Solution

The correct answer is By enforcing rules defined in the schema

Key Points

• Data Integrity: In a relational database, data integrity refers to the accuracy, consistency, and reliability of the data stored.
• Schema Rules: The schema defines the structure of the database, including:
  • Data Types: Ensures that only the appropriate data types are stored in each column.
  • Constraints: Rules such as primary keys, foreign keys, unique constraints, and check constraints are enforced to maintain data integrity. For example:
    • Primary Keys: Ensure that each record is unique.
    • Foreign Keys: Maintain referential integrity between tables by ensuring that relationships between tables remain consistent.
    • Not Null Constraints: Ensure that certain fields must contain a value.
• By enforcing these rules, a relational database helps prevent invalid data entry and maintains the integrity of the relationships between tables.

Additional Information

• By encrypting all data stored: Encryption is primarily a security measure, not a direct method for ensuring data integrity.
• By compressing data for efficient storage: Compression is related to storage efficiency, not data integrity.
• By allowing unrestricted access to all users: Unrestricted access would compromise data integrity, as it could lead to unauthorized modifications.