Computer Science
Assertion. There can be multiple options for choosing a primary key in a data table.
Reason. All attribute combinations inside a data table that contain unique values for each row, are the candidate keys.
Relational Database
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Answer
(a)
Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
Explanation
There can be more than one attribute in a relation possessing the unique identification property. All attribute combinations inside a relation that can serve as a primary key are candidate keys, as they are candidates for the primary key position.
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Related Questions
Assertion. A primary key is used to uniquely identify the rows in a data table.
Reason. A primary key is a field or attribute which has a unique value for each row or tuple.
Assertion. A data table can have only one primary key.
Reason. In a data table, there can be only one attribute/field containing unique values for each row.
Assertion. All types of keys contain unique values for each row.
Reason. A foreign-key attribute of a table is the primary key of another table.
Assertion. The foreign-keys of tables are used to establish relationships with other tables and must be handled carefully.
Reason. Referential integrity is a system of rules that a DBMS uses to ensure that the relationships between tables remain valid and no accidental change or deletion occurs in the related data.