Computer Sciene of Udayana State University

April 18, 2009

Record/Tuple

Filed under: Computer Science — ignaga @ 11:45 AM
record

record

In the context of a relational database, a row—also called a record or tuple—represents a single, implicitly structured data item in a table. In simple terms, a database table can be thought of as consisting of rows and columns or fields. 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 would represent a single company. Columns might represent things like company name, company street address, whether the company is publicly held, its VAT number, 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 cents.

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