Need a little help understanding dimension vs. detail, when to use

[Former Member]

I am taking an SAP online Universe Design course (BOU315 Universe Design XI 3.0/3.1) and have been doing basic Universe Design work for about 6 months (along with Web Intelligence reporting).

So I see the definition of each, pros and cons, and basically understand this, but wondering how exactly to implement (and why)

Dimension 

Dimensions are the focus of analysis in a query. A dimension maps to one or more columns or functions in the database that are key to a query. 

Detail 

A detail object provides descriptive data about a dimension. A detail is always attached to a dimension. It maps to one or more columns or functions in the database that provide detailed information related to a dimension. 

We have a student database, so in most Universes, the first class is "Student Info", and below that is the basic student info: student_id, name, phone, email, status, active, grad_year, birth_date, etc. etc.

So as I understand this, I would have Student_ID as the dimension and the other columns in the Student table as details ? Which means that in this class, Student Info, there's only one dimension (Student_Id), and everything else is a detail ? I must be missing something here. Maybe my classes aren't right . . .

In the pros and cons link, it says details can be used in a merged query, which we use every so often.

[amitrathi239 · Accepted solution]

Hi,

Dimension is something like characteristic..Dimension objects typically retrieve character type data  like product,region,date,student name.

Detail are something which is associate with Dimension.Like in your case  Student name is dimension and  age,DOB other details which are related with student  are details objects.

It's more up-to you how are you managing your objects in the universe.There is no harm if you will create  all dimension objects in the universe. only thing is if you are going to create student details as details then it's easy to understand like age/DOB detail objects are related with Student.

Earlier in BO 3.1 you can not merge the detail objects.but now in BI 4.1 you can merge the objects at webi query level if required.Earlier  in BO 3.1 if same requirement come to merge the DOB/address objects then you needs to change the object qulification from Details to Dimension for webi merged dimension.

Amit

[Former Member · Accepted solution]

Amit,

thank you, this helps.

So, generally speaking, it sounds like it depends on how you want to do it. But, for my understanding, if we did Student Name as Dimension, they everything else (in the Student table) is a candidate for a detail ? Something like this:

[amitrathi239 · Accepted solution]

Hi

your assumption is correct.all details are related with student only.

but if your version is BO3.1 and in one report Student ID (Detail object)is  coming from two different webi queries and need to merge the student ID which you can not merge in the BO 3.1.in that case you need to make the student id as a dimension object.

with BO 4.0 you can merge two detailed objects also in webi.

Detail and dimension relationship is  one:one.

Amit