QUEL (Query Language)
QUEL is the query language of a relational database system INGRES (Interactive Graphics and Retrieval System). INGRES is implemented on the UNIX operating system developed at AT & T Bell Telephone Laboratories. The implementation of INGRES is primarily programmed in C, in which UNIX itself is written. The design was motivated by high degree of data independence and the possibility of providing a high level and entirely non - procedural facility for data retrieval, update, access control and support of views.