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.
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.
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.