This window lets you compare two schemas and tells you what has changed from the original reference source to the comparison source. You can use it to compare test and prod schemas, or any other two schemas. The results set is specific to the order you select, so that if you are comparing A to B, the results will be differences in A. You can easily switch these and view the results for B to A.
Switching comparison and reference schemas is performed within memory, so if you have previously run a compare, Toad can switch the schemas for you without querying the database again. Clicking Switch before you have run the comparison will run the comparison.
Right-click in the options tab to check or uncheck all object types.
Use the Object Set tab to select a specific object set to compare.
Results of a compare schema display the changes required to make the second schema look like the reference schema. Therefore, if you reverse the order of the schemas, there may be differences in the number of objects reported as "missing."