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

Key Fields in Database Relationships 

In database management, key fields are essential for establishing relationships between different tables. These relationships allow you to combine and retrieve data from multiple tables as if they were a single table.

Types of Key Fields

There are primarily two types of key fields used to establish relationships:

• Primary Key: A field (or combination of fields) that uniquely identifies each record in a table.
• Foreign Key: A field in one table that refers to the primary key in another table. This creates a link between the two tables.

How Relationships are Established

The relationship between tables is established by matching the value of the foreign key in one table with the value of the primary key in another table. This creates a link between related records in the two tables.

Importance of Key Fields

Key fields are crucial for:

• Data Integrity: Ensuring the accuracy and consistency of data across multiple tables.
• Data Retrieval: Efficiently retrieving related data from multiple tables.
• Database Design: Properly structuring the database to support efficient data management.

Conclusion

Therefore, the correct answer, re-iterating the definition of key fields, is Option 4: Key fields are used to establish relationships between tables in a database.

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.