Presentation on theme: "Introducing DB-123 A New Approach to Database Management Systems Thomas Schneider February 2004."— Presentation transcript:
Introducing DB-123 A New Approach to Database Management Systems Thomas Schneider February 2004
Goals Upwards compatible database management ·Minimize costs for migrations ·Maximize security for users ·Do not loose already existing Meta-Information like Hierarchies, Repetitions, …
a practical example – the Donauland Database… consider the following structures … 29DL/I Databases with 75 DL/I Segments and 10 permanent VSAM KSDS Files 6 permanent VSAM ESDS Files 10 SQL-Tables which have to be migrated to a different Operating System and a different Database Management System
a practical example – the Donauland Database… A classical Database-Migration of the described Databases to another System would imply : 55 Download-Programs necessary 95 DB2-LOAD-Files !!! without regarding the problems of Data Integrity as well as 600+ Application Programs to be adapted ….
DL/I --> DB2 Migration A classical Database-Migration to another System would imply : 75 new DB2-Tables necessary only for DL/I Migration (excluding VSAM-Files) !!! all 75 DB2-Tables have to be downloaded from the HOST and uploaded to the new system at once.!
DB123 – the DL/I DB2 Migration-Tool Performs the Database DESIGN automatically manual adaption of DESIGN possible automatic insertion of new fields possible – for instance USER-ID and UPDATE-Date in all new tables
generates DOWNLOAD Programs [COBOL SOURCE and VSE JCL!] for unloading the DL/I databases performs rigorous checks of all values – check NUMERIC fields for valid entries – check all DATE-fields for valid Dates > SQL NULL > SQL NULL – Character-Fields: no imbedded quotes allowed DB123 – the DL/I DB2 Migration-Tool 
DB123 – the DL/I DB2 Migration-Tool  generates COBOL HOST-Variables for SQL-interface automatic update of the old DL/I record COPY-books …add parent keys, USER-ID, LAST- UPDATE, …
DB123 – the DL/I DB2 Migration-Tool  generates COBOL procedures (inline code) for the varios access methods: –xxxGET - for keyed access (unique key given) –xxxNEXT - for SQL Cursor access (alle seq.) –xxxNWP - next within parent [Cursor defined by logical parent] –xxxISRT - for INSERTs –xxxDELE - for DELETEs (with given key) –xxxUPDT - for Updates
DB123: the advantages Take again the Donauland example – for 95 DB2-Tables in the Application There are 95 * 6 = 570 subroutines/procedures which have NOT to be developed manually and tested, but are generated automatically !
DB-123 DESIGN: The DB2-Data-Base Designer for each DL/I Segment and each VSAM KSDS-File a DB2-Table has to be created following the rules of the 3rd Normal Form The rules of the 3rd Normal Form are very simple – read on …
DB-123 DESIGN: The First Normal Form All parent DL/I primary keys must be added to the child records (in front of the existing fields) All unique DL/I primary keys become primary keys of the DB2-table as well.
DB-123 DESIGN: the Second Normal Form If the key is still not unique, a sequence field (trigger) or a so called TIMESTAMP is added Each DB2 table has now a unique key !
Is the DESIGN now complete ? NO ! The DL/I Databases may contain OCCURS-items in the COBOL record structures!
Is the DESIGN now complete ? …continued Cobol-OCCURS-items are NOT supported by DB2! Solution with DB123 : either new, higher level TABLES (DB2DETAIL) or NUMBERING the respective DB2 columns (both Alternatives may be performed automatically, driven by proper clauses in the Data Dictionary).
DB-123 DESIGN: the Third Normal Form All Tables are flat tables (including logical parent keys) Hierarchic relationship retained thru Logical Parent relationships (LPARENT-clause) in data Dictionary.
DB-123 DESIGN: the Third Normal Form Repeated COBOL structures resolved thru DBDETAIL clause in Data Dictionary New Data Dictionary used to GENERATE ACCESS functions and needed COPY- books.
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