What is Extension table?
My understand is “base table has default colums. But Extension table is the table in which we can add additional columns other than its base tables columns Is... Read more »
Archive for September, 2008
When will we use local and server database?
loca db is used while developing the application.check-out the required projects from the server database,do changes as required and check-in the modified projects... Read more »
Cascade Delete Property for Link ?
This property is to clear the relation or unmapped child date to be removed from the DB. Cascade Delete has 3 types of values. 1) None 2) Clear 3) Delete 1) None:... Read more »
What are Data Marts ?
Data Mart: a data mart is a small data warehouse. In general, a data warehouse is divided into small units according the busness requirements. for example, if we... Read more »
What are slowly changing dimensions ?
Dimensions that change over time are called Slowly Changing Dimensions. For instance, a product price changes over time; People change their names for some reason;... Read more »
What are modeling tools available in the Market ?
These tools are used for Data/dimension modeling 1. Oracle Designer 2. ERWin (Entity Relationship for windows) 3. Informatica (Cubes/Dimensions) ... Read more »
What Snow Flake Schema ?
Snowflake schemas normalize dimensions to eliminate redundancy. That is, the dimension data has been grouped into multiple tables instead of one large table. For... Read more »
Why are OLTP database designs not generally a good idea for a Data Warehouse ?
OLTP cannot store historical information about the organization. It is used for storing the details of daily transactions while a datawarehouse is a huge storage... Read more »
What is the Difference between OLTP and OLAP ?
OLTP Current data Short database transactions Online update/insert/delete Normalization is promoted High volume transactions Transaction recovery is necessary OLAP Current... Read more »
What are the various Reporting tools in the Market ?
INEA MS-Excel Business Objects (Crystal Reports) Cognos (Impