Schema matching

The terms schema matching and <a href="/facts/Data_mapping/1kTMajeS">mapping</a> are often used interchangeably for a <a href="/facts/Database/VYcpkevb">database</a> process. For this article, we differentiate the two as follows: <a href="/facts/Database_schema/DBq8fooY">schema</a> matching is the process of identifying that two objects are <a href="/facts/Semantic/1L4WwLAP">semantically</a> related (scope of this article) while mapping refers to the <a href="/facts/Data_transformation/gjQCKFIa">transformations</a> between the objects. For example, in the two schemas DB1.Student (Name, SSN, Level, Major, Marks)
and DB2.Grad-Student (Name, ID, Major, Grades); possible matches would be: DB1.Student ≈ DB2.Grad-Student; DB1.SSN = DB2.ID etc. and possible transformations or mappings would be: DB1.Marks to DB2.Grades (100–90 A; 90–80 B: etc.).
Automating these two approaches has been one of the fundamental tasks of <a href="/facts/Data_integration/BU47JR28">data integration</a>. In general, it is not possible to determine fully automatically the different correspondences between two schemas — primarily because of the differing and often not explicated or documented semantics of the two schemas.

Schema matching open-in-new

Schema matching