Relational Database Management Systems, RDBMS
- First principles formulated by E.F. Codd (IBM) in June 1970.
- All data in tables (2D matrices), having rows and columns.
- The user does not have to deal with the file structure.
- All data management involve operations on the tables:
- Creation of tables.
- Insert data as rows in tables.
- Select rows in tables; complex search criteria possible.
- Update values in rows in tables.
- Delete rows in tables.
- All this done using the standard(ish) Structure Query Language (SQL).
- SQL is declarative: What to do, not how.
- SQL has no control structures (if, when, loops).
- SQL has specific data types:
- Char, Varchar
- Date, time
- CLOB (characer long object): long strings
- BLOB (binary long object): large binary blocks of data (e.g. images)
- A special value NULL to denote the absence of a value.
© 2001 Per Kraulis
$Date: 2001/05/09 09:02:32 $