Star Schema tables Creation

If I am creating a BI analytical application from sample Sales Hisotory schema's transactional data, what is the first Step I need to do? Should I create a star schema from the transactional tables? If this is correct, What I tool I need to use to create such tables with data? I believe once this is done I can create dimensions , measures and cubes using OWM11g. Some on please help me. I am very very new to OLAP , But has lots of interest in it
Thanks
George

Hi George,
If you are working with 11g - did you install all the latest patches? I strongly recommend applying all available patches when working with 11g. All the information you need is here - http://www.oracle.com/technology/products/bi/olap/collateral/olap_certification.html
As for your question about the criteria for desgining dimension tables, the best advice I can offer is to work with star or snowflake dimensions. You can also see sample schema designs for both at these links
Also, in case you haven't already seen it, there is a good blog posting on working with different kinds of dimensions/hierarchies here - http://oracleolap.blogspot.com/2008/01/olap-workshop-4-managing-different.html
Finally, you might find this [white paper|http://www.oracle.com/technology/products/warehouse/pdf/Benefits%20of%20a%20multi-dimensional%20model.pdf] useful as you say you are new to OLAP
Let me know how you get on
Thanks,
Stuart Bunby
OLAP Blog: http://oracleOLAP.blogspot.com
OLAP Wiki: http://wiki.oracle.com/page/Oracle+OLAP+Option
OLAP on OTN: http://www.oracle.com/technology/products/bi/olap/index.html
DW on OTN : http://www.oracle.com/technology/products/bi/db/11g/index.html

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Error in database parameter for star schema table in RSRV

Hi Experts,
In RSRV, I executed the following checks in my cube and it is showing me the following error:-
1) Check database parameter for star schema table for InfoCube ZMM_MVAL
564971 units missing from fact table /BIC/FZMM_MVAL; see details
Message no. RSRV134
Diagnosis
In the fact table /BIC/FZMM_MVAL records have been found that contain values other than zero for key figures that have units, but that have no value for the unit of the key figure. Since the value of the unit has to correspond to the value of the key figure, this inidicates an error when the data was loaded. The values of the units have not been loaded into BW correctly. Choose Details to display the incorrect records.
2) Consistency of time dimension of InfoCube ZMM_MVAL
/BIC/FZMM_MVAL PARTITIONED 1878 ( 30 - 50 )
Please advise me on this.
Thanks in Advance.
Aparna

As mentioned in the log, check the Unit KFs in your cube and make sure that unit is populated for all such values.
e.g. if Qty is 5 KG, then unit KF will have 5 and unit info object should have KF.
Regards,
Gaurav

Can Oracle 9i enable schema/table creation to be transacted?

If anyone can help with this, that would be much appreciated.
So - the server has disabled autocommit and commits/rollbacks are handled by the application. Even though this is the case, Oracle 9i is not rolling back changes that have (i) created schemas/users and/or (ii) tables.
Worse still, it seems to be performing a partial rollback - some tables in a schema are left with data and others are not.
Now, this may be caused by our server creating tables for indexing while adding data to some existing tables - that is the table definitions have auto-committed the transaction to date, also committing the table insertions/updates.
After some delving, the JDBC driver has the following method: dataDefinitionCausesTransactionCommit - for Pointbase and other databases, this returns false - for Oracle it returns true.
The questions are therefore:
1) Is there a solution with Oracle 9i that enables schema and table creation to be transacted?
2) Does Oracle 10g allow definition clauses to be transacted?

Actually I believe there is a limited way to make DDL statements transaction based via the CREATE SCHEMA command.
From the 9.2 SQL manaul >>
Use the CREATE SCHEMA to create multiple tables and views and perform multiple grants in a single transaction.
To execute a CREATE SCHEMA statement, Oracle executes each included statement. If all statements execute successfully, Oracle commits the transaction. If any statement results in an error, Oracle rolls back all the statements.
<<
This may be of some limited use to you, but your process should probably be changed to track of the DDL and to undo (drop) any created objects if a rollback is issued.
HTH -- Mark D Powel --

Map cloned star schema in same BMM Layer.

