Abstract
There are several diagram methods for data modeling like a class diagram. It is very hard to describe a big data model of a large enterprise system into one diagram. It is necessary how to keep consistency among data models. We introduce algebraic structure for syntactical and semantical merger operations on class diagrams and the consolidation condition. We also show associative law and commutative law of the syntactical and semantical merger operations for the class diagram algebra that keeps avoiding inconsistency depending on order of merging.
