Star Schema and Oracle 11gR2 ?

Star Schema and Oracle 11gR2 ?
I know the star schema (ROLAP) and implemented couple of them. Apart from general design principle of dimension, FACT, surrogate key etc, what are the specific items needed in Oracle 11gR2?
Some one talked about over 10 conditions/pre-requisits for Star Schema (ROLAP) implementations in Oracle 11gR2. I did some search, but I did not get any hits.
Do we design Star schema (ROLAP) differently in Oracle 11gR2?
Any pointer welcome.
Thanks in helping.

Hi,
from my experience there are no specific requirements for the star schema design when using owb 11.2.
When using the OWB ETL Option (extra license required), one may use the owb dimensions and cubes.
These make mapping development easier, since support for SCD2 is built into the dimension operators. Loading the cube is simplified because the lookup of the surrogate key from the dimension is built into the cube operator.
These owb objects will deploy specific dimension and fact tables. If you already have existing ones, you must modify them manually.
I implemented several projects without these advanced features. Baiscally I did the same in OWB what I would have done using hand-coded SQL and PL/SQL. And it worked just fine.
If you find those 10 conditions, please post them here. I'm curious to learn about them!
Regards,
Carsten.

Similar Messages

Star Schema and Cubes

Hi,
I'm learning the basic concept of data warehousing and I've some question in this regards.
1) I want to know, are we have to first create star schema and tables according to that star schema in dbms, from that star schema we have to built cubes OR we directly build cubes from extracted data through OLTP systems.
2) secondly, when we create cubes, in which formate they are store in dbms and are they directly load in the memory at run time?
Please clarify me in these concepts as new to data warehouse I've certain concept misunderstanding in this regards. Answers will be highly appreciated
Regards,
D.Abbasi

1) I want to know, are we have to first create star schema and tables according to that star schema in dbms, from that star schema we have to built cubes OR we directly build cubes from extracted data through OLTP systems. Star schema is the Dimensional Modeling Technique and that need to considered while creating Dimension and not cubes.
So you need to create first design your database either in Start schema or Snow flag and then need to create dimension tables and after wards Cubes.
2) secondly, when we create cubes, in which format they are store in dbms and are they directly load in the memory at run time?Cubes and Dimensions are stored in Database in some different format.
This is the nice article regarding how the data is store in DB,
http://www.dba-oracle.com/t_olap_dimensions_cubes.htm
Cheers
Nawneet
Edited by: Nawneet on Mar 29, 2010 5:47 AM
Edited by: Nawneet on Mar 29, 2010 5:50 AM

How to document your star-schemas and dashboards?

Hello practitioners,
We are new to OBIEE and started some weeks ago. We are a two-men team. One guy doing all the data design and the other for everything around Answers.
So it happens regularly that the other guy has to ask the one guy, about the exact definition and meaning of data-fields, he wants to use in Answers.
Being a real programmer the one guy only needs a proper, self-explainary field name as documentation, of course (or so he thought).
Question:
What tools and methods do you use to document the star-schemas and dashboards?
Being the other guy, it is important, that I pick the correct fields, while on the other hand I do not want to disect a dashboard I built a while back, everytime somebody wants something simular, just to figure out what I actually did, back then...
Thank you for your help
Turalf
Edited by: Turalf on Mar 24, 2010 12:03 PM

Hi Turalf,
Have you looked at the OBIEE Metadata Dictionary ? A method to allow answers users to gain access to column definitions, and you can view the mapping from Presentation, through BMM to Physical layer.
Im pretty sure you can expose comments from the RPD into this also.
http://obiee101.blogspot.com/2008/12/obiee-metadata-dictionary.html
Maybe you could look at the ODI - OBIEE data lineage also, it provides "report to source" mapping info :
http://www.oracle.com/technology/obe/fusion_middleware/ODI/OBI-ODI_Lineage/OBI-ODI_Lineage.htm
Hope this helps.

How you we design and create a star schema in Oracle BI?

We can use Informatica to generate ETL. But how do we design the star-schema?? Is there a design tool like Oracle Designer??
What is the purpose of the DAC??

