Link Table creation: use concatenate or outer join?

[jim_chan]

hi guys,

i am creating a link table.... i see alot of articles when guiding on creating linktable , it uses Concatenate..

but, actually can we just Outer Join instead of Concatenate??? what is the difference? i really need some help to differentiate it to apply in the link table....

rgds

jim

[marcus_sommer]

A link-table contains usually the key-values of several tables within a single key-field and this will be reached by concatenating these values repectively tables and not by adding further fields. I think there are not many scenarios in which a join approach might be useful to create a link-table.

Beside this you should rather avoid link-tables because they are often not necessary and have in regard to the needed efforts and performance disadvantages against a (official recommended) star-scheme datamodel.

- Marcus