Sorting, grouping and duplicate elimination in the advanced information management prototype

Sorting, duplicate suppression and grouping are important operations in relational database man-agement systems. This paper is devoted to the re-lated language features and their implementation in the Advanced Information Management Prototype AIM-P. The query language HDBL is an SQL-like database language supporting the extended NF* data model. The proposed language extensions follow the classical SQL approach for sorting and duplicate elimination by extending the SFW con-struct with appropriate clauses. For the grouping operation we chose a new syntactical construct be-cause the implicit structure transformation of grouping differs from the sorting and duplicate suppression operations. Finally, the integration into the query evaluation of the AIM prototype is de-scribed. 1