topic Re: Syn Problem in QlikView

Syn Problem

Mon, 28 Jul 2014 19:01:37 GMT

Hello,

I was wondering ig anyone has an idea on how to eliminate the Syn tables QlikView makes.

My problem is that i have a couple of tables that are catalogs. I have a few of them, but then other tables that some use 1, 2, 3 or until 7 catalog tables. The think is that with that problem, it starts creating like 7 Syn tables.

Is there a way to undo this?

Does the Syn tables affect my design?

Can i just ignore them and keep going?

i need help, and being able to explain why it looks so messy or how to avoid it.

thanks,

Re: Syn Problem

jaimeaguilar — Mon, 28 Jul 2014 19:21:31 GMT

Hi,

In QlikView, tables are associated via the names of the fields. If you have more than 1 field with the same name in 2 different tables, then a Synthetic key will be created (as well as the $Syn table(s)). In this aspect QlikView differs from SQL in the way that tables are related.

There are several ways to avoid or eliminating synthetic keys like using Qualify statement, commenting field on either table involved, creating composite keys, etc.

Depending on your scenario, Synthetic keys may affect or not performance of your app, but in general having a synthetic key would be a result of a poorly designed data model.

For more information, please refer to this post that explains clearly Synthetic Keys,

http://community.qlik.com/blogs/qlikviewdesignblog/2013/04/16/synthetic-keys

regards

Re: Syn Problem

maxgro — Mon, 28 Jul 2014 19:28:40 GMT

if you have "some" time, this is a good post about syn keys

Should We Stop Worrying and Love the Synthetic Key?

Re: Syn Problem

Mon, 28 Jul 2014 19:36:02 GMT

hii

There are three ways to remove synthetic key.

1.Qualify and Unqualify

2.Concatenate

3.Mapping

Qualify function is best method to solve this problem.

Qualify function will rename all the field-names to avoid synthetic key.so you have to unqualify one filed from them.