-
How do you connect two fact tables ? Is it possible ?
sixto.dsilva
- Sep 20th, 2008
As comment by lot of DWH gurus above, two fact tables can be connected only using conformed dimension, defination of conformed dimension:if one primary key of dimension is defined in two fact tables it is called conformed dimension.
-
How data in datawarehouse stored after data has been extracted and transformed from hetrogeneous sources and where does the data go from datawarehouse.
sharuvijay
- Jan 29th, 2009
Data is stored in DW in a relational, aggregatted (if needed), denormalized fashion where the data can be easily analysed.
sixto.dsilva
- Sep 11th, 2008
Data will stored in fact's and dimensional tables, the relational database can be Oracle, Informatic or netezza, it purely depends upon the company which technology they want to go for.
-
-
-
-
-
-
What are the steps to build the data warehouse?
Read Best Answer
Editorial / Best Answer
ankeshjain- Member Since Aug-2008 | Aug 17th, 2008
1. Requirement gathering for BI reports
2. Identify the source databases
3. Designing source to target mappings
4. Designing DWH
5. Designing ETL jobs
6. Development of ETL jobs
7. Data load into DWH
Ravi Teja N
- Sep 16th, 2011
The steps used to develop a DWH are 1. Gathers Operational Source System 2. Data Staging Area 3. Data presentation Area 4. Data Access Tool Lets have a detailed information about each stage: Operat...
mohanbabu
- Aug 20th, 2011
We can create the dwh in two ways i.e
1. top down approach
2.bottom up approach -
What is Fact table
Answer posted by Chintan on 2005-05-22 18:46:03: A table in a data warehouse whose entries describe data in a fact table. Dimension tables contain the data from which dimensions are created.
munavar.shaik
- Jan 20th, 2011
A fact table is an entity representing the numerical measurements or metrics or facts of the business Eg: Billings table,Bookings table,Accounts tableA dimension table is the entity describing th...
ashwinijawalgekar
- Jun 9th, 2010
Fact table is a normalized table divided in to 2 parts Link to all dimension tables -> First part of fact table contains set of foreign keys which links to the respective dimension t...
-
-
-
What is the role of surrogate keys in data warehouse and how will u generate them?
Anindya1281
- Jun 5th, 2011
surrogate key is a substituted key for the business key in data warehouseThis is generated while the loading process (ETL)attributes of surrogate key1) It has the same granularity of the Business Key ...
bcsandip
- Oct 8th, 2010
Along with Jeff's answer, the surragate key also distinguish 2 records with the same combined primary key in the denormalized DWH tables where history is maintained.
-
-
-
What is Dimensional Modelling
rajnsuccess
- Jan 10th, 2011
Dimensional Modelling is a design concept used by many data warehouse desginers to build thier datawarehouse. In this design model all the data is stored in two types of tables - Facts table and Dimen...
kevin0209
- Aug 30th, 2010
Dimension modelling is a logical design technique that seeks to present the data in a standard framework that allows users for high performance accesss.
-
What are Data Marts
Data Mart is a segment of a data warehouse that can provide data for reporting and analysis on a section, unit, department or operation in the company, e.g. sales, payroll, production. Data marts are sometimes complete individual data warehouses which are usually smaller than the corporate data warehouse.
ashwinijawalgekar
- Jun 9th, 2010
Data Marts: Data Mart is a subset of Data Warehousing. Depending upon the management decision the warehouse devides into smaller part according to their respective subject. eg sales is a data mart of xyz warehouse
spatnam
- Dec 9th, 2008
Datamart is a subset of datwarehouse. Data mart deals with single line of business like Sales, Purchase etc. Size of data will be less when compared to Datawarehouse.Some of the different types of datamart are Depndant datamart , Independant datamart, Hybrid datamart
-
What is a Star Schema
Answer posted by Chintan on 2005-05-22 18:34:55: A relational database schema organized around a central table (fact table) joined to a few smaller tables (dimension tables) using foreign key references. The fact table contains raw numeric items that represent relevant business facts (price, discount values, number of units sold, dollar value, etc.)
-
What is a Data Warehousing?
Data Warehouse is a repository of integrated information, available for queries and analysis. Data and information are extracted from heterogeneous sources as they are generated....This makes it much easier and more efficient to run queries over data that originally came from different sources. Typical relational databases are designed for on-line transactional processing (OLTP) and do not meet the...
-
What is the Difference between OLTP and OLAP
Answered by swetha on 2005-03-30 12:00:33: OLTP Current data Short database transactions Online update/insert/delete Normalization is promoted High volume transactions Transaction recovery is necessary OLAP Current and historical data Long database transactions Batch update/insert/delete Denormalization is promoted Low...
-
What is surrogate key ? Where we use it explain with examples?
Read Best Answer
Editorial / Best Answer
Answered by: saravanan
- Dec 2nd, 2005
Surrogate key is a unique identification key, it is like an artificial or alternative key to production key, bz the production key may be alphanumeric or composite key but the surrogate key is always single numeric key. Assume the production key is an alphanumeric field if you create an index for this fields it will occupy more space, so it is not advisable to join/index, bz generally all the datawarehousing fact table are having historical data. These factable are linked with so many dimension table. if it's a numerical fields the performance is high
P.Manideep
- Oct 29th, 2017
Surrogate key is system generated key. It is a column or set of columns declared as primary key instead of real of natural key.
Anukul Thawarey
- Aug 8th, 2017
Just to add on to this point, we can also have date stamp as in the format (yyyymmdd) which is actually an 4 Byte unsigned integer to keep track of the historical data. This date stamp column can also be considered as an surrogate key.
Data Warehousing Basics
Read Best Answer
Ans