Hi,
You can handle the star schema design in the BMM layer. No separate tool for that.
Refer-
http://gerardnico.com/wiki/data_modeling/star_schema
DAC-
Data Warehouse Application Console (DAC) works together with Informatica to acomplish the ETL for pre-packaged BI application.
- DAC publish the changes from OLTP
- Informatica extracts the changes from the change log published by DAC as well as from the base table
- Informatica load the data to the stage tables and the target tables in the data warehouse
- DAC manage the performance by dropping indexes, truncating stage tables, rebuilding the indexes, and analyzing the tables during the process
If you do not use DAC, you have to write your own custom change capture process and need to redesign from scratch an ETL method that allow the restart of the ETL process from point of failure at record level. The biggest saving is that DAC can survive during the upgrade , while your custom processes cannot.
Refer-
http://obieetraining11.blogspot.in/2012/06/how-to-use-dac-source-system-parameter.html
Hope this helped/ answered.
Regards
MuRam
Edited by: MuRam on Jun 25, 2012 2:37 AM

Audit whole schema objects by multiple users or schemas in oracle 11gR2

OS: LInux
DB: Oracle 11gR2
schema as many tables and DML access given to many user/schemas in oracle db.
AUDIT ALL BY test BY ACCESS; appears to be audit records created only when changes are done using actual owner connection but not grantee..
I need to audit all the test tables DML and DDL performed not just owner but all the grantees (grantees action should be audited only grantee do dml or ddl on test owner tables not his own tables).
Need to audit test owner tables accessed by multiple users DML and DDL actions..
is there any simplest way to do this and can someone please help me out?
thanks.

http://docs.oracle.com/cd/E11882_01/server.112/e26088/statements_4007.htm#i2059073
Please read the passage labeled 'Auditing by clause'. It answers your question.
Kindly consult documentation before asking any question.
Sybrand Bakker
Senior Oracle DBA

Star Schema and MV's

Hi Guys,
I have designed a Star schema for one of my datamart and my client is after me suggesting that over that I should create a MV to provide a consolidated view. I am trying to convience my client not to do so with the points as below:
1.     As we have created a Star Schema in the database we should take advantages of the same and should avoid creating another layer of reporting which in future will increase the complexity of the queries while expanding the functionality of the mart.
2.     We have to create a complete refresh MV and during refresh data will not be available for reporting to users and the duration will increase over the period of time once the data increases
3.     As MV are a table on a disk using a MV in this case will consume the tablespace which will increase over the period of time.
Please can you experts suggest of any more points or additions. We are using SAP BO as a reporting tool in our organization wherein a Universe can be created easily for reporting.
Cheers,
Shaz

I have designed a Star schema for one of my datamart and my client is after me suggesting that over that I should create a MV to provide a consolidated view. I am trying to convience my client not to do so with the points as below:You are convincing them to NOT do one of the the things materialized views were originally introduced to provide?
I'm purposely going all the way back to 8i documentation here to emphasize the point.
http://docs.oracle.com/cd/A87860_01/doc/server.817/a76994/qr.htm#35520
" Overview of Query RewriteOne of the major benefits of creating and maintaining materialized views is the ability to take advantage of query rewrite, which transforms a SQL statement expressed in terms of tables or views into a statement accessing one or more materialized views that are defined on the detail tables. The transformation is transparent to the end user or application, requiring no intervention and no reference to the materialized view in the SQL statement. Because query rewrite is transparent, materialized views can be added or dropped just like indexes without invalidating the SQL in the application code. "
>
The theory behind query rewrite is this: have them build their queries based on your star schema (or you a build a traditional view that does that), then build a materialized view that mirrors the query/view. If the materialized view is refreshing or not up-to-date, their queries will run (more slowly) against the star schema. If it is up-to-date it will be used instead, providing faster results.
But before you go to that trouble: they are asking for a consolidated view (presumably something easier to query - common in data warehousing). You can create a view to provide this. If that view is not fast enough for their performance requirements, materialize it. Yes, the materialized view uses space, but that space is the price you pay for meeting the performance requirement.

Star Schema and EUL

1. It's a prerequisite to use a star schema to build a EUL or I can/ must used a Relational Schema?
2. The OLAP Option of Discoverer Plus work with an EUL or with a star schema
3. Which components requiere the OLAP option that don't require the Relational Option (i.e. AW) ?
4 I can generate a star schema as: a) a simple relational model where the FK key is a common domain for the fact and dimension table (i.e. Dept. Number) and having a table for each dimension (I don't speaking about time dimensions, but fields like barnch, dept., etc,). b) a star schema where the dimensions are grouped in tables depending on its significance (i.e. Producto, Channels, Time, etc). In this case I'll use a auto-generated sequential number as key for each table record, wich is referenced in the fact table. The question is, which is, in general, the best strategy 1.a ot 1.b. It depends of the size of the database?
5. There is two bussines areas wich need the same information, but one of them, will used always a summarized version whit 60000 records (the other one will process more than 1000000 each time). No doubts in using two distincts set of tables to generate two distincts EULs or Star Schemas, in order to gain in performance?

