Table join and look up

[Former Member]

Hi Experts,

I have no clear idea regarding table join and look up. I have alrady read from SDN and have seen some example.

Please write down some simple way. I am very much confused with this. Specially why we are doing look up after join

Thanks

[Former Member · Accepted solution]

Hi,

Join combines information from the records in two tables by using the values in a pair of matching fields to match records

in the two tables.

A lookup is a type of join that uses the value of the primary matching field for each record in a primary table to match the corresponding record with the same value for the lookup matching field in a lookup table, and then u201Clooks upu201D additional information from one or more lookup fields in the lookup table record into the primary table record.

As an example consider three tables A , B and C.

Joins are transitive: if Table A is joined to Table B and

Table B is joined to Table C, Table C is effectively joined to Table A.

The MDM Import Manager automatically detects this condition,

displays u201Ctransitive joinu201D Table C as the child not only of Table B but also of the joined lookup Table B node that is a child of Table A, and allows u201Ctransitive lookupsu201D from Table C into Table A.

Hope this would solve your doubt.

If helpful do reward points!!!!!!!

Regards,

Parul

[Former Member]

Hi,

Table join and lookup concept is used join multiple source tables.

We may get the data from different source files.Doing mapping for every source file

would be time consuming process.To save time we have join and lookup concept

where we can join multiple tables .

Specially why we are doing look up after join

As jitesh said, we can choose the field which you want from the joined table depends

on our requirement using lookup concept.

We may want all the fields or some fields from the joined table so depends on our

requirement lookup concept will be used.

Hope it helps

Cheers

Narendra

[Former Member]

Hi Pappu,

Once you have joined the table it means a link has been established between the two tables and lookup allows you to take the fields from the joined table into the first or main table.It is helpful when you dont want all the fields from the joined table to be the part of joining i.e. say from 100 fields you want to use only 2 fields then with the help of lookup you can select only those two required fields

Regards,

Jitesh Talreja