- Describing some common uses of database systems
- Describing how to handle data
- Describing Database systems architecture
- Describing the relational model
- Describing the database systems development lifecycle
How to handle data ?
Limitations of
File-Based Approach
Separation and isolation of data
- Each program maintains its own set of data.
- Users of one program may be unaware of potentially
useful data held by other programs.
Duplication of data
- Same data is held by different programs.
- Wasted space and potentially different values and/or
different formats for the same item.
Limitations of
File-Based Approach
Data dependence
- File structure is defined in the program code.
Incompatible file
formats
- Programs are written in different languages, and so
cannot easily access each other’s files.
Fixed
Queries/Proliferation of application programs
- Programs are written to satisfy particular functions.
- Any new requirement needs a new program.