available on the Macintosh, '''Butler'''. However, like any server software on the "classic" Mac OS, Butler was seriously hampered by the Mac's single-user [[file system]] and [[Computer multitasking|multitasking]] and could never really deliver the sort of performance the same server would have on [[Windows NT]] or [[Unix]].

One of the more common clients for DAM was [[HyperCard]]. The combination of HyperCard and DAL presented a serious challenge to existing vendors who could offer nothing with a GUI. Apple gave a series of demos of HyperCard/DAL, and soon [[Oracle Corporation]] purchased a HyperCard-clone, PLUS from [[Spinnaker Software]], to produce [[Oracle Card]].