1. A computer program product, the computer program product comprising: a non-transitory computer readable storage medium having computer readable program code embodied therein, wherein the computer readable program code, when executed by at least one processor of a computer, is configured to perform: retrieving a report specification that includes one or more query declarations of data to be presented and one or more layout declarations describing how the data is to be rendered; retrieving a semantic model with concepts, wherein the semantic model comprises a Web Ontology Language (OWL) model; generating a Business Intelligence (BI) metadata model by executing transformations that transform concepts in the semantic model to BI metadata constructs by: constructing a table for each semantic class in the semantic model; constructing a column for each semantic data type property restriction; and constructing a relationship for each semantic object property restriction; receiving a request for a combined report that combines result sets from the semantic model and one or more relational data sources comprising relational databases; constructing one or more first queries using the BI metadata model and the one or more query declarations; executing the one or more first queries on the semantic model to obtain one or more semantic result sets; executing one or more second queries against one or more relational data sources to obtain one or more relational data source result sets; combining the one or more semantic result sets and the one or more relational data source result sets to construct one or more combined result sets; and rendering the one or more combined result sets to form a combined report based on the one or more layout declarations.
1. A computer program product, the computer program product comprising: a non-transitory computer readable storage medium having computer readable program code embodied therein, wherein the computer readable program code, when executed by at least one processor of a computer, is configured to perform: retrieving a report specification that includes one or more query declarations of data to be presented and one or more layout declarations describing how the data is to be rendered; retrieving a semantic model with concepts, wherein the semantic model comprises a Web Ontology Language (OWL) model; generating a Business Intelligence (BI) metadata model by executing transformations that transform concepts in the semantic model to BI metadata constructs by: constructing a table for each semantic class in the semantic model; constructing a column for each semantic data type property restriction; and constructing a relationship for each semantic object property restriction; receiving a request for a combined report that combines result sets from the semantic model and one or more relational data sources comprising relational databases; constructing one or more first queries using the BI metadata model and the one or more query declarations; executing the one or more first queries on the semantic model to obtain one or more semantic result sets; executing one or more second queries against one or more relational data sources to obtain one or more relational data source result sets; combining the one or more semantic result sets and the one or more relational data source result sets to construct one or more combined result sets; and rendering the one or more combined result sets to form a combined report based on the one or more layout declarations. 3. The computer program product of claim 1 , wherein the computer readable program code, when executed by the at least one processor of the computer, is configured to perform: generating, for the BI metadata model, a graphical representation for each table described in the BI metadata model, wherein each of the graphical representations includes columns for that table, and wherein lines between the graphical representations indicate relationships between the tables.