This is a more suitable question for the Business Intelligence (EBS).
In the mean time, you may want to check the BI OBE: http://www.oracle.com/technology/obe/obe_bi/bi.html , as well as http://www.oracle.com/technology/products/bi/index.html, http://www.oracle.com/technology/documentation/bi_doc.html
~ Madrid.

Using two facts of two different star schemas and conformed dimensions

Hi,
I've been working as developer and database designer for years and I'm new to Business Objects. Some people says you can not use two facts of two different star schemas in the same query because of conformed dimensions and loop problems in BO.
For example I have a CUSTOMER_SALE_fACT table containing customer_id and date_id as FK, and some other business metrics about sales. And there is another fact table CUSTOMER_CAMPAIGN_FACT which also contains customer_id and date_id as FK, and some other business metrics about customer campaigns. SO I have two stars like below:
DIM_TIME -- SALE_FACT -- DIM_CUSTOMER
DIM_TIME -- CAMPAIGN_FACT -- DIM_CUSTOMER
Business metrics are loaded into fact tables and facts can be used together along conformed dimensions . This is one of the fundamentals of the dimensional modeling. Is it really impossible to use SALE_FACT and CAMPAIGN_FACT together? If the answer is No, what is the solution?
Saying "you cannot do that because of loops" is very interesting.
Thank you..

When you join two facts together with a common dimension you have created what is called a "chasm trap" which leads to invalid results because of the way SQL is processed. The query rows are first retrieved and then aggregated. Since sales fact and campaign fact have no direct relationship, the rows coming from either side can end up as a product join.
Suppose a customer has 3 sales fact rows and 2 campaign fact rows. The result set will have six rows before any aggregation is performed. That would mean that sales measures are doubled and campaign measures are tripled.
You can report on them together, using multiple SQL passes, but you can't query them together. Does that distinction make sense?

Star schema and Infoprovider

Hello,
maybe this question is strange but is it necessary to create for each Infoprovider / Infocube one star schema?
Thanks in advance

Hi
I t is imperative that you refer some documentation related to BI Modeling. There are a couple of good docs. available which explain in detail about building an Infocube based on star schema to meet certain reporting requirement.
From your statement, it is clear that you still need to get a better of understanding of the modeling. Instead refer to the link below. It's a fantastic document.
http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/6ce7b0a4-0b01-0010-52ac-a6e813c35a84
Cheers
Umesh

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

Capture-schema and Oracle

I am trying to run capture-schema on command line with Oracle and am getting the following error:
java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getConnection(DriverManager.java 532)
I have set the CLASSPATH to /u01/app/oracle/8.1.7/jdbc/lib/classes12.zip
Running utility as:
./capture-schema -dburl jdbc:oracle:thin:@boxname:1521:sid -username myname -password mypassword -driver oracle.jdbc.driver.OracleDriver -schemaname SchemaName -table MyTable -out /usr/tmp/File.dbschema
I know it is picking up the Oracle in classpath since if I remove the classes12.zip It complains that it can't find the oracle.jdbc.driver.OracleDriver.
Anyone know what I'm missing here?

Hi, I have captured the schema file and stored it at mytest.dbschema in the src directory for my classes. I can see that the file is a part of the ejb.jar file and the sun-cmp-mappings.xml file the schema is defined as "mytest".
When I try to deploy the jar file, I get an error stating the following:[05/Oct/2004:15:45:52] SEVERE ( 412): JDOCodeGenerator: Caught a RuntimeException :
java.lang.RuntimeException: Could not find schema file mytest on classpath EJB CL:
[com.iplanet.ias.loader.EJBClassLoader$URLEntry@1d626a4, com.iplanet.ias.loader.EJBClassLoader$URLEntry@82f392]
Does anyone have any idea where I am supposed to put that file and also to which classpath is the compiler is refering? I assumed that since it is a part of the ejb.jar file, I would not have to specify a path to the file.
Thanks,
WPM

