mahi328

 Profile Answers by mahi328 Questions by mahi328

• Mar 7th, 2006

 

DML Commands:           Insert,Update,Delete,Merge

DDL Commands:           Create,Alter,Drop,Rename,Truncate

DCL Commands:           Grant,Revoke

TC Commands:             Commit,Rollback,Save point

Anita

• May 25th, 2006

 

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

abc

• Aug 8th, 2006

 

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.

subang

 Profile Answers by subang 

• Jan 16th, 2010

 

What are Primary key and foreign Key?
Primary key: It is a key which is used to avoid the dupilcate and null entries in the database(eg:entering registerno of the students)

What do you know about Triggers?
A trigger is a stored procedure. It is fired automatically when insert,delete or update commands are issued against the table on which trigger is defined.