Relational Database and ER Diagrams

What is 1NF in Database Normalization?

• Each attribute must contain only atomic values.

• All attributes must be unique.

• Each attribute must contain multiple values.

• Normalization is not necessary in databases.

Explain the symbols used in ER Diagrams.

• Squares for attributes

• Circles for relationships

• Symbols used in ER Diagrams include rectangles for entities, diamonds for relationships, ovals for attributes, and underlined text for keys.

• Triangles for entities

How is 2NF defined in Database Normalization?

• A relation is in 2NF if it is in 1NF and every non-prime attribute is fully functionally dependent on the primary key.

• 2NF is achieved when all attributes are atomic.

• A relation is in 2NF if it is in 1NF and every non-prime attribute is partially functionally dependent on the primary key.

• 2NF requires that every attribute is dependent on the primary key.

What does Cardinality represent in ER Diagrams?

• Cardinality represents the age of entities in ER Diagrams.

• Cardinality represents the size of entities in ER Diagrams.

• Cardinality represents the color of entities in ER Diagrams.

• Cardinality represents the relationship between entities in ER Diagrams.

Describe the concept of 3NF in Database Normalization.

• 3NF requires all attributes to be dependent on the primary key

• 3NF stands for 3 Non-Factors in database normalization

• A table is in 3NF if it is in 2NF and every non-prime attribute is non-transitively dependent on every candidate key.

• 3NF allows for redundant data storage in tables

What are the different Relationship Types in ER Diagrams?

• One-to-Few (1:F)

• Few-to-One (F:1)

• Few-to-Many (F:N)

• One-to-One (1:1), One-to-Many (1:N), Many-to-One (N:1), Many-to-Many (N:M)

Define BCNF in the context of Database Normalization.

• BCNF ensures that every determinant is a candidate key, meaning no non-prime attribute is dependent on any proper subset of any candidate key.

• BCNF ensures that every determinant is a foreign key

• BCNF permits non-prime attributes to be dependent on proper subsets of candidate keys

• BCNF allows for partial dependency on candidate keys

How does 1NF differ from 2NF?

• 1NF enforces unique column names, while 2NF allows duplicate keys

• 1NF allows repeating groups, while 2NF eliminates partial dependencies

• 1NF requires denormalization, while 2NF promotes normalization

• 1NF focuses on atomic values in a table, while 2NF ensures all non-key attributes are fully functionally dependent on the primary key.

Discuss the importance of Cardinality in designing ER Diagrams.

• Cardinality is important in designing ER Diagrams as it specifies the number of instances of one entity that can be associated with the number of instances of another entity.

• Cardinality only applies to one entity in ER Diagrams

• Cardinality is used to define colors in ER Diagrams

• Cardinality is irrelevant in ER Diagrams

Why is BCNF considered a stricter form of normalization than 3NF?

• BCNF allows partial functional dependencies, unlike 3NF

• BCNF is less concerned with data redundancy compared to 3NF

• BCNF eliminates all types of functional dependencies, including those that are not relevant to the candidate keys, making it stricter than 3NF.

• BCNF does not address key constraints, unlike 3NF