Understanding ER Models

What does ER stand for in ER Model?

• Entity-Relation Model

• Entity-Record Model

• Entity-Reference Model

• Entity-Relationship Model

Define an entity in the context of an ER Model.

• An entity is a diagrammatic representation of data flow.

• An entity is a real-world object or concept in an ER Model.

• An entity is a specific attribute of a real-world object.

• An entity is a type of relationship in an ER Model.

What is an attribute in an ER Model?

• An attribute is a type of relationship between entities.

• An attribute in an ER Model is a property or characteristic of an entity.

• An attribute is a diagrammatic representation of an entity.

• An attribute is a unique identifier for an entity.

How do entities and attributes relate to each other?

• Entities are objects in a database, and attributes are their properties.

• Entities cannot have multiple attributes.

• Entities are the same as attributes.

• Attributes are only used for indexing.

What is a relationship in an ER Model?

• A relationship in an ER Model is a type of entity.

• A relationship in an ER Model is a single attribute.

• A relationship in an ER Model is a method of data storage.

• A relationship in an ER Model is an association between two or more entities.

Give an example of a one-to-many relationship.

• A manager and their team members.

• A teacher and their students.

• An author and their books.

• A parent and their children.

What is a primary key?

• A primary key is a unique identifier for a record in a database table.

• A primary key is a duplicate identifier for records.

• A primary key is a type of foreign key.

• A primary key is an optional field in a database table.

Why are foreign keys important in a database?

• Foreign keys are only necessary for large databases.

• Foreign keys are important because they ensure data integrity and establish relationships between tables in a database.

• Foreign keys are used to speed up database queries.

• Foreign keys can be ignored if primary keys are present.

How do primary keys and foreign keys differ?

• Foreign keys uniquely identify records; primary keys link tables.

• Primary keys are used for indexing; foreign keys are for data validation.

• Primary keys can be null; foreign keys cannot.

• Primary keys uniquely identify records; foreign keys link tables by referencing primary keys.

What role do relationships play in an ER Model?

• Relationships in an ER Model illustrate how entities interact and are associated with one another.

• Relationships represent the physical storage of data.

• Relationships are used to store data in tables.

• Relationships define the attributes of entities.