1. A method for viewing mappings between objects, comprising: displaying, using a computer including a processor, on a single screen a navigator view that lists files available at the computer, an outline view that provides textual information about mappings, a properties view that provides information about a currently selected table, and a main view that shows one of an overview that shows mappings between source tables and target tables, a detail view that shows column mappings, and a single mapping group view that shows column mappings, wherein each type of view provides a different amount of detail regarding the mappings, wherein the main view includes a source area, a middle area, and a target area; receiving input selecting the type of view to be displayed in the main view; and in response to receiving the input, creating the selected type of view; and displaying the created view by: in response to receiving the selection of the overview using a pull-down menu, displaying the source tables without displaying source columns, displaying the target tables without displaying the target columns, and displaying the mappings between the source tables and the target tables; in response to receiving the selection of the detail view using the pull-down menu, displaying the source tables and the source columns, displaying the target tables and the target columns, and displaying column mappings between the source columns and the target columns; and in response to receiving selection of the single mapping group view using the pull-down menu, displaying one source table and the source columns of the one source table, displaying one target table and the target columns of the one target table, and displaying column mappings between the source columns of the one source table and the target columns of the one target table.