Reg Snow Flake schema design

Hi Experts,
Can any one post few scenarios regarding Implementation of snow flake schema which can not be converted to star schema in BMM layer for better under standing about schemas. I searched my blogs but i did not found exact answer.
Regards,
Rafi

Rafi,
Check these links
http://iniu.net/content/obiee-define-star-schema-over-snowflake-data-model-data-source
http://www.varanasisaichand.com/2012/05/denormalizing-physical-tables-in-bmm.html
http://majendi.blogspot.com/2009/01/obiee-snowflakes-and-stars-part-3.html
http://blogs.datadirect.com/2012/02/obiee-oracle-business-intelligence-integration-with-salesforce-com-crm-and-database-com-via-odbc.html
In general if you follow the OBI best practices you never get snowflake schema in BMM layer.
If helps pls mark

Similar Messages

Star schema and snow flake schema

can any one tell star schema is better or snow flake schema is better why
thx in advance

Hi,
Difference : http://www.diffen.com/difference/Snowflake_Schema_vs_Star_Schema
When it comes to OBIEE star schema will be easy to configure because it don't involve much tables where as snow flake schema need to denormalize the tables in BMM layer to get the desired model but again it all depends on how your system was designed
HR schema which is more like a snow-flake schema structure
Refer http://www.varanasisaichand.com/2012/05/denormalizing-physical-tables-in-bmm.html
Thanks,
Saichand

Multiple star or snow flake schema for universe

Hi,
I would like to know following things
1. Can we use more than one star or snow flake schema for an universe? and how to do this?
2. Using multiple shemas for one universe is it good practice or not?
Regards,
Manjunath

Manjunath,
This is exactly where BusinessObjects excels.
When dealing with multiple fact tables, you use contexts.
Contexts are very simple to understand and you must take your time to do so if you are going to successfully develop universes based on more than one fact table. No matter what universe you build, the rule for contexts is always the same; there are no different circumstances based on, say, industry.
Each context starts with a base table, typically a fact table, where all its joins are at the many end of the relationship. The joins are then followed out through the joined tables up other joins where they in turn are at the many end, as in a snowflake schema.
For example, consider the very basic schema below:
D1 -< D2 -< F1 >- D3 -< F2 >- D4
There are two tables that only have many joins attached to them - F1 and F2.
Starting with F1, I can move to D2. I can also move from there to D1. In the other direction, I can move from F1 to D3. However, I cannot move from D3 to F2 because the join cardinalities are in the wrong direction. So, I've found all the joins that belong in the first context. They are D1-D2, D2-F1 and F1-D3. By the same process, I will get to the second context containing joins D3-F2 and F2-D4.
It doesn't work well with many-to-many joins, but you really shouldn't be facing these in a well-designed multi-star.
As for one-to-one joins, set the cardinality as one-to-many in the direction that you know the relationship should be in for the ownership to work out correctly..
The process that I've described above is essentially how the Detect Contexts algorithm works.
The only remaining thing for you to read up on is the SQL parameters but essentially you need ot be able to select multiple contexts and generate multiple sql statements for each context. Otherwise, what's the point in defining them?!!
Hope that clears it up for you.
Regards,
Mark

Question for integration star and snow flake schema in data warehouse

Dear Reader,
I facing a problem like that
I have two data warehouse, one use star schema, other use snow flake schema. I would like to integrate both of them into one data warehouse. What is the strategy should these two data warehouse adopt in order to integrate int one data warehouse?
Should I scrap both data warehouse and build a new one instead, or scrap one of them and use the other?
What factors should be considered in order for me to more easily resolve the differences between the two data warehouses.
Please advise. Thank you very much.

Hi Mallis,
This is a very broad question and the answer depends on so many factors. Please go through the following articles to get an
understanding of what the differences are when to use which.
When do you use a star schema and when to use a snowflake schema -
http://www.information-management.com/news/10000243-1.html
Star vs Snowflake Schemas – what’s your belief? –
http://www.networkworld.com/community/blog/star-vs-snowflake-schemas-%E2%80%93-what%E2%80%99s-your-belie
Hope this helps!

