In relational database terminology, a single record (row) in a table is usually referred to as what?

Introduction / Context:
Relational databases use a precise vocabulary to describe their components. Understanding these basic terms is very important for passing certification examinations and for communicating clearly with other professionals. This question checks your knowledge of the correct term used for a single record or row within a relational table.

Given Data / Assumptions:

• We are working with a relational model of data.
• A table consists of rows and columns.
• A row represents one instance of an entity, such as one student or one order.
• The options list several technical words: relation, attribute, criteria, tuple, and schema.

Concept / Approach:
In the relational model, a table is formally called a relation. Each column of that table is called an attribute, and each row is called a tuple. The term schema usually refers to the overall structure or definition of the database. Criteria is a general English word and is used informally for conditions in queries, but it is not the formal name for a row.

Step-by-Step Solution:
Step 1: Recall that a relation corresponds to a whole table of data in the relational model. Step 2: Remember that an attribute is a named column of that table, such as student_name or total_amount. Step 3: Recognize that each horizontal row in the table that contains the values for one entity instance is called a tuple. Step 4: Note that schema usually means the overall design of the database, not a single row. Step 5: From these definitions, conclude that the correct term for a single record or row is tuple.

Verification / Alternative check:
Many textbooks present the relational model using set theory language. In this view, a relation is a set of tuples, where each tuple is an ordered collection of attribute values. If you think of a table of students, the student table is the relation, each student row is a tuple, and each column such as id or name is an attribute. This alternative perspective confirms that tuple is the correct term.

Why Other Options Are Wrong:
A relation names the whole table, not an individual row. An attribute refers to a column that stores a particular type of data, not an entire record. A criteria is a general term for a condition used in queries and is not a formal structural element of the relational model. A schema describes the structure of tables and relationships in a database, not a single row of data.

Common Pitfalls:
Because many tools and user interfaces use the word record instead of tuple, students sometimes forget the formal term. In an exam environment, it is important to be comfortable translating between user friendly language such as row or record and theoretical language such as tuple. Building this mental mapping helps when reading both documentation and academic material.

Final Answer:
In relational terminology, a single record or row in a table is called a tuple.