Mapping is a process which is used in large database warehousing Mapping by which different data models are linked to each other using a defined set of methods to characterize the data in a specific definition. Data Mapping can be applied in several ways using procedural codes, Extensible Style Sheet Language Transformation and other existing graphical interfaces and this technique used evaluating data values in different data sources as well as automatically and simultaneously discovering complex mappings between the sets. Data Mapping is also used to consolidate multiple databases into a single database.