|4.9 Elementary Method "Data Navigation Modeling" (DNAV)|
Together with the logical database modeling (DB modeling) the method Data Navigation Modeling (DNAV) is used to generate a database management system (DBMS) oriented data structure (see method LOGM - Logical DB Modeling) from an ER - E/R Modeling. Data navigation modeling is indispensable for the generation of efficient hierarchical and network-oriented database structures.
Means of Representation
The results of the Data Navigation Modeling are represented with data navigation diagrams. In this connection, E/R submodels are graphically completed by type and order of the accesses of the relevant applications.
Based on (normalized) E/R models it is analyzed in which order and mode (reading, writing, updating) the data accesses of the relevant applications to the E/R models are realized. Furthermore, frequency and priority of these applications must be analyzed and recorded.
|4.1||SD5.1 - Description of SW Component/ Module/ Database||
In order to generate a database schema for existing or respectively commercially available data base systems the method must be applied together with LOGM - Logical DB Modeling and NORM - Normalization. Parameters referring to the physical storage and available in the database schemas of individual database systems can not be defined with DNAV, LOGM - Logical DB Modeling, and NORM - Normalization alone.
Together with LOGM - Logical DB Modeling and NORM - Normalization, DNAV covers that part in subproduct SW Design (Database).Schema Definition that refers to the DBMS-oriented data structure. The complete schema definition also requires the specification of external keys and indices as well as integrity conditions and possibly also views. Furthermore, DBMS-specific storage parameters and all data elements must be completely defined.
|No.||Interface||Observation||Information in Annex 1|
Data Navigation Modeling is based on E/R models. Data navigation diagrams are generated by means of overlapping E/R diagrams with qualified and quantified access paths.
|4.6 Interface DNAV-ER|
|5.2||DNAV-PCODE||Mode and order of the data accesses defined in the DNAV method have to be adjusted to the operational sequence description in PCODE - Pseudocode.||4.7 Interface DNAV-PCODE|
|GDPA Online Last Updated 01.Jan.2002 Updated by Webmaster Last Revised 01.Jan.2002 Revised by Webmaster|