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In relational database terminology, which term corresponds to one row of a table (relation)?

  1. ATuple
  2. BAttribute
  3. CDomain
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Answer: A. Tuple

A relational database represents data as tables (relations) made of rows and columns, and relates tables to each other through values. In the terminology of the relational model, one row of a table is a tuple, one column is an attribute, and the set of values an attribute may take is its domain. In an employee table, for example, the row holding one employee's data is a tuple, columns such as name and department are attributes, and the range of non-negative integers allowed in the age column is a domain. Because the relational model treats a table as a set of rows, the order of rows has no meaning and two completely identical rows are not allowed (in real SQL tables, identical rows can be stored if no primary key is defined).

  • A. Correct. One row of a table is a tuple.
  • B. An attribute is one column of a table, such as name.
  • C. A domain is the set of values an attribute may take.
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