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Link Table & Concatenation

Hello ,

What are the advantages and disadvantages of Link table and concatenation approach?

7 Replies
Sergey_Shuklin
Valued Contributor

Re: Link Table & Concatenation

Hello!

Here you may find a comparison:
https://www.learnallbi.com/link-table-in-qlikview/
In short words: link table is less memory consuming decision.

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Partner

Re: Link Table & Concatenation

why we should not use concatenate method when we have different granularity between fact tables

Sergey_Shuklin
Valued Contributor

Re: Link Table & Concatenation

Hello!

You may use concatenate for different granularity - it's ok. For instance if you have two same tables - one for months and one for weeks, so you can easily union them. No need to use link table. But, if your tables match only with few fields (customer + country) so the better way is to use a link table with a key.
Partner
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Re: Link Table & Concatenation

Hello,

 


Please add if i miss anything on below

 

Link table

 

Advantages:

Should be useful when we have less number of common dimensions available to form a Key between Fact tables

 

Disadvantage:

Link table may cause performance issue in future due to increase in its size

 

 

Concatenation:

 

Advantages:


Suitable when we have large number of common dimensions between fact tables

 


Disadvantages:

Consume more memory

 

 

Sergey_Shuklin
Valued Contributor

Re: Link Table & Concatenation

Looks like the goal.
One more advantage of concatenation:
You can use it instead of JOINs for avoiding record multiplying (if you get such cases during tables join).
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Partner

Re: Link Table & Concatenation

sorry what you mean by "Looks like the goal" ?

Sergey_Shuklin
Valued Contributor

Re: Link Table & Concatenation

I meant that is your post about adv / disadv both methods is more than correct and complete. So I call it "the goal" 😃