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Legacy Business Intelligence => COGNOS Impromptu => Topic started by: murali on 22 Nov 2005 07:00:13 PM

Title: wht is meant by weitage of a table
Post by: murali on 22 Nov 2005 07:00:13 PM
Hi all,

can anybody tell me wht is the weightage of table or why this is used and is there any default value for this weightage.


thanks
murali
Title: Re: wht is meant by weitage of a table
Post by: MFGF on 23 Nov 2005 04:14:51 AM
Hi Murali,

I don't believe 'Weightage of tables' exists in the ReportNet environment.Ã,  I'm guessing you are referring to Table Weighting, which can be specified within an Impromptu catalog?

If that's the case, table weighting in Impromptu is used to determine the order of precedence for tables in the 'From' clause of the SQL queries generated by Impromptu.Ã,  Tables with lower weighting values come before tables with higher weighting values.Ã,  The default weight assigned to each table by Impromptu is 5.Ã,  For example, if your report spans two tables - A and B - and A has a weighting value of 5, while B has a weighting value of 3, the SQL query for the report would be

SELECT <list of columns>
FROM B, A
WHERE <joining and filtering clauses>

Weighting can also be used to dictate the preferred join paths between two tables where a loop exists in the join strategy.Ã,  Eg A joins to B which joins to C. Also A joins to D which joins to E which joins to C.Ã,  Impromptu will use the join path with the lowest total weighting value (ie if all tables have a weight of 5, A-B-C totals 15, A-D-E-C totals 20, so A-B-C would be used).

If this is what you are looking for, please could you move this topic to the Impromptu forum.Ã,  Alternatively, If this is not what you meant, please provide some more details and we will try to help you further.

Best regards,

MF.
Title: Re: wht is meant by weitage of a table
Post by: chaithu1108 on 24 Apr 2006 06:30:16 AM
hi,

Ã,  weightage is used for enhancing the performance.the tables with less no. of records are assigned less weightage.so that they are retrived first from the database.the default weight is 5.the table with less weightage immediatly follows the FROM clause in the sql query