Data_Dependency_and_Structura_Dependency1 - Database...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Database Systems: Design, Implementation and Management, Rob/Coronel Data Dependency vs. Structural Dependency 1 Q&A Question: I have used your text book starting from the first edition in 1993 when I taught in Syracuse University. Today, one of my students asked me what the difference between data dependence and structural dependence is. I cannot answer this question even after I read the book (p 15.) Please help me on this issue. Answer: Structural dependence is easy to explain, so let’s start with it. If you change the structure of your file – that is, you add a field, delete a field, and so on -- then all the programs that access that file must be changed to reflect the new structure. In short, the data exhibit structural dependence. Our sixth edition text contains several examples of structural dependence, but the COBOL program shown on pages 14- 15 yields the most detailed illustration. Data dependence
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/10/2011 for the course CIS339 NONE taught by Professor None during the Spring '10 term at DeVry Chicago.

Ask a homework question - tutors are online