I have an ID of a group of companies and STAR SCHEMA related to billing with 8 dimensions. This STAR SCHEMA is loaded exclusively with data coming in EBS.
But, due to the acquisition of another company, today I have the need to load data coming from a legacy system.
To create no impact on existing and ETLs conflict of some code, we decided to clone all the star schema tables and load data from legacy.
To not generate any inconvenience to users, we want these facts and dimensions (which have identical structures) arranged so that they appear unique.
Example:
fact_billing_holding
- dimension_day
- dimension_organization
- dimension_vendor
- dimension_consumer
- dimension_transaction_type
fact_billing_legacy
- dimension_day_legacy
- dimension_organization_legacy
- dimension_vendor_legacy
- dimension_consumer_legacy
- dimension_transaction_type_legacy
But you should see structure like this:
fact_billing_holding
- dimension_day
- dimension_organization
- dimension_vendor
- dimension_consumer
- dimension_transaction_type
How can I implement this solution / problem?

Hi Vjbez1!
All facts and dimensions are identical! But all tables in this schema are duplicated and with different data.
The data is organized like:
dimension_organization
- dky_organization - name_organization
            1               Company X
            2               Company Y
dimension_organization_legacy
- dky_organization - name_organization
           1               Company Z
fact_billing_holding
- dky_day - dky_organization - dky_vendor - dky_consumer - dky_transaction_type - qtd_items
     20130101        1                1            1                 1                 50
     20130101        2                1            1                 1                 70
     20130102        1                1            1                 1                 14
     20130102        2                1            1                 1                 88
     20130103        1                1            1                 1                 22
     20130103        2                1            1                 1                 10
fact_billing_legacy
- dky_day - dky_organization - dky_vendor - dky_consumer - dky_transaction_type - qtd_items
     20130101        1              71           31                 12                88
     20130102        1              71           31                 12                70
     20130103        1              71           31                 12                92
In my analysis I want to see like this:
Organization | Total
Company X    | 86
Company Y    | 168
Company Z    | 250
Fernando.

BMM layer creation (Star Schema Physical Layer) - What to add/not add?

Hi All,
I am just looking for any general feedback on the thought/question below.
I am setting out on creating my first BMM layer and trying to determine what I need to do in this layer that will be different and add value from what I already did in the physical layer. My data model is already defined as a star schema within my data mart source. So in the physical layer I have my facts imported along with the dimensions and I have joined them together as needed. Here is what I think I will setup as I move into the BMM layer:
1. I will add heirarchies as needed to enable drill down within my reports
2. I will need to add my calculations/measures to allow for any type of metric to be returned through a request in Answers
3. I do not see a large need to create logical tables (at least not yet) based on multiple physical source tables as my source is already a star schema and dimensionally modeled. For users that also already source a star schema at the physical layer .. do you find that you do a lot of logical table creation/mapping to add functionality or does your BMM look a lot like you Physical Layer?
Other than steps 1 and 2, I am not really sure how much additional manipulation I might do from the Physical to BMM layer since my Physical is already a star schema. Am I missing anything? Obviously everyone's data model and circumstances are different but I wasn't sure if maybe there were some good thoughts on what I might be missing (if anything)?
One last question .. I am not currently planning to use any aliases at the Physical Layer but I do plan to rename the tables at the presentation layer to be more business verbage like. Why are others using aliases?
Thanks in advance for the help.
K

