3i Infotech Placement: Sample Questions 537 - 538 of 1245

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Question 537

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Describe in Detail

Essay▾

What is a class?

Explanation

Understanding of Different Level, Class and Files
  • Class is an object oriented programming concept.
  • Provides user defined data type, which holds data members and member functions.
  • It can accessed and used by creating an instance of that class.
  • A class is like blueprint for an object.
  • For example, consider the class of cars.
  • There may be many cars with different names and brand but all of them will shared common properties like 4 wheels, speed limit, mileage range etc.
  • The member functions determine the behaviour of the class- support operations on data held in the objects of the class.

Definition of a class:

Class class_name

{

Data Member;

Method;

}

Class member:

Data and functions are members.

Question 538

Question

MCQ▾

Which of the following is TRUE for the ENFORCE KEY field

  1. ENFORCE KEY field characteristic indicates the source of the value that SQL ⚹ FORMS uses to populate the field
  2. A field with the ENFORCE KEY characteristic should have the INPUT ALLOWED characteristics turned off

Choices

Choice (4)

a.

Only 2 is TRUE

b.

Only 1 is TRUE

c.

1 and 2 are FALSE

d.

1 and 2 are TRUE

Answer

b.

Explanation

Define Enforcing Key Constrain

ENFORCE KEY field:

  • Is a way to enforce integrity within our oracle database.
  • It a constraint used to enforce a relationship between two tables- the values in the one table must appear in another table.
  • Can be defined in either a CREATE TABLE statement or an ALTER TABLE statement.
  • Indicates the source of the value that SQL ⚹ FORMS uses to populate the field.
  • Field in one table refers to the PRIMARY KEY in another table.
  • Relationships involve a parent table that holds the central data values and a child table with identical values pointing back to its parent.
  • The parent and child tables must use the same storage engine.
  • They must not be temporary tables.

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