[1] APL was developed to provide high-level language data access and manipulation functions to support GM's CADANCE interactive computer graphics system.
GM's first database manager was implemented via linked lists, but in 1977 the "Virtual Associative Access Manager" {VAAM) was developed to use virtual storage and implementing entity relationships as arrays.
APL consists of six statements, CREATE, INSERT, FIND, FOR EACH, REMOVE, and DELETE,[1]: p.85 and miscellaneous functions such as counting the number of members in a set, determining the length or type of an entity, or locating an entity by name.
[1]: p.95 APL statements were implemented as PL/I preprocessor macros, which translated into calls to the database manager.
Later GM's Apple PL/I dialect supported APL directly in the language.