1. A mapping tool graphical user interface presented on a computer display, comprising: a source screen region that displays a graphical representation of a source object, wherein the source object includes a tree structure comprising at least a source root node, a source record node, and a source field node; a target screen region that displays a graphical representation of a target object, wherein the target object includes a tree structure comprising at least a target root node, a target record node, and a target field node; and a mapping screen region that allows a user to create a mapping between the graphical representation of the source object and the graphical representation of the target object using graphical mapping indicia, the graphical mapping indicia are function objects linking the graphical representation of the target object with the graphical representation of the source object, wherein a runtime engine performs a data transformation between the source object and the target object as a function of the mapping, wherein the source field nodes are indented toward the target field nodes in the mapping screen region in hierarchical fashion from the source record nodes, the target field nodes are indented toward the source field nodes in the mapping screen region in hierarchical fashion from the target record nodes, the source record nodes are indented toward the target record nodes in the mapping screen region in hierarchical fashion from the source root nodes, the target record nodes are indented toward the source record nodes in the mapping screen region in hierarchical fashion from the target root nodes; wherein the graphical user interface is further configured to: replace at least one of the source object or the target object with at least one of a modified source object or a modified target object, respectively; reestablish at least a portion of the mapping associated with at least one of the graphical representation of the source object or the graphical representation of the target object with at least one of a displayed graphical representation of the modified source object or a displayed graphical representation of the modified target object, correspondingly, using node name association based at least in part on a node name of at least one of a modified source field node, a modified source record node, a modified target field node, or a modified target record node, of the at least one of the modified source object or the modified target object, respectively, corresponding to a respective node name of at least one of a source field node, a source record node, a target field node, or a target record node, of the at least one of the source object or the target object, respectively; and display indicia indicating a portion of the mapping associated with at least one of the graphical representation of the source object or the graphical representation of the target object that is not re-established after replacing the at least one of the source object or the target object with the at least one of the modified source object or the modified target object.