Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
| Question 705 |
Consider the database table “persons” having Person_ID as the primary key.
what are the violated by the above table?
what are the violated by the above table?
| Relationship integrity | |
| Referential integrity only | |
| Entity and domain integrities | |
| Referential and domain integrities |
Question 705 Explanation:
→ Entity integrity ensures that each row of a table is uniquely identified, so that it can be retrieved separately if necessary. The value set of a primary key is unique; no two values may be the same.
→ The rules of entity integrity state that no primary key can be null and that no change can render the primary key null. These rules guarantee that every row of a table is accessible, whether you’re retrieving data or modifying it. You can retrieve each row separately by specifying the value of a primary key.
→ Domain integrity ensures that all the data items in a column fall within a defined set of valid values. Each column in a table has a defined set of values. When you limit the value assigned to an instance of that column (an attribute), you are enforcing domain integrity.
→ Domain integrity enforcement can be as simple as choosing the correct data type and length for a column.
→ The rules of entity integrity state that no primary key can be null and that no change can render the primary key null. These rules guarantee that every row of a table is accessible, whether you’re retrieving data or modifying it. You can retrieve each row separately by specifying the value of a primary key.
→ Domain integrity ensures that all the data items in a column fall within a defined set of valid values. Each column in a table has a defined set of values. When you limit the value assigned to an instance of that column (an attribute), you are enforcing domain integrity.
→ Domain integrity enforcement can be as simple as choosing the correct data type and length for a column.
Correct Answer: C
Question 705 Explanation:
→ Entity integrity ensures that each row of a table is uniquely identified, so that it can be retrieved separately if necessary. The value set of a primary key is unique; no two values may be the same.
→ The rules of entity integrity state that no primary key can be null and that no change can render the primary key null. These rules guarantee that every row of a table is accessible, whether you’re retrieving data or modifying it. You can retrieve each row separately by specifying the value of a primary key.
→ Domain integrity ensures that all the data items in a column fall within a defined set of valid values. Each column in a table has a defined set of values. When you limit the value assigned to an instance of that column (an attribute), you are enforcing domain integrity.
→ Domain integrity enforcement can be as simple as choosing the correct data type and length for a column.
→ The rules of entity integrity state that no primary key can be null and that no change can render the primary key null. These rules guarantee that every row of a table is accessible, whether you’re retrieving data or modifying it. You can retrieve each row separately by specifying the value of a primary key.
→ Domain integrity ensures that all the data items in a column fall within a defined set of valid values. Each column in a table has a defined set of values. When you limit the value assigned to an instance of that column (an attribute), you are enforcing domain integrity.
→ Domain integrity enforcement can be as simple as choosing the correct data type and length for a column.