An example of output columns from a Postgres database.

In a relational database, a column is a set of data values of a particular simple type, one value for each row of the database.[1] A column may contain text values, numbers, or even pointers to files in the operating system.[2] Some relational database systems allow columns to contain more complex data types; whole documents, images or even video clips are examples.[3] 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, each row can be interpreted as a relvar, composed of a set of tuples, with each tuple consisting of the relevant column and its value, for example, the tuple ('Address 1', '12345 West Example Street').

FieldEdit

The word 'field' is normally used interchangeably with 'column'.[4] However, database perfectionists tend to favor using 'field' to signify a specific cell of a given row.[citation needed]

See alsoEdit

ReferencesEdit

  1. ^ The term "column" also has equivalent applications in other, more generic contexts. See e.g., Flat file database, Table (information).
  2. ^ "Columnar databases in a big data environment". dummies.com (Big dummies book). Retrieved 2015-11-05.
  3. ^ "What is Database Column? - Definition from Techopedia". Techopedia.com. Retrieved 2015-11-05.
  4. ^ "An introduction to databases". www.ucl.ac.uk. Retrieved 2015-11-05.