what is link table how it works. and its usage.

[#1]

what is link table how it works. and its usage.

please help me friends

[maxgro]

Link table is used in a data model when you have multiple fact tables to handle. Another way to handle multiple fact table is concatenate, so you can find some post on link table vs concatenate,

Concatenate or Link Table?

Get started with developing qlik datamodels

for link tables you can try here

http://www.analyticsvidhya.com/blog/2014/12/remove-synthetic-key-concatenation-link-table-qlikview/

Qlik Tips: Update to Link Table rules

http://www.learnallbi.com/link-table-in-qlikview/

[#3]

what is link table how it works

[Peter_Cammaert]

Indeed, duplicate of another discussion by the same poster.

[Anonymous]

Hi Babu,

In Data warehousing - Star schema usually have a single Fact in the centre and dimensions surrounding it but sometimes you have a situation where you have more than one Fact table.

In Qlikview,You come across a situation where you have to handle multiple Fact tables, which in turn create synthetic keys or Circular references(Loops).

Link Table is a very useful way to resolve synthetic keys and Circular references(Loops) when multiple fact tables are present in the data model.

Link table is used, when the granularity of the facts tables are different and when they are joined to different dimensions.

To resolve these synthetic keys Link table:

• You should always load Distinct records while creating Link table. Also if the Key field/composite field contains several individual fields then it is good to create Key field
• Create a composite key. Using Auto number ( ) function like:
• AutoNumber(YEAR&’|'&CUSTOMER_KEY&’|'&PRODUCT_KEY) As [%Key field]
• Link table can connect to the original fact tables using this composite Key
• Load all the common fields in one table called Link table
• Drop these fields from the original tables.

Regards

Neetha