ER diagram notation in DBMS Theory - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Identify the symbol for a weak entity in an ER diagram

In an ER diagram, which symbol correctly represents a weak entity?

A A rectangle with a double border

B A diamond with a dashed border

C An oval with a double border

D A rectangle with a single border

💡 Hint

Weak entities are shown differently from regular entities by using a special border style.

In ER diagrams, a weak entity is represented by a rectangle with a double border to distinguish it from a regular entity, which uses a single border.

📋 Factual

intermediate

Meaning of a diamond shape in ER diagrams

What does a diamond shape represent in an ER diagram?

A A primary key

B An entity set

C An attribute of an entity

D A relationship between entities

💡 Hint

Think about how entities connect in a database model.

The diamond shape in an ER diagram represents a relationship between two or more entities.

🔍 Analysis

advanced

Determine the cardinality from ER diagram notation

In an ER diagram, if a relationship line connects to an entity with a crow's foot and a single line, what does this cardinality indicate?

A One-to-one relationship

B Many-to-many relationship

C One-to-many relationship

D Zero-to-one relationship

💡 Hint

Crow's foot notation usually indicates 'many'.

The crow's foot symbol represents 'many', and a single line represents 'one'. Together, they indicate a one-to-many relationship.

❓ Comparison

advanced

Difference between total and partial participation in ER diagrams

Which notation correctly shows total participation of an entity in a relationship?

A A double line connecting the entity to the relationship

B A single line connecting the entity to the relationship

C A dashed line connecting the entity to the relationship

D A dotted line connecting the entity to the relationship

💡 Hint

Total participation means every entity instance must be involved in the relationship.

Total participation is shown by a double line connecting the entity to the relationship, indicating all instances participate.

❓ Reasoning

expert

Identify the error in this ER diagram notation for a multivalued attribute

Which option correctly represents a multivalued attribute in an ER diagram?

A An oval with a dashed border

B An oval with a double border

C A diamond with a double border

D A rectangle with a double border

💡 Hint

Multivalued attributes are shown differently from single-valued attributes by border style.

Multivalued attributes are represented by ovals with double borders in ER diagrams.