What is loosen table and link table?

[#1]

What is loosen table and link table?

[#2]

Loosen Table

When data that includes circular references is loaded into QlikView, loosely coupled tables are created automatically, to avoid that the circular references create a loop in the QlikView internal logic.

One or more QlikView internal data tables can be explicitly declared loosely coupled during script execution by using a Loosen Table statement.

The use of one or more Loosen Table statements in the script will make QlikView disregard any setting of tables as loosely coupled made before the script execution.

The syntax is:

Loosen Table tablename [ , tablename2 ...]

Either syntax: Loosen Table and Loosen Tables can be used.

Example:

Tab1:

Select * from Trans;

Loosen table Tab1;

Note!
Should QlikView find circular references in the data structure which cannot be broken by tables declared loosely coupled interactively or explicitly in the script, one or more additional tables will be forced loosely coupled until no circular references remain. When this happens, the Loop Warning dialog, gives a warning.

LinkTable:

http://www.quickqlearqool.nl/?p=910

http://dailyqv.blogspot.com.ar/2012/12/link-tables.html

http://community.qlik.com/docs/DOC-1303

http://www.qliktips.com/2011/05/rules-for-creating-keylink-table-in.html

[vikasmahajan]

Hii,

Anil,

Loosen Table means the table which have no association with other table or dimensions also called as loosely coupled table and link table means table is linked with dimensions I am attaching more about link table have a look. ( Link table is basically used for data modelling)

Hope this help you.

Vikas

[#4]

i can't understand........please to say in easy method

[vikasmahajan]

Loosely Coupled  :

Loose coupling is an approach to interconnecting the components in a system or network  so that those components, also called elements, depend on each other to the least extent practicable. Coupling refers to the degree of direct knowledge that one element has of another.

The goal of a loose coupling architecture is to reduce the risk that a change made within one element will create unanticipated changes within other elements. Limiting interconnections can help isolate problems when things go wrong and simplify testing, maintenance and troubleshooting procedures.

A loosely coupled system can be easily broken down into definable elements. The extent of coupling in a system can be measured by mapping the maximum number of element changes that can occur without adverse effects. Examples of such changes include adding elements, removing elements, renaming elements, reconfiguring elements, modifying internal element characteristics and rearranging the way in which elements are interconnected.

Although loose coupling minimizes unnecessary interaction among system elements, it can create problems when such interaction is desired. For example, in some data-centric systems a high degree of element interdependence is necessary for synchronization in real time.

Link Table :

Link tables are generally used for linking the two table or the fact tables.

Let us go with an example..

As we know that when we are designing the datamodel synthetic keys and circular loop are common.

For fixing this problems we use the link table concept.

You can also use concatenation ,but it always not give the appropiate result.

Concatenation works well enough when we have all the fields same.

With the use of link tables, it’s possible to keep the facttables separated from each other. The advantage of this solution   for choosing this method is to keep the datamodel a logical one.

How To: Prevent Circular Reference in a Qlikview Data Model » Quick – Qlear – Qool

Hope this clear now

Vikas

[vikasmahajan]

Refer this discussion

http://community.qlik.com/message/242848#242848

[vikasmahajan]

Hii

You got IDEA what is loosen table and link table or still you want any assistance

Vikas

[alis2063]

Very very helpful ..

Do you have another document for another concept show case.

Thanks buddy