Main Page | See live article | Alphabetical index In mathematics, a relation is a generalization of arithmetic relations such as "=" and "<" which occur in statements such as "5 < 6" or "2+2 = 4". See mathematical relation, binary relation and relational algebra. A relational database stores data in relations called tables. Their data manipulation languages provide operations on tables that follow the relational algebra. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.