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Many to Many Or not?

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Many to Many Or not? Empty Many to Many Or not?

Post  kali786 Thu Jul 05, 2012 10:37 am

I am junior BI Developer here is the link which i opened I am in a confusion after couple of replies
On Expert said it is many to many one said it is not here is the link to follow
Normally in this case one patient should have many diagnosis and one diagnosis may be given to multiple patients. So you end-up with many-to-many relations.

In your case, you have many to many relationships.


Nope, this what you are describing is not a case of many to many as you have the diagnosis recorder on each activity row so you can model it as a normal regular relationship.

However, as patients in fact do have several diagnosis this may indicate a problem in your fact table.


Hrvoje Piasevoli


MDX with Microsoft SQL Server 2008 R2 Analysis Services Cookbook by Tomislav Piasevoli

Hi HrvojePiasevoli ,

So this is not a Many to many relation thanks for your reply then what is many to many relationship I am a junior in DW modelling as of internet and books for example a author can write many books and one book can have many authors ,

a class can have many students and one student can be in many class,

what in my case one patient can have many diagnosis ,

one diagnosis can have many patients not to sure whether this is many to many ?

select PK_AEDiagnosisMF,AEDiagnosisMF_Code,PatientID,AttendanceDate
inner join
where PatientID=100015Results are

ID Dia_code P_ID Date

17 CF 100015 2005-03-27 19:36
18 CHI 100015 2006-10-19 18:52
19 CN 100015 2010-10-19 14:01
20 CO 100015 2011-08-09 08:22

select top 5 PK_AEDiagnosisMF,AEDiagnosisMF_Code,PatientID,AttendanceDate
inner join
where AEDiagnosisMF_Code='CF'Result is

Here diagnosis Code CF has different patients is this not a many to many relation can you please explain why I coudnt bring my head around so confusing as this relates to the examples above book and authors,class room and students etc..

17 CF 100004 2011-09-24 13:25
17 CF 100038 2006-11-04 00:56
17 CF 10008 2011-12-19 16:31
17 CF 10011 2008-08-04 09:35
17 CF 100116 2006-11-20 15:12

cany any one suggest what relation is this


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Join date : 2012-07-05

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