Interview Questions

Oracle constraints are used to maintain consistent of data and ensure the data is properly maintained. A constraint is more or less a restriction we try to apply on a table.
Types of constraints:
- Check constraints
- NOT NULL constraint
- PRIMARY KEY constraint
- REFERENCES constraint
- UNIQUE constraint

Client code must use setters and getters to access internal data in DataHiding

1. A fixed budget is established for a specific level of activity whereas flexible budget is prepared for various levels of activity.

2. Fixed budget cannot be changed after the period commences, whereas a flexible budget can be changed after the period commence.

3. Fixed budget is more suitable for fixed expenses whereas flexible budget takes both fixed as well as variable expenses in account.

4. Fixed budget includes only fixed costs, whereas a flexible budget includes fixed costs, variable costs and semi variable costs.

5. Fixed budget is mainly used in planning stage whereas flexible budget is used in controlling stage.

PL/SQL exceptions are raised using the RAISE command. This command is used when exceptions are defined by programmer and not implicit exceptions.

Example:

Declare and raising an exception:

DECLARE

short_of_attendance EXCEPTION;

min_attendance NUMBER(4);

BEGIN

...

IF min_attendance < 10 THEN

RAISE short_of_attendance;

END IF;

EXCEPTION

WHEN short_of_attendance THEN

-- handle the error

END;

DB2 precompiler (if embedded sql used), CICS translator (if CICS program), COBOL compiler, Link editor. If DB2 program, create plan by binding the DBRMs.

A constructor is a member function of a class that is used to create objects of that class. It has the same name as the class itself, has no return type, and is invoked using the new operator. We cannot invoke a constructor directly.

A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator.