9. The system of claim 1 , wherein the similarity module is to determine a value representing the overall similarity by: applying a discount factor to a syntactic similarity based on a number of null values per column of the data; and applying another discount factor to a semantic similarity based a number of classes for a particular column of the data.
1. A data mapping acceleration system comprising: a syntactic profile module, executed by a processor, to generate a syntactic profile of a data source to be mapped; a semantic classification module to generate a semantic classification of the data source by classifying values for a column of data from the data source by using an ontology that includes hierarchal classes, wherein a class of the hierarchal classes includes an attribute of including a lexical realization, and using classes from the ontology for which the lexical realization of the classes matches a column name of the column of the data; and a similarity module to evaluate the syntactic profile and semantic classification to determine an overall similarity between attributes of the data from the data source for mapping the data source.