Snow flake schema to star schema

Hi Gurus,
I am having a snow flake schema how can i turn it into star schema.
thanks,
kumar

In Obiee You can use multiple table source and join 2 tables abd make as singel table.
EX A->B->C
Now we need to join B,C and call it D. Then A->D is star Schema.
Steps is. Join B and C in the physical layer. join B to A Drop B into the Logical layer, Now Drop C on top od the B.
Table B wil get all the column from C. Here it wont create 2 sources, It will look like single source only.
IN the column mapping you can mpa the column to desired physical table.
Later as usula you can join B and A in logical layer.
Get A and B into presentaion layer.
mak if correct/helpful
fiaz

Snow Flake Schema

anybody give me some knowledge about snow flake schema.
in which type of situations,useually snow flake schema creates in data model.
can you please provide me with example?
Thanks in Advance.

In case of large dimesnsion, we will split them to smaller dimensions, this is to make the table better manageable.
Let's take an example you have a Dimension table which stores the information about the shop details, you may have a seperate dimension table which hold the dempgraphic information of the sales area this provide the logical separation of data.
You have to decide based on your data and requirement whether to go for snowflake or Star.
If you have snowflake defined, will be flattened the same in the logical layer of OBIEE.
Thanks,
Vino

How to make snow flake schema to star in Business layer

i have snow flake data model.
anybody tell me how can i convert that snow flake to star by doing the adding multiple sources to a dimention.
how to do the joins with 2 dimention tables in the business layer

Hi
we can do that for example we have dimension table that connected with another dimension table in physical layer
solution- create one new dimension table in bmm layer and drag the columns from two dimension table which in physical layer and give the join condition it ll work,...
Regards
prabhu haridass

URGENT MODELING SNOW FLAKE SCHEMA

Hi i have 2 fact tables fact1 and fact 2 and four dimension tables D1,D2,D3 ,D4 & D1.1 ,D1.2 the relations in the data model is like this :
NOTE: D1.1 and D1.2 are derived from D1
[( D1.. 1:M..> Fact 1 , D1.. 1:M..> Fact 2 ), (D2.. 1:M..> Fact 1 , D2.. 1:M..> Fact 2 ), ( D3.. 1: M.> Fact 1 , D3.. 1:M..> Fact 2 ),( D4.. 1:M..> Fact 1 , D4 ... 1:M..> Fact 2 )]
Now from D1 there is a child level like this: [D1 --(1:M)..> D1.1 and from D1.1.. 1:M..> D1.2.. 1:M..> D4]
Please help me how to design in physical layer and BMM layer. I will be very glad to you guys this is very urgent requirement.
PS: Deepak Gupta you are very helpful earlier please help me.
Thanks,
ch

They too are snowflake.... but we speak snowflake w.r.t dimension attached to FACT...
Alternate solution, but of the same type..
First of all create aliases for all the Tables in physical layer... but create two aliases for D1 , say D1.A1 & D1.A2
Note: you need to create joins between aliases only, no need of creating joins between original tables ..
In Physical Layer, just have all the joins as Physical Foreign Key Join, just the way you have described, making sure that
D1.A1 is connected only to both the facts aliases...
and
D1.A2 is connected only to D1.1 alias
Drag all the aliases in BMM
Now work with Aliases only in BMM Layer
Here D4 is snowflaked...
So in BMM just bring D4 Alias from Physical Layer and onto it, drop D1.1 alias, D1.2 alias and D1.A2 alias , so that now you have 4 logical table sources under 'Logical Table folder' D4.
This is it....
The Only thing is that you ll have to create two Aliases for D1...
Thanks
Ashish Gupta

Snow flake problem

Hello
whats the procedure to resolve the problem if we are able to only build a snowflake schema
my tables are like this:
fact table: sales
dimesion tables: customers, products, orders
other tables that are connected to dimension tables with primary keys are "countries" is connected to "customers" and orders_inventory is connected to orders
so it is forming a snow flake in physical layer and how to we do make in BMM to form a star schema
if we are dragging columns from countries to customers in BMM, will that work effiecently as expected because as a user i am not able to see the data from both the tables. i am working on SH schema from ORACLE 10g database
thanks
rake

rake,
I suggest you do some reading on dimensional modeling and use aliases and multi-source LTSs
You'd need to model in such a way as to avoid circular joins.

