If you save data after changing variable or observation properties, then the changes are saved as well. Most variable properties (for example, formats) are saved with the SAS data set, whereas observation properties (for example, marker shapes) are saved in a separate metadata file. The metadata file is stored on the client PC and has the same name as the data set, but with a dmm extension.
For example, if you save a data set named MyData to your PC, then a file named MyData.dmm is also created in the same Windows folder as the MyData.sas7bdat file.
If you have changed the data and try to exit SAS/IML Studio, you are prompted to save the data set if you have done any of the following actions:
edited cells in the data table
changed a variable’s properties (name, label, format, informat)
changed a variable’s measure level (nominal, interval)
sorted a data set
added or deleted a variable
included or excluded observations
changed an observation’s marker properties (shape, color)
added or deleted an observation