Hi all, I have been give a database but I unfortunately cannot modify the existing structure of the tables ( order from above ). we have to capture additional information that relates to an existing table. The system already has structures that look like entity attribute value tables. Reading various posts these are said to be not ideal. Therefore I was wondering if there is an alternative to them
depends on whether the additional information can be generalized into consistent groups. if yes, you could add a attribute table having various columns. If they cant be generalised you need an extended table with EAV type values.
Can you add new tables? If so then just create a new table with the additional columns and a PK that links it back to the one it relates to. (I think this is what Visakh said).
Another option is to have an XML structure instead of EAV. That allows a certain amount of flexibility and query options. Personally I prefer it to EAV if I really, truly cannot put the correct columns in the correct tables.
Dumb rule though - your business changes but your systems cannot?!? How's that going to end?