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    Question

    What is the primary purpose of an Entity-Relationship

    (ER) Diagram in database design?
    A To represent the flow of data within an application. Correct Answer Incorrect Answer
    B To model the relationships and attributes of entities within a database. Correct Answer Incorrect Answer
    C To illustrate the SQL queries used to retrieve data. Correct Answer Incorrect Answer
    D To display the physical structure of the database tables. Correct Answer Incorrect Answer
    E To determine the indexing strategy for optimizing performance. Correct Answer Incorrect Answer

    Solution

    An Entity-Relationship (ER) Diagram is a graphical representation of entities, their attributes, and relationships in a database. It serves as a blueprint for database design, helping developers and stakeholders visualize how data is structured and connected. Key components include:

    • Entities : Represent real-world objects or concepts (e.g., Customer, Order).
    • Attributes : Properties or details about an entity (e.g., CustomerName, OrderDate).
    • Relationships : Connections between entities (e.g., Customer places Order).
    For instance, in an online retail database, an ER diagram might show the Customer entity with attributes like CustomerID and Name, linked to the Order entity by a one-to-many relationship. This ensures clarity during database development and helps identify constraints like primary and foreign keys. Explanation of Incorrect Options: A) To represent the flow of data within an application : This describes a data flow diagram (DFD) , which focuses on processes and data movement, not the structure and relationships of database elements. C) To illustrate the SQL queries used to retrieve data : ER diagrams do not include SQL syntax or query logic. They represent static data models, not dynamic query processes. D) To display the physical structure of the database tables : ER diagrams depict logical data relationships, not the physical schema of tables and indexes. Physical design is a later phase of database development. E) To determine the indexing strategy for optimizing performance : Indexing strategies are implementation details unrelated to the conceptual model represented in ER diagrams.

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