Question

To avoid interpreting meaning from Null, we use a:

1) Default constraint
2) Lookup table
3) Flag
4) Check constraint

Answer 1

To avoid ambiguity from Null values in databases, we use a default constraint, which assigns a default value to a column if no value is specified, ensuring data integrity and removing confusion.

Step-by-step explanation:

To avoid interpreting meaning from Null, we use a default constraint. When designing databases, a null value can indicate the absence of data or that the data is not applicable. However, null can sometimes lead to ambiguity, as it's not always clear whether it means data is missing, unknown, or just not yet provided. To avoid such confusion, a default constraint is used in database management systems to assign a default value to a column when no value is specified. This prevents null values from being stored in the database and helps maintain data integrity.

For example, if there is a table for customer information and every customer must have an associated account status, a default constraint could be set on the account status column to automatically assign a default status of 'Active' if none is specified at the time of the customer's entry creation. This ensures that every customer record has a meaningful value for account status.