Question

Question 17
In SQL, which of the following statements is false?
Primary key does not allow duplicate values.
In case of foreign key, a child may have duplicate and NULL values.
A table should have only one unique key.
A unique key cannot be of LONG data type.​

Answer 1

Answer:

Explanation:

B

Answer 2

a) Primary key does not allow duplicate values.

b) In the case of the foreign key, a child may have duplicate and NULL values.

c) A table should have only one unique key.

d) A unique key cannot be of a LONG data type.​

Option (c) A table that should have only one unique key is the false statement here.

• A special language is used to manage the data kept in the tables, that language is SQL.
• SQL uses many commands or instructions to access and perform operations on data.
• The key that is used to identify each row in a table is the primary key that does not allow the duplication of values.
• The key in a table used to identify the primary key of another table is the foreign key that allows value duplication.
• The user can't define a LONG data type as the primary key.
• The table can have more than one unique key as the user needs,