Null handling compatibitily

Unofficial Content

If you are converting your Knowledge Base from previous version, is important to look at the followings bugs that were fixed in GeneXus 9.0 and could lead to compatibility problems.

  • Java with DB2 iSeries: If a Date data type attribute had stored an empty date (0001-01-01), the Isnull funtion returned TRUE. More Information in SAC 18815
  • If a record containing Varchar and Long Varchar columns was inserted (using the NEW group or from Transaction form), and those attributes were not referenced in the NEW/TRN and the "Initialize Not Referenced Attributes" = Yes, an empty would be inserted. Nevertheless, for Long Varchar a Null was inserted for all DBMS. In case of Varchar, a blank was inserted for all except for Oracle and Informix, where it got the Null "value" for the former and the expected value(empty string) for Informix. More Information in SAC 18861
  • If a record containing Varchar and Long Varchar columns was asigned the nullvalue funtion (or the empty value) and the "Generate null for nullvalue" = No, an empty would be inserted. However, those attribute got the Null "value" when the DBMS is Oracle. More Information in SAC 17712
  • If a reorganization needed to create a temporary table, when the records were copying from the original table to the auxiliary, the null values got the empty value. More Information in SAC 19010
  • With Oracle, using the null() function in a condition like this: "Where null(Att)" , it would return both, the null and the empty values, when the expected result was just those records with att empty (not null). That has been fixed in GX 9.0. SAC 23235.