The true statement is: "Every candidate key is a super key."

Here's why:

1. A composite key can indeed be a primary key. A composite key is a key that consists of two or more attributes (or columns) that together uniquely identify an entity in a table. When this composite key is used as the primary key, it's known as a composite primary key.

2. Every candidate key is a super key. A candidate key is a minimal set of attributes necessary to identify a tuple uniquely. A super key is a set of attributes within a table that can uniquely identify a row within a table. Therefore, a candidate key is always a super key because it can uniquely identify a row.

3. An alternate key is not a super key with redundant attributes. An alternate key is a key that can be used as the primary key but isn't. It doesn't necessarily have redundant attributes.

4. Not every super key is a candidate key. A super key can have additional attributes that are not necessary for unique identification. If these additional attributes are removed, and the key still uniquely identifies each record, then it becomes a candidate key.

Question

The true statement is: "Every candidate key is a super key."

Here's why:

1. A composite key can indeed be a primary key. A composite key is a key that consists of two or more attributes (or columns) that together uniquely identify an entity in a table. When this composite key is used as the primary key, it's known as a composite primary key.

2. Every candidate key is a super key. A candidate key is a minimal set of attributes necessary to identify a tuple uniquely. A super key is a set of attributes within a table that can uniquely identify a row within a table. Therefore, a candidate key is always a super key because it can uniquely identify a row.

3. An alternate key is not a super key with redundant attributes. An alternate key is a key that can be used as the primary key but isn't. It doesn't necessarily have redundant attributes.

4. Not every super key is a candidate key. A super key can have additional attributes that are not necessary for unique identification. If these additional attributes are removed, and the key still uniquely identifies each record, then it becomes a candidate key.

Knowee AI · Accepted Answer

The true statement is: "Every candidate key is a super key."

Here's why:

1. A composite key can indeed be a primary key. A composite key is a key that consists of two or more attributes (or columns) that together uniquely identify an entity in a table. When this composite key is used as the primary key, it's known as a composite primary key.

2. Every candidate key is a super key. A candidate key is a minimal set of attributes necessary to identify a tuple uniquely. A super key is a set of attributes within a table that can uniquely identify a row within a table. Therefore, a candidate key is always a super key because it can uniquely identify a row.

3. An alternate key is not a super key with redundant attributes. An alternate key is a key that can be used as the primary key but isn't. It doesn't necessarily have redundant attributes.

4. Not every super key is a candidate key. A super key can have additional attributes that are not necessary for unique identification. If these additional attributes are removed, and the key still uniquely identifies each record, then it becomes a candidate key.

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.

Question

Solution

Similar Questions

Upgrade your grade with Knowee