in a relational schema, each tuple is divided into fields called A. Relations B. Domains C. Queries D. All of the above

The correct answer is: A. Relations

A relation is a table in a relational database. Each row in a relation is called a tuple, and each column in a relation is called an attribute. The attributes of a relation define the schema of the relation.

A domain is a set of values that can be assigned to an attribute. For example, the domain of the attribute “age” might be the set of integers from 0 to 120.

A query is a statement that specifies the data that you want to retrieve from a database. Queries are written in a language called SQL.

Here is a more detailed explanation of each option:

• Option A: Relations. A relation is a table in a relational database. Each row in a relation is called a tuple, and each column in a relation is called an attribute. The attributes of a relation define the schema of the relation.
• Option B: Domains. A domain is a set of values that can be assigned to an attribute. For example, the domain of the attribute “age” might be the set of integers from 0 to 120.
• Option C: Queries. A query is a statement that specifies the data that you want to retrieve from a database. Queries are written in a language called SQL.
• Option D: All of the above. This option is incorrect because it includes options that are not correct.