URGENT!!!!! Schema design help

Iam trying to design a schema with ActiveDirectory Application mode with the following requirements:
Profile1: CM_VIEW  view equipment, search equipment
Profile 2: CM_USR  All operations possible by CM_VIEW + create equipment objects, modify inventory, create and modify facilities attributes
Profile 3: CM_FULL  All operations possible by CM_USR + delete equipment , facilities
Profile 4: CM_ADM  All operations possible by CM_FULL + admin privilege for security management
There are a list of user groups. This level is more like a container and no privilege is controlled at this level
User Group1 : Admin
User Group2: Manager
User Group3: Operator
Now this list of User groups can have one or more subgroups. The profiles need to be assigned at this level.
Admin group: Admin1
Manager group: NW Manager , Area1 Manager, Area2 Manager etc�
Operator Group: NW Operator, Area1 Operator, Area2 Operator
There is a single network which is divided into 5 area centers. User groups are given access to the whole network or specific area center.
Whole NW access : Admin1, NW Manager with whatever profiles assigned to them
Area1 access : Area1 Manager, Area1 Operator with whatever profiles assigned to them
As Iam a novice with ADAM, I seek some help to get my schema designed. Iam very confused about
- whether the default AD schema would suffice
- do I need to create my own class
- do I need to add my own attributes to existing classes
- If so, should I consider all the operations defined in the profile as user defined attributes?
I could not get specific information for the stuff Iam searching for and Iam struggling to get the shema designed. It is quite urgent and Any help in this area would be greatly appreciated

There would be several ways to solve this problem.
First of all, the schema. You have threee choices;
1. Extend an existing class.This is when the existing class meets your requirements (searching, differentiation) but needs a few more attributes
2. Derive a new subclass from an existing class. This is when you want to differentiate your class, but inherit features from an existing class.
3. Create a new class, when no existing class meets your requirements
For option 1, best way to do this is create an auxilliary class and add it to the existing class. (Eg. create an auxilliary class called clothing sizes, add attributes height, waist, hat size,shoe size,and then add the class to the existing user class)
For option 2, you may want a class called football player, so you create a new class called footballplayer, derived fromthe existing user class.You may add new attributes such as football team, playing position.
For option 3, you may want to create an entirely newclass to represent a football stadium, with both existing attributes such as address, city and new attributes such as seating capacity
So in your case, users & administrators would normally just be user or inetOrgPerson class objects. Equipment & facilities may require their own classes.
Next thing is to use organisationaUnits (OU's) as the boundaries for delegating administrative permissions. For each area, Area 1, Area 2, ...,Area n, create an organizational unit.
Then you have two methods to enforce role based access control.
The first is to use is to use the Windows security model to enforce the object access.
Create groups to represent CM_VIEW, CM_USR, CM_FULL, CM_ADM roles, perhaps even groups such as Area_1_CM_USR
Then grant the following permissions on the OU.
CM_VIEW - read/list eqpt class objects
CM_USR - read/write/list/create/delete eqpt class objects, read/list/write/create facilities
CM_FULL - read/write/list/create/delete eqpt class objects, read/list/write/create/delete facilities
CM_ADM - full permissions on the OU.
You can either define these ACL's on the OU's so the permissions apply to all objects in the OU, or define them on the schema definitions so that as new objects are instantiated they have the default permissions applied. As you want to differentiate access at the OU level, don't worry about the default schema permissions, just set the ACL's on each OU.
The problem you would have is using Java/JNDI to manage the ACL's (writing the security descriptors on the OU or object classes.).Far easier to use either the WIndows API's, Windows scripting interfaces (ADSI), LDIF files or Windows UI components (ADSIEdit).
You may want to do all the schema extension and ACL's with Windows tools,coz they're easier and use Java/J2EE for your application development.
The second approach is to apply the role based access controls within your application. The security risk with this approach is that it may be possible for someone to subvert the security in your application by accessing the directory directly.