Alastair, thanks for the advice. I'll definitely keep that in mind as I start to build out the BMM.
One question/issue I just ran into as I was wrapping up my Physical Layer mapping. When I check for global consistency, I am getting an error that is complaining that I have multiple joins defined between the same two tables (which I do). This is because I have the following setup:
TBL_A_FACT
F_ID_HIT
F_HIT_DESC
F_ID_MISSED
F_MISSED_DESC
TBL_B_DIM
F_ID
F_DESC
Table A joins to Table B in two ways:
TBL_A_FACT.F_ID_HIT = TBL_B_DIM.F_ID
TBL_A._FACT.F_ID_MISSED = TBL_B_DIM.F_ID
The F_IDs can be either hit or missed on any given fact record and the total distinct set exist in the dimension.
When I define two foreign key joins in the physical layer based on the relationship above and check Global Consistency, I get an error saying that "TBL_A and TBL_B have multiple joins define. Delete duplicate foreign keys if they exist" and it is listed as an error. I guess this makes sense because when the two tables are used in a request OBIEE would need to know how to join them (using the hit or missed field). What is the best approach for handling this..
- Should I define TBL_A twice in the physical layer as:
TBL_A (Alias TBL_A_HIT)
F_ID_HIT
F_ID_HIT_DESC
TBL_A (Alias TBL_A_MISSED)
F_ID_MISSED
F_ID_MISSED_DESC
Or do something like the above in the BMM layer?
Thanks for the help!
K
And then establish the relationships using these separate tables?

Injecting data into a star schema from a flat staging table

I'm trying to work out a best approach for getting data from a very flat staging table and then loading it into a star schema - I take a row from a table with for example 50 different attributes about a person and then load these into a host of different tables, including linking tables.
One of the attibutes in the staging table will be an instruction to either insert the person and their new data, or update a person and some component of their data or maybe even to terminate a persons records.
I plan to use PL/SQL but I'm not sure on the best approach.
The staging table data will be loaded every 10 minutes and will contain about 300 updates.
I'm not sure if I should just select the staging records into a cursor then insert into the various tables?
Has anyone got any working examples based on a similar experience?
I can provide a working example if required.

The database has some elements that make SQL a tad harder to use?
For example:
CREATE TABLE staging
(person_id NUMBER(10) NOT NULL ,
title VARCHAR2(15) NULL ,
initials VARCHAR2(5) NULL ,
forename VARCHAR2(30) NULL ,
middle_name VARCHAR2(30) NULL ,
surname VARCHAR2(50) NULL,
dial_number VARCHAR2(30) NULL,
Is_Contactable CHAR(1) NULL);
INSERT INTO staging
(person_id, title, initials, forename, middle_name, surname, dial_number)
VALUES ('12345', 'Mr', 'NULL', 'Joe', NULL, 'Bloggs', '0117512345','Y')
CREATE TABLE person
(person_id NUMBER(10) NOT NULL ,
title VARCHAR2(15) NULL ,
initials VARCHAR2(5) NULL ,
forename VARCHAR2(30) NULL ,
middle_name VARCHAR2(30) NULL ,
surname VARCHAR2(50) NULL);
CREATE UNIQUE INDEX XPKPerson ON Person
(Person_ID ASC);
ALTER TABLE Person
ADD CONSTRAINT XPKPerson PRIMARY KEY (Person_ID);
CREATE TABLE person_comm
(person_id NUMBER(10) NOT NULL ,
comm_type_id NUMBER(10) NOT NULL ,
comm_id NUMBER(10) NOT NULL );
CREATE UNIQUE INDEX XPKPerson_Comm ON Person_Comm
(Person_ID ASC,Comm_Type_ID ASC,Comm_ID ASC);
ALTER TABLE Person_Comm
ADD CONSTRAINT XPKPerson_Comm PRIMARY KEY (Person_ID,Comm_Type_ID,Comm_ID);
CREATE TABLE person_comm_preference
(person_id NUMBER(10) NOT NULL ,
comm_type_id NUMBER(10) NOT NULL
Is_Contactable CHAR(1) NULL);
CREATE UNIQUE INDEX XPKPerson_Comm_Preference ON Person_Comm_Preference
(Person_ID ASC,Comm_Type_ID ASC);
ALTER TABLE Person_Comm_Preference
ADD CONSTRAINT XPKPerson_Comm_Preference PRIMARY KEY (Person_ID,Comm_Type_ID);
CREATE TABLE comm_type
comm_type_id NUMBER(10) NOT NULL ,
NAME VARCHAR2(25) NULL ,
description VARCHAR2(100) NULL ,
comm_table_name VARCHAR2(50) NULL);
CREATE UNIQUE INDEX XPKComm_Type ON Comm_Type
(Comm_Type_ID ASC);
ALTER TABLE Comm_Type
ADD CONSTRAINT XPKComm_Type PRIMARY KEY (Comm_Type_ID);
insert into comm_type (comm_type_id, NAME, description, comm_table_name) values ('23456','HOME PHONE','Home Phone Number','PHONE');
CREATE TABLE phone
(phone_id NUMBER(10) NOT NULL ,
dial_number VARCHAR2(30) NULL);
Take the record from Staging then update:
'person'
'Person_Comm_Preference' Based on a comm_type of 'HOME_PHONE'
'person_comm' Derived from 'Person' and 'Person_Comm_Preference'
Then update 'Phone' with the number based on a link derived from 'Phone' which is made up of Person_Comm Primary_Key where 'Comm_ID' (part of that composite key)
relates to the Phone table Primary_Key which is Phone_ID.
Does you head hurt as much as mine?

