Question

When users enter data into the database, they find they have to enter a value for every column, as the database won't allow them to continue otherwise. What type of value has been disallowed for this database?

A. Duplicate
B. Tab Key
C. 0
D. NULL

Answer 1

D. NULL

Step-by-step explanation:

When users find that they have to enter a value for every column in the database and the database won't allow them to continue otherwise, this means that the database has disallowed the use of NULL values.

NULL is a special marker used in SQL to indicate that a data value does not exist in the database. It's used to represent missing or unknown data. When a field is set to not allow NULL values, it means that a value must be entered for that field every time a new row is added to the table