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What is the purpose of the normalization technique in the data modeling process?

QUESTION:

What is the purpose of the normalization technique in the data modeling process?

 

SOLUTION

 

The purpose of the normalization technique is the systematic validation of the participation of attributes in a relation schema from a perspective of data redundancy.

What is the purpose of the cross-referencing design?

QUESTION:

What is the purpose of the cross-referencing design?

 

SOLUTION

 

The cross-referencing design is an alternative modeling approach that guarantees the absence of null values in the foreign key. It entails the creation of a relation schema to represent the relationship type.

What is the difference between the referencing relation schema and the referenced relation schema? How are these terms incorporated into the foreign key design?

QUESTION:

What is the difference between the referencing relation schema and the referenced relation schema? How are these terms incorporated into the foreign key design?

 

SOLUTION

 

The parent is the referenced relation schema and the child is the referencing relation schema (i.e., it references the relation schema that contains the primary key).

What would cause a relational schema for a database to contain more relation schemas than there are entity types?

QUESTION:

What would cause a relational schema for a database to contain more relation schemas than there are entity types?

 

SOLUTION

 

This is somewhat of a trick question. A relational schema has the same number of relation schemas as there are entity types as long as the Fine-granular Design-Specific ER diagram serves as input.

What is a primary key? How do the properties of a primary key differ from those of a candidate key?

QUESTION:

What is a primary key? How do the properties of a primary key differ from those of a candidate key?

 

SOLUTION

 

A primary key is a candidate key that in addition to having the uniqueness and irreducibility properties also satisfies the entity integrity constraint (i.e., a primary key cannot have a missing value).

What is a candidate key? How does a candidate key differ from a superkey?

QUESTION:

What is a candidate key? How does a candidate key differ from a superkey?

 

SOLUTION

 

A candidate key is defined as a superkey with no proper subsets that are superkeys. A candidate key has two properties: the uniqueness property and the irreducibility property, whereas a superkey possesses only the uniqueness property.

What is the difference between a derived attribute and a stored attribute in terms of their representation in a relation schema?

QUESTION:

What is the difference between a derived attribute and a stored attribute in terms of their representation in a relation schema?

 

SOLUTION

 

Only stored attributes are captured in a relation schema.