Question

________ helps to enforce integrity and identify relationships among tables in a database.

• A. Row
• B. Tuple
• C. Key
• D. Column

Hint:

Remember that Primary Keys enforce Entity Integrity, while Foreign Keys enforce Referential Integrity between related database tables.
Always identify the operational purpose of keys when linking tables in relational databases.

Answer 1

The Correct Option is C

Concept:
In relational database management systems (RDBMS), maintaining data accuracy, consistency, and establishing meaningful relationships across disparate tables is vital for structural integrity.
Database constraints and relationships are governed primarily by the implementation of keys, which serve as foundational attributes or sets of attributes.

Step 1: Understanding Database Keys and Integrity:
A key in a database relation is an attribute or a combination of attributes that uniquely identifies a record (or tuple) within a table.
Primary keys enforce entity integrity by guaranteeing that each record remains distinct and that no primary key attribute contains a null value.
Foreign keys enforce referential integrity by linking an attribute in a referencing child table to the primary key of a referenced parent table.
This mechanism establishes valid logical relationships between tables, ensuring that references cannot point to non-existent data.

Step 2: Analysis of Incorrect Options:
A row or tuple represents an individual record of data containing specific values for each attribute.
Rows or tuples do not define rules, relationships, or structural integrity constraints between tables.
A column represents a single vertical attribute or field across all tuples and merely stores data of a uniform type.
Neither rows nor columns by themselves enforce relational dependencies or constraints without an associated key specification.
Final Answer:
Therefore, a Key is specifically used to enforce integrity and identify relationships between tables.