Understanding E-R Diagrams

What does E-R stand for in database design?

• Entity-Relation

• Entity-Relationship

• Entity-Reference

• Entity-Record

Define an entity in the context of an E-R diagram.

• An entity is a real-world object or concept represented in an E-R diagram.

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

• An entity is a graphical representation of data flow.

• An entity is a type of relationship in an E-R diagram.

What is the difference between a strong entity and a weak entity?

• A strong entity has a primary key; a weak entity relies on a strong entity and does not have a primary key.

• Both strong and weak entities have primary keys but differ in their attributes.

• A strong entity is dependent on a weak entity; a weak entity is independent.

• A strong entity has no primary key; a weak entity has a primary key.

List three types of attributes in an E-R diagram.

• Key attributes

• Simple attributes, Composite attributes, Derived attributes

• Primary attributes

• Foreign attributes

What is a relationship in an E-R diagram?

• A relationship in an E-R diagram represents a single data point.

• A relationship in an E-R diagram is a type of entity.

• A relationship in an E-R diagram is used to define attributes of an entity.

• A relationship in an E-R diagram shows how entities are connected to each other.

Explain the concept of cardinality in E-R diagrams.

• Cardinality refers to the color coding of entities in E-R diagrams.

• Cardinality indicates the size of the database in E-R diagrams.

• Cardinality is the process of normalizing data in E-R diagrams.

• Cardinality specifies the number of instances of one entity that can or must be associated with instances of another entity in E-R diagrams.

What does participation mean in the context of relationships?

• Participation is about one person making all the decisions.

• Participation means ignoring each other's needs.

• Participation refers to passive observation in a relationship.

• Participation means active involvement and engagement in the dynamics of a relationship.

How is a one-to-many relationship represented in an E-R diagram?

• A dashed line connecting two entities.

• A solid line with a single arrowhead at one end.

• A line with a triangle at both ends connecting two entities.

• A line with a crow's foot at the 'many' end connecting two entities.

What symbol is used to represent an entity in an E-R diagram?

• Diamond

• Triangle

• Rectangle

• Circle

Describe the notation used for a many-to-many relationship.

• A many-to-many relationship is represented by a junction table and is denoted in ER diagrams with a diamond shape and cardinality indicators.

• A many-to-many relationship uses a one-to-many notation in ER diagrams.

• A many-to-many relationship is denoted in ER diagrams with a circle and no cardinality.

• A many-to-many relationship is represented by a single table with no indicators.