If your data uses dates as part of Oracle or Informix database keys, the dates cannot be written as NULL or illegal values. In order to write data that include NULL or illegal values, Acu4GL converts the NULL or illegal date values used in keys to a value of "01/01/01" when writing data to Oracle. Unfortunately, the code would not make a similar conversion when reading the same record, and those records written with "01/01/01" were not found. This would easily result in writing a record that can not be read or deleted. When the 4GL-CONVERT-DATES variable is set to the default setting "CONVERTED", Acu4GL is able to locate and return those records written using the date "01/01/01". This functionality can be disabled by setting the variable to "UNCHANGED."