System(s) and/or method(s) ("tools") are described that enable multiple executable ETL (Extract, Transform, and Load) packages to be built based on a single template. The tools also enable multiple executable ETL packages to be altered by altering a single template and/or set of data parameters. In some embodiments the tools provide many types of templates that are capable, once instantiated with data parameters, of performing many different types of processes useful in extracting, transforming, and/or loading data from databases to a data warehouse. In so doing, the tools can help users to more easily, accurately, and/or robustly build ETL packages.