Resolving loops in a star schema with 5 fact tables and 6 dimension tables

Hello
I have a star schema, ie 5 FACT tables and 7 dimension tables, All fact tables share the same dimension tables, some FACT tables share 3 dimesnsions, while other share 5 dimensions.
I did adopt the best practices, and as recommended in the book, I tried to resolve them using Context, as it is the recommended option to Alias in a star schema setting. The contexts are resolved, but I still have loops. I also cleared the Multiple SQL Statement for each context option, but no luck. I need to get this resoved ASAP

Hi Patil,
It is not clear what exactly is the problem. As a starting point you could set the context up so that it only covers the joins from fact to dimension.
Fact A, joins Dim 1, Dim 2, Dim 3, and Dim 4
Fact B, joins Dim 1, Dim 2, Dim 3, Dim 4 and Dim 5
Fact C, joins Dim 1, Dim 2, Dim 3, Dim 4 and Dim 6
Fact D, joins Dim 1, Dim 2, Dim 3, Dim 4 and Dim 7
Fact E, joins Dim 1, Dim 2, Dim 4 and Dim 6
If each of these are contexts are done and just cover the joins from fact to dim then you should be not get loops.
If you could lay out your joins like above then it may be possible to specify the contexts/aliases that should work.
Regards
Alan

Star schema without a fact table?

Hi,
I'm preparing my warehouse for using with Discoverer and my question is about the star schema.
- Is a star schema directly associated with data warehouse?
- Can I talk about a star schema if a) I do not have a fact table (no summarized values) and b) if I do not have a dimension of time?
The problem is, I'm thinking of usine Discoverer but should I use it if it's not connected to a data warehouse?
As I told, I'd like to modelized my data "like" a star schema but my "center table" will contain only the foreign key of my dimensions; no time dimensions, no aggregate data in the center table (fact table).
Is there another word for the model I'd like to do?
Thank in advance.

Hi,
Is a star schema directly associated with data warehouse?Not really, a star schema is just one where there is one large fact table joined to many smaller dimension tables using key fields. You usually see this in data warehouses.
Can I talk about a star schema if a) I do not have a fact table (no summarized values) and b) if I do not have a dimension of time?A star schema must have a fact table but it doesn't need contain summarised values or a time dimension.
You can use Discoverer with any Oracle database, it doesn't have to be a data warehouse.
Rod West

Star schema cannot be mapped to multiple tables

Hello!
I am mapping dimension in AWM.
When I am drawing lines from the source columns to the target objects "Member". I get the message "star schema cannot be mapped to multiple tables". Sometimes I can workaround the problem by drawing the lines in a different order. But this dose not always work
I have a dimension that have several levels and hierarchy and I always get the message "star schema cannot be mapped to multiple tables" no matter in witch order I draw the lines to "Member".
Why do I get this message and how do I do to solve the problem?
Best regards,
Tina N Mörnstam

Hi Tina:
Is your dimension snowflaked? Are you mapping from more than one source table to the target dimension? Is the hierarchy formed over different tables?
Hazbleydi C. Verástegui

Converting 3 tables to a star schema ??

Hi i was trying to prepare a very small demo for an OLAP system. Anyways I have a simple transaction database for a supposed Book Store anyways the database has the following 3 tables :
Table No:1
Table Name:Main Table
This Table contains the following columns:
Customer Name (PK) | Book Purchase ID (PK) | PRICE
Table No:2
Table Name:Customer Table
This Table contains the following columns:
Customer Name | CELL | ADDRESS
Table No:3
Table Name:BOOKS Table
This Table contains the following columns:
BOOK Name | Book Purchase ID | GENRE
so the above is my transactional database.. LEt me know if i am missing any other detail. Anyways now i want to convert the above to start schema ?? How would i acccomplish that .. I tried to read a couple of tutorials but i was a bit confused... so if you guys could assist me on this i would be really thnakfull.

David_Aldridge wrote:
thinking in general about this, it sounds like what you need is a set of four tables:
Dim_Cust -- stores customer details as a dimension
Dim_Book -- stores book details as a dimension
Dim_Date -- stores dates for transactions
Fct_Book_Sales -- stores the transactions themselves as the purchase of a book for a certain price by a customer on a date.
Use synthetic keys for all but the Dim_Date.Okay i kind of got lost on the way here is wht i know so far regarding the star schema
"A star schema consists of fact tables and dimension tables. Fact tables contain the quantitative or factual data about a business--the information being queried. This information is often numerical, additive measurements and can consist of many columns and millions or billions of rows. Dimension tables are usually smaller and hold descriptive data that reflects the dimensions, or attributes, of a business. SQL queries then use joins between fact and dimension tables and constraints on the data to return selected information."
so from your explaination there are going to be 3 dimension tables
Dim_Cust (Details about the customers) (Customer_ID,Cell No,Address)
Dim_Book(Details about the Books) (Book Name ,ID,Genre)
Dates (I am confused about the dates part)
Fct_Book_Sales (Confused about this part also)
and one last thing What would the fact table look like ??

Creation of star schema from snowflake schem in BMM layer

hi,
This is my situation.I have "Fact-table" which has Dim 1 .now Dim 1 is joined to Dim2,Dim3
Fact
|
Dim 1
|
| |
Dim 2 Dim 3
Now in Bmm Layer how can i make this snowfalke schema to star schema.I heard about making changes in the Logical Table source.And what will be the look of the presentation layer.
Any help is appricaited Guys.

In physical layer, you have a join between Dim 1 and Dim 2, Dim1 and DIm3, Fact and Dim1. In BMM for Dim1, in the sources, add Dim2 and Dim3. You may add both these dimensions in one single LTS if the data is not duplicate in the tables. In case the data is duplicated add them as seperate LTS in the sources for Dim1. Refer this post for reference -- Logical Table source source query
In BMM you need a join between Dim1 and Fact. Basically your Dim1 is sourced from three different tables which are your dimensions. This would transform your snowflake into star. In your presentation layer you will have all the columns from your dimensions (except for the duplicates, lets say you have column A in both dim1 and dim2, you should map this column in column mapping tab so as to enable BI server to pick the most economical source) and facts.
Hope this clears your question.

How to join 2 star schemas using a Dimensional table( like Bridge Table)

How to join 2 star schemas using a Dimensional table( like Bridge Table) in OBIEE?

