MCQ IN COMPUTER SCIENCE & ENGINEERING

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COMPUTER SCIENCE AND ENGINEERING

SQL

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
In relational data model, the total number of rows can be identified as ____ .
A
Cardinality
B
Degree
C
Attribute
D
Entity
Explanation: 

Detailed explanation-1: -Cardinality: Total number of rows present in the Table. Column: The column represents the set of values for a specific attribute.

Detailed explanation-2: -The number of rows in the table. The number of unique values for a set of columns for leading columns in an index key, also known as cardinality.

Detailed explanation-3: -The cardinality of a relationship is the number of related rows for each of the two objects in the relationship. The rows are related by the expression of the relationship; this expression usually refers to the primary and foreign keys of the underlying tables.

Detailed explanation-4: -In summary, the three cardinalities (the one-to-one, one-to-many, and many-to-many relationships) are fundamental to describing the relationships between different objects or entities.

Detailed explanation-5: -Or we can say that the cardinality of a relationship is the number of tuples (rows) in a relationship. Types of cardinality in between tables are: one-to-one. one-to-many.

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