Related Directory Categories
- Databases (2451)
- Pick (516)
- Data Warehousing (318)
- Oracle (285)
- Data Mining (223)
- Databases and Persistence (166)
- Databases (162)
- FileMaker Pro (144)
- Microsoft Access (114)
- Database Theory (105)
Sources
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
Column (database)
From Wikipedia, the free encyclopedia
In the context of a relational database table, a column is a set of data values of a particular simple type, one for each row of the table.[1] The columns provide the structure according to which the rows are composed.
The term field is often used interchangeably with column, although many consider it more correct to use field (or field value) to refer specifically to the single item that exists at the intersection between one row and one column.
For example, a table that represents companies might have the following columns:
- ID (integer identifier, unique to each row)
- Name (text)
- Address line 1 (text)
- Address line 2 (text)
- City (integer identifier, drawn from a separate table of cities, from which any state or country information would be drawn)
- Postal code (text)
- Industry (integer identifier, drawn from a separate table of industries)
- etc.
Each row would provide a data value for each column and would then be understood as a single structured data value, in this case representing a company. More formally, each row can be 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.
| Row 1 Column 1 | Row 1 Column 2 |
| Row 2 Column 1 | Row 2 Column 2 |
| Row 3 Column 1 | Row 3 Column 2 |
- ^ The term "column" also has equivalent application in other, more generic contexts. See e.g., Flat file database, Table (information).
 |
This database-related article is a stub. You can help Wikipedia by expanding it. |