LDAP Schema Designer

I am looking for a kind of LDAP Schema Designer , utility that can check consistency of my schema , detect redundancies ....
Any suggestions?
Thanks

I don't know of any tool like that. The problem is actually not quite that simple, since LDAP does not implement a relational database per se, or have concepts about 1st, 2nd, 3rd, etc normal forms.
If you want me to review and refine your schema for you, then you can hire me as a consultant. I have extensive experience in designing schema and modeling directory objects and DIT.
Click my handle for my email address if interested.
podzap

XML Schema Design question

Hello all,
I am a new to XML Schema design and struggling with designing my first XML Schema. Here is my problem.
I have almost 200 elements in my database which I have to use to design XSDs, I have customer name ( last name, first name, dob etc) and customer address ( office address, home address etc) and at the same time I have other player such as Patient name ( last name, first name, dob etc) and patient address( home address, office address).
And then we have some dollor related data such as patient insurance amount, copay amount , total amount and many more $.
What I wanted to know is that what would be best approach to design a XML schema for such kind of system, should I create one schema (xsd) for all the 200 attributes or I should create seperate schema for customers ( including names and addresses along with other dollor amount data ) and a similar xsd for Patient data. Some of the XML documents which I will create from these schemas would be based on customers and patient information both .
Thank you.
Regards
Suhail Ahmad

It's hard to tell what is the best design. But in order to simplify access to these data through other program APIs such as JAXB, you may start from defining objects such as the schema types/elements for customer, patient and the addresses
Then you can assoicate the related data to these object.

Difference between database design and schema design

Hi i have visited so many database websites and i found so many people saying we can design a data base for you. Is schema designing and database designing is the same. so many palces i find people saying we have to design data base first in order to create a physical databse. so i am little bit confused. are they same? and also what is the difference between data model and schema?

> the definition i found for logical data model, physical data model and the definition you
gave for logical database design, physical database design are the same.
Not correct. The physical design is the implemetation of the logical design. These two designs are at different levels. Also, the logical design will be the same. irrespective of the RDBMS product use.
What is incorrect is a designer/architect designing a logical design specifically for Oracle.. or specifically for SQL-Server. A logical design has nothing to do with the RDBMS product (or h/w platforms. app servers, web severs and operating systems used).
So the logical design will always be the same - it is RDBMS independent.
The physical design is fully dependent on the RDBMS product used. The same logical design will be implemented as different physical designs for Oracle and for SQL-Server.

Schema Design

Hello All,
I couldn't find a better forum to post this but if you know of one, please tell me. I need to design a flexible schema for storing product catalog data. I can see 3 possible approaches although I'm sure there are others. 1) create a very specific relational model that's tightly coupled with the attributes of the products in the catalog 2) create a more generalized model where the attributes of the products are defined as name/value pairs 3) use XMLDB to store the definition of each product in an xml type schema.
The problem with #1 is that it's very inflexible and can become complicated. If we have to add new products to the catalog that have different attributes than what we already store, we'll have to make a schema change. The problem with #2 is the obvious issue with name/value pairs (very large tables, indexing problems, data typing problems, etc). The problem with #3 is that I don't know a lot about it and I'm not sure it makes sense. I'm doing a lot of reading but would like to hear what others have to say about it.
Can anyone offer any advice or point me to a good resource on the subject of designing schemas for this type of data. I'm wondering how places like Amazon and other large e-commerce shops store their product catalog data but haven't found anything to help me.
Thanks,
Mark

my bad I didnt explain that correctly
there is a activity template table and a activity schedule table
a schedule holds many activy schedules, an activity template copies info (name, description, etc) into the activity schedule (that way if the template changes, schedules already made with that activity dont change)
and then each activity schedule has 24 hour values

Reg Structures in Query Designer

Hi,
Can someone explain the following regarding Structures usage in Query Designer
1. Limitations of Structures usage
2. When to use Structures and when not to use them in Query Designer
Thanks in Advance
Regards
AVS Reddy

Hi,
Structures in Query designer are reusable across all the queries for particular info provider once you save in the query designer.
Also check the below links for more info:
http://help.sap.com/saphelp_nw2004s/helpdata/en/b2/e50138fede083de10000009b38f8cf/frameset.htm
http://help.sap.com/saphelp_nw2004s/helpdata/en/b2/e50138fede083de10000009b38f8cf/frameset.htm
http://help.sap.com/saphelp_nw2004s/helpdata/en/b2/e50138fede083de10000009b38f8cf/frameset.htm
Reg
Pra

Reg Snow Flake schema design

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