Question

The common fields used in a relationship between tables are called

• A. Joint fields
• B. Main fields
• C. Table fields
• D. Key fields

Answer 1

The Correct Option is D

In a relational database system, key fields are used to establish and identify relationships between different tables. These fields uniquely identify records in a table, and their commonality in two tables forms the basis of the relationship between them.

• Joint fields: are not a standard term used in relational databases.
• Main fields: refer to fields in a table that are important but do not necessarily function as key fields in relationships.
• Table fields: are simply the individual columns in a table and are not specific to relationships.
• Key fields: are the correct term. These fields in one table correspond to the primary key or foreign key fields in another table, allowing the database system to create relationships between them.

Thus, the correct answer is:

(4) Key fields

Answer 2

The Role of Key Fields in Database Management 

Key fields play a fundamental role in database design and management. They are used to uniquely identify records within a table and to establish relationships between different tables.

Here's a breakdown of the key concepts:

• Primary Key: A field (or a combination of fields) that uniquely identifies each record within a table. No two records can have the same primary key value, and the primary key cannot be null (empty). It ensures the integrity of the data within the table.
• Foreign Key: A field in one table that refers to the primary key in another table. It establishes a link or relationship between the two tables. The foreign key enforces referential integrity, meaning that a foreign key value must either match a primary key value in the related table or be null (if allowed).

The use of key fields allows for efficient data retrieval, accurate data updates, and consistent data relationships. Without key fields, it would be difficult to maintain the integrity and reliability of the database.

For example, in an accounting system:

• The Customer ID field in the "Customers" table would be the primary key.
• The Customer ID field in the "Sales Orders" table would be a foreign key, linking each sales order to the corresponding customer in the "Customers" table.

By using these key fields, the system can easily retrieve all sales orders for a specific customer, or retrieve customer information based on a sales order.