1. SQL

          SQL is an English like language consisting of commands to store, retrieve, maintain & regulate access to your database.

2. What does the following query do?

SELECT SAL + NVL(COMM,0) FROM EMP;?

This displays the total salary of all employees. The null values in the commission column will be replaced by 0 and added to salary.

3. What is the value of comm and sal after executing the following query if the initial value of ‘sal’ is 10000
UPDATE EMP SET SAL = SAL + 1000, COMM = SAL*0.1;?

sal = 11000, comm = 1000

4. How will you activate/deactivate integrity constraints?

The integrity constraints can be enabled or disabled by ALTER TABLE ENABLE CONSTRAINT / DISABLE CONSTRAINT.

5. Can a view be updated/inserted/deleted? If Yes - under what conditions?

A View can be updated/deleted/inserted if it has only one base table if the view is based on columns from one or more tables then insert, update and delete is not possible.

6. What does teh term upsizing refer to ?

Applications that have outgrown their environment are re-engineered to run in a larger environment. This is upsizing.

7. In a Client/Server context, what does API (Application Programming Interface) refer to ?

An API, in a Client/Server context, is a specification of a set of functions for communication between the client and the server.

8. What description of a data source is required for ODBC ?

The name of the DBMS, the location of the source and the database dependent information.

9. What is ON DELETE CASCADE?

When ON DELETE CASCADE is specified Oracle maintains referential integrity by automatically removing dependent foreign key values if a referenced primary or unique key value is removed.

10. Why does the following command give a compilation error?

DROP TABLE &TABLE_NAME;

Variable names should start with an alphabet. Here the table name starts with an '&' symbol.