ORA-01017: OS Authentication on Red Hat Linux 6.2 and Oracle 11gR2

Hello
I am trying to eanble OS Authentication on Oracle 11.2.0.3 installed on a Red Hat Linux Server 6.2 and it just does not work. When I try to login I always get the error ORA-01017: invalid username/password; logon denied
I have set the following Oracle parameters:
remote_os_authent = TRUE
os_authent_prefix = OPS$
and i have created a linux user "oracle" and the Oracle user "OPS$oracle".
I know that the parameter remote_os_authent in 11g is depricated but i thought that it still should work, just an error messages occures then i start the database but it runs as usual, just the OS Authentication does not seem to work.
Does anyone knwo where the problem could be?
Oracle said that remote_os_authent is depricated because as it is risky, i know that, but my database is in a secure environment without any connection to the internet. What other way would there be without using remote_os_authent?
Thank you very much for your help.
Regards Bernhard

Thanks for the link, i found that i used a case sensitive user name as i created the user with "OPS$USERNAME" and this was why i cound not connect with that user.

Dimensions and facts related to all BI Apps Financials Star Schemas

I am kind of new to BI Apps and was wondering whether there is a list of tables/dimension names/ facts that constitute each star schema in Financial Analytics?
I know there are star schemas like AP Aging, AR Aging, AP Transactions, AR Transactions and so on.
How do I get the OBAW dimension and fact table names that are in each of these star schemas?
Oracle BI Apps presentations take me only to the business name of the dimensions and does not give me the original dimension name used in OBAW.
Thanks in advance!

Hi Sid
I am in Data Model Reference that you have mentioned. All the star schemas over here are pictures and are not searchable. Also, the ppt that Oracle gave us just says AP Aging as the fact name and I dont know how I can find the fact table corresponding to that.
If someone can point me for that piece of work, I will go though the star schema pictures in the documentation and find relevant dimensions and facts.
Is there any naming convention that we can use like W_APAging_F table or something like that??
Thanks in advance !
Edited by: user566193 on Jan 21, 2010 2:43 PM

Newbie question : why is star schema fast and efficient?

Hi all,
just a stupid question, but I haven't been able to find a proper
answer so far...
Why is star schema a good design for Data Marts and DWH?
What is the underlying reason that makes it attractive
performance wise?
Why wouldn't just one big table with all the data in it and with
the proper indexes be enough?
Thanks all!!
Regards
Vincent

There are several reasons to use star schemas, particularly in
Oracle.
A flat table like you asked about looks attractive but has
several flaws, i.e. massive data redundancy, no logical
groupings, no aggregation (or additional redundant data
aggregated), etc.
A start schema is semi-denormalized to allow easy reporting. A
truely normalized system is diffucult to report against be cause
you may have to join many tables to return just 2 pieces of
related data. A star schema enables you to join to only a single
dimension table to the fact table to return the same 2 pieces of
data. If you're returning many pieces of data, a star schema
keeps access very simple. Most third party reporting tools
recognize star schemas and will build your where clauses behind
the scenes making them a lot more useful to end users.
Oracle is adding optimizations to the cbo for start schemas.
Using dimensions, materialized views, partitions, IOTs, etc
greatly enhances performance for queries against massive amounts
of data. It does make loading the data more difficult but the
trade off at query time is worth it.
A flat table structure, besides having a lot of redundant data,
is hard to optimize. When you have terebytes of data, a flat
table structure gets scary even with indexes.
This is just my opinion, hope that helps.
Lewis

Star schema of Datawarehouse

Hi,
I'm working with BI Apps (OBIEE) uploaded on PeopleSoft HCM 9.1 source system. I'm using pre built ETL task to load the pre designed Datawarehouse.I want to know where can I found the Datawarehouse star schema description?

What you are looking for the DMR (Datawarehouse Model Reference) Doc. I believe they have this on Metalink for the BI Apps releases. This provides the physcial star schemas and details on the DW tables. Here is the metalink note:
Oracle Business Analytics Warehouse Data Model Reference Version 7.9.6, 7.9.6.1 and 7.9.6.2 [ID 819373.1
If this was helpful, please mark the response as correct.

Star Schema and Oracle 11gR2 ?

Similar Messages

Maybe you are looking for