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In a relational database, a column is a set of data values of a particular type, one value for each row of a table.[1] A column may contain text values, numbers, or even pointers to files in the operating system.[2] Columns typically contain simple types, though some relational database systems allow columns to contain more complex data types, such as whole documents, images, or even video clips.[3][better source needed] A column can also be called an attribute.
Each row would provide a data value for each column and would then be understood as a single structured data value. For example, a database that represents company contact information might have the following columns: ID, Company Name, Address Line 1, Address Line 2, City, and Postal Code. More formally, a row is a tuple containing a specific value for each column,[4] for example: (1234, 'Big Company Inc.', '123 East Example Street', '456 West Example Drive', 'Big City', 98765).