1. What are the rules for RDBMS and who developed it? 2. What is waterfall and spiral model? 3. What are Primary key and foreign Key? 4. What are commands in DDL, DML, DCL & TCL? 5. What do you know about Triggers? 6. What is the max. number of triggers for row and column in a table?
Total Answers and Comments: 3
Last Update: August 09, 2006 Asked by: Sanjeev Kumar
Waterfall ModellSingle phases has to be passed throughSequential orderChanges of Requirements are not includedSpiral ModellIterative process several cyclesTries to compensate the disadvantages of the Waterfall ModellPrimary goal is minimization of risks
Primary key is a constraint that uniquely identifies each row in a table. The key can be built on a single column or two or more columns together to identify a row uniquely. Such a column cannot contain a null value.
Foreign key is a key that identifies the table and the column in the parent table. This is a referential integrity constraint made up of a column or columns together to establish a relationship between two tables.