Complex joins and Content levels is all you need, have you tried the forum search?

What happens when i remove Dimension table in extended star schema

*how to integrate the flex builder web dynpro and xcelsius?
i found some scenarios like when the content of the table change the chart will changes for the changed data in the table using flash islands and web dynpro.
my scenario is like this.
when i changed the chart with sliders automatically the content in the table will update to the chart level ? but both table and chart will be in the same dashboard. how can i work out this scenario using flash islands, flex and web dynpro>
thanks in Advance*

Hi Sateesh,
Please go through this URL you will get overall Idea about Extended Star schema with DIM ID's,SID's and Data flow.
http://help.sap.com/saphelp_nw70/helpdata/EN/8d/2b4e3cb7f4d83ee10000000a114084/frameset.htm
http://help.sap.com/saphelp_nw70/helpdata/EN/8d/2b4e3cb7f4d83ee10000000a114084/frameset.htm
http://help.sap.com/saphelp_nw70/helpdata/EN/8d/2b4e3cb7f4d83ee10000000a114084/frameset.htm
I hope it will help you.
Regards
Suresh B.G.

Extended Analytics for star schema creation from HFM application

Hi,
I'm trying to create star schema via extended analytics from HFM application but facing below error
3/21/2013 12:30:07 PM : Status : Extracting Metadata
Schema did not previously exist.
Metadata update has failed. : (-2147217900) (One or more errors occurred during processing of command.)
Processing status change: (-2147217900)
Data processing failed. : (-2147217900) (One or more errors occurred during processing of command.)
3/21/2013 12:30:10 PM : Status : Processing completed with errors
Extended Analytics export completed with errors for Application GCS using Label GCS CON.
What could be the possible reason for it?
Also can someone please provide any suitable references or links to learn this EA for star schema creation.
Thanks,
Ravi Agrawal

The error you pasted here is incomplete. Look in the system messages and you will find more complete information that will lead you to the error's cause. Very often this is an error in the database, though sometimes it is caused by a metadata member with an invalid character. To determine whether it is data or metadata that causes the error, you could generate a schema with metadata only and see if the error appears.
-- Chris

Extended Star Schema doubt

Hi ALL,
Fact table --- Dimension table -
Sid Table -- master data values.
Fact table:
Contains Key Figures and Dimensional id's
Dimension table:
Contains Dim Id & SID
SID table:
SID and Master object ID ( eg: Customer ID)
Master Data Table:
contains Customer Attributes , Texts , Hierarchies for that Customer ID.
THis is the Extended Star Schema design.
MY DOUBT:
1)In Dimension table itself if we place that Customer ID(No SID table next) what will happen?
Fact table --> Dimension table --> Master data Table
2)Instead of that SID table we can directly place that CustomerID in Dimension table , so we can reduce one layer inbetween Dimendion table and Master data table.Is it correct or not?
Any one can clarify my doubt.
Regards,
Arun.M.D

SID means 'surrogate ID'. That is an system created id as you know. Main purpose is fastening the search.
Mostly, there exists a rule for Customer or Material ID's.
Like it should be CHAR 10 or CHAR 16.
This kind of alpha-numeric fields are harder to search when compared to integers. Moreover, your customer id can be 10 digits but, this does not mean you will have 1000000000 customers. This is the main reason that, an internal ID is produced. If you have 10000 customers, your SID will be at most 10000.
However, if your customer ID's are starting from 1 and growing up like integers, then your argument would be true. ( but still no way to skip SID creation and direct usage of characteristic ID in fact table)
Also, as mentioned by other friends, there exist the Line Item dimension property if you have only one characteristic in one dimension. That simply does skip the DIM ID creation step, and puts your SID into the Fact table. ( Since you have only one char in the dimension, no combination is possible)
Hope this helps.
Derya

Star Schema tables Creation

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