When we think of relationships as attributes, what are the value sets of these attributes

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When we think of relationships as attributes, what are the value sets of these attributes? What class of data models is based on this concept?

The correct answer and explanation is :

Answer:

When we think of relationships as attributes, the value sets of these attributes correspond to sets of entity identifiers (primary keys) from related entities. Essentially, the values of these attributes represent references (foreign keys) to other entities in the database.

The class of data models based on this concept is the Relational Data Model. This model represents relationships between entities by using attributes whose values are foreign keys referencing primary keys in other relations.

Explanation:

The relational data model, introduced by E.F. Codd in 1970, organizes data into tables (relations) where each table consists of rows (tuples) and columns (attributes). Relationships between these tables are established using foreign keys, which act as pointers to primary keys in related tables.

For example, in a customer-order database:

  • The Customer table has attributes like CustomerID, Name, and Email.
  • The Order table has attributes like OrderID, Date, and CustomerID.
  • Here, CustomerID in the Order table is a foreign key referencing CustomerID in the Customer table, establishing a relationship between customers and their orders.

In this context:

  • The value set of CustomerID in the Order table consists of values drawn from the set of CustomerID values in the Customer table.
  • This ensures referential integrity, meaning every order must be linked to a valid customer.

Other data models (e.g., Entity-Relationship (ER) Model) also represent relationships explicitly, but the relational model integrates relationships as attributes within relations.

This model is widely used in relational databases like MySQL, PostgreSQL, and SQL Server, enabling efficient data retrieval and enforcing constraints to maintain data integrity.

Image Representation:

Here is the conceptual diagram illustrating the relational data model, showing the Customers and Orders tables with a foreign key relationship.

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