_______ indicates the maximum number of entities that can be involved in a relationship.a)Greater Entity Countb)Minimum cardinalityc)Maximum cardinalityd)ERDCorrect answer is option 'C'. Can you explain this answer?

Question

Answer

The term cardinality refers to the uniqueness of data values included in a single column (attribute) of a table in SQL (Structured Query Language).

Answer

Explanation:

In a relational database, the maximum number of entities that can be involved in a relationship is referred to as the maximum cardinality. It specifies the upper limit on the number of instances of one entity that can be associated with a single instance of another entity through a relationship.

Cardinality in Relationships:

In database design, cardinality refers to the relationship between two entities. It describes how many instances of one entity can be related to how many instances of another entity. Cardinality is usually represented using minimum and maximum values.

Minimum Cardinality:

Minimum cardinality represents the minimum number of instances of one entity that must be associated with instances of another entity. It specifies the lower limit on the number of instances required for a valid relationship.

Maximum Cardinality:

Maximum cardinality represents the maximum number of instances of one entity that can be associated with instances of another entity. It specifies the upper limit on the number of instances allowed in a relationship.

Example:

Let's consider a simple example of a relationship between two entities: 'Students' and 'Courses'. The relationship between them is 'Enrollment'.

The minimum cardinality of the 'Enrollment' relationship might be 0, indicating that a student does not have to be enrolled in any course.

The maximum cardinality of the 'Enrollment' relationship might be 5, indicating that a student can be enrolled in up to 5 courses.

Conclusion:

The maximum cardinality indicates the maximum number of entities that can be involved in a relationship. It helps define the upper limit on the number of instances of one entity that can be associated with a single instance of another entity.

Similar Computer Science Engineering (CSE) Doubts

In an ER model, suppose relation R is a 1 : M relationship from entity set Y to entity set X. Assume that X has participated totally and Y has participated partially in R and that the cardinality of X is greater than the cardinality of Y.Which of the following option is/are true?

In an Entity-Relationship (ER) model, suppose R is a many-to-one relationship from entity set E1 to entity set E2. Assume that E1 and E2 participate totally in R and that the cardinality of E1 is greater that the cardinality of E2. Which one of the following is true about R?

In an Entity-Relationship (ER) model, suppose R is a many-to-one relationship from entity set E1 to entity set E2. Assume that E1 and E2 participate totally in R and that the cardinality of E1 is greater that the cardinality of E2. Which one of the following is true about R?

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