Which of the following is true about a primary key?Group of answer choicesIt is not necessary for a primary key to be unique.It must be unique for each record in the table.It can contain NULL values.A table can have multiple primary keys.

Which of the following statements is true about PRIMARY keys and UNIQUE keys?Multiple options may be correctThere can be multiple UNIQUE keys but only one PRIMARY keyOnly the PRIMARY key column gets indexed automaticallyBoth are non-nullable

Which of the following is NOT a characteristic of a primary key?Group of answer choicesNon-nullabilityUniquenessUniquely identifies each record in a tableCan be updated frequently

Which of the following statements is true?Group of answer choicesA composite key cannot be a primary keyEvery candidate key is a super key.An alternate key is a super key with redundant attributes.Every super key is a candidate key.

Which is/are correct statements about primary key of a table?Primary keys can contain NULL valuesPrimary keys cannot contain NULL values.A table can have only one primary key with single or multiple fieldsA table can have multiple primary keys with single or multiple fields

Which of the statement(S) are incorrect w.r.t primary key in SQL. A. A primary key can contain duplicate values to ensure redundancy.B. A primary key can be a composite key, consisting of multiple columns.C. A primary key must be an auto-increment field.D. A primary key cannot be null