Database [3i Infotech Placement]: Sample Questions 149 - 150 of 294

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Question 149

Database
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Statement

True-False▾

It is very difficult to grant and manage common privileges needed by different groups of database users using the roles.

Answer

FALSE

Explanation

Define User System Privileges
  • Oracles allows controlling privileges to users using roles.
  • Grant system privileges to roles- then use the roles to manage system privileges.
    • Privileges grant access to perform a particular action or to perform an action on any schema objects of a particular type.
    • Ex. , the privileges to create table spaces and to delete the rows of any table in a database are system privileges.
    • When multiple users access database objects, authorization can be controlled to these objects with privileges.
  • A user can modify an object owned by another user.

Question 150

Database

Question

MCQ▾

Why is it better to use an INTEGRITY CONSTRAINT to validate data in a table than to use a STORED PROCEDURE?

Choices

Choice (4)

a.

Because a stored procedure creates more network traffic than a integrity constraint definition

b.

Because an integrity constraint is automatically checked while data is inserted into or updated in a table while a stored procedure has to be specifically invoked

c.

Because the stored procedure occupies more space in the database than a integrity constraint definition

d.

All of the above

Answer

b.

Explanation

  • Automatically checked when a data is inserted or updated in a table while a stored procedure was specifically invoked.
  • To define certain data quality requirements in the database.

Basically 5 types of integrity constrain in oracle

  • Not null
    • A column in a table specified not null.
    • it՚s not possible to insert a null in a column.
    • The default is null.
  • Unique key
    • A primary key combines of a unique key and a not null constraint
  • Primary key
    • A primary key combines of a unique key and a not null constraint.
  • Foreign key
    • A foreign key constraint on a column ensures that the value in that column is found in the primary key of another table.
  • Check
    • A check constraint allows stating a minimum requirement for the value in a column.
5 Types of Integrity Constrain in Oracle

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