Need help in understanding the join mechanism

zulfi123786 · Post by **zulfi123786** » Mon Sep 28, 2009 2:27 am

What happens when a join is performed on pair of keys which donot have the same metadata, i think for a join to be performed only the column name should be the same and the metadata of the keys can be different. For Example a join is performed on column "KEY" which is char 10 in left link and char 20 in right link, does DS perform implicit conversion from char 10 to char 20 so that the join can be performed??? if yes does it pad spaces??? what happens when char is joined with decimal???

ArndW · Post by **ArndW** » Mon Sep 28, 2009 2:38 am

DataStage will do an implicit conversion, but it is much better to ensure that the metadata is identical and do an explicit conversion. Char() field conversion are always blank padded. I don't know the rule for conversion, perhaps DS uses the left link as the original and converts the other links to match that datatype.