Presentation materials from the October 2008 UNITE Conference in Orlando, Florida.
DMSQL Query Capabilities and Performance (MCP-4032/4033)
The SQL Query Processor (DMSQL) is one of the most interesting MCP data base developments to be released in several years. DMSQL provides a relational front end for query and update of DMSII data bases.
Accessing a data base through a set-oriented relational interface is a lot different than through the traditional record-oriented DMSII interface supported by COBOL and Algol, however. Thus relational access often requires an entirely different approach to the concept and design of the data retrieval process. Also, there is often more than one way to phrase a retrieval in SQL, and understanding which one will be most efficient typically is not easy.
The speaker will present an introduction to the concepts of set-oriented relational query and the syntax of SQL as implemented by DMSQL. A number of commonly-used SQL formulations and techniques will be presented, along with their performance against a DMSII data base. Some common alternative SQL formulations will be presented and their relative performance discussed. The diagnostic capabilities of DMSQL will be presented and the way in which these can be used to understand how DMSQL executes a query will be discussed. Finally, the implementation and performance of a couple of common data retrieval scenarios using DMSQL will be compared with equivalent implementations using the traditional record-oriented DMSII interface.
|Slides & Notes||Presentation slides and notes as Adobe Acrobat .PDF (378 KB)|
|Resources||The source files used with the DMSQL performance study. All contained in a single ZIP archive file. (308 KB)|
|Paradigm Home||Back to Resources||
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