Database [3i Infotech Placement]: Sample Questions 149 - 150 of 294
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Question 149
Statement True-False▾
It is very difficult to grant and manage common privileges needed by different groups of database users using the roles.
Choices
Choice (4) | |
---|---|
a. | False |
b. | True |
c. | None of the above |
d. | All of the above |
Answer
a.Explanation
- 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
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.