Question at position 6 Which statement best describes an Entity–Relationship (ER) data structure?It stores all data in a single flat file with no relationships between recordsIt uses nodes and edges to represent everything as a graph that can be walkedIt represents information purely as documents with no explicit structureIt is made up of tables linked using keys, with data joined together when needed by the systemClear my selection

Question

Question at position 6 Which statement best describes an Entity–Relationship (ER) data structure?It stores all data in a single flat file with no relationships between recordsIt uses nodes and edges to represent everything as a graph that can be walkedIt represents information purely as documents with no explicit structureIt is made up of tables linked using keys, with data joined together when needed by the systemClear my selection

BlackTom AI · Accepted Answer

An Entity–Relationship (ER) model maps real-world objects (entities) and their associations (relationships) into structured tables with defined attributes and keys. Relevant concepts: entities become tables, attributes become columns, each table has a primary key, relationships are implemented using foreign keys, and data retrieval often uses JOIN operations. ER diagrams are a conceptual design tool for relational databases.

Step-by-step reasoning:
1. Define ER/relational fundamentals: An ER design identifies entities (e.g., Customer, Order), their attributes (CustomerID, Name), and relationships (Customer places Order). In implementation these become relational tables: Customer(CustomerID PK, Name, ...) and Order(OrderID PK, CustomerID FK, Date, ...).
2. Show how linking and joins work: To get all orders with customer names, the system performs a JOIN on Order.CustomerID = Customer.CustomerID. This combines rows from both tables at query time without duplicating data permanently.
3. Connect to the choices: Evaluate each option against the ER/relational model.

Why the correct option is correct:
- "It is made up of tables linked using keys, with data joined together when needed by the system" exactly matches relational/ER principles: tables, primary/foreign keys, and on-demand joins implement relationships and maintain normalized structure.

Why the other options are incorrect:
- "It stores all data in a single flat file..." describes a flat-file model with no relationships or keys, which is not ER.
- "It uses nodes and edges to represent everything as a graph..." describes graph databases (e.g., Neo4j), not the tabular ER/relational approach.
- "It represents information purely as documents with no explicit structure" describes document stores (e.g., MongoDB), which emphasize documents over normalized tables.

Conclusion: The correct answer is "It is made up of tables linked using keys, with data joined together when needed by the system," which matches the provided answer.

类似问题

Which of the following best illustrates the relationship between entities and attributes?

Question at position 46 The number of entity types that participate in a relationship is called the: degree.identifying characteristic.number.counter.

Question at position 23 The most common types of entities are:strong entities.associative entities.super entities.weak entities.

Which statement about participation constraints is MOST accurate?

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