In a relational database, a row, a.k.a. record or tuple, represents a single, implicitly structured data item in a table. A database table can be thought of as consisting of rows and columns.[1] Each row in a table represents a set of related data, and every row in the table has the same structure.
For example, in a table that represents companies, each row might represent a single company. Columns might represent things like company name, address, etc. In a table that represents the association of employees with departments, each row would associate one employee with one department.
The implicit structure of a row, and the meaning of the data values in a row, requires that the row be understood as providing a succession of data values, one in each column of the table. The row is then interpreted as a relvar composed of a set of tuples, with each tuple consisting of the two items: the name of the relevant column and the value this row provides for that column.
Each column expects a data value of a particular type. For example, one column might require a unique identifier, another might require text representing a person's name, another might require an integer representing hourly pay in dollars.
Column 1 | Column 2 | |
---|---|---|
Row 1 | Row 1, Column 1 | Row 1, Column 2 |
Row 2 | Row 2, Column 1 | Row 2, Column 2 |
Row 3 | Row 3, Column 1 | Row 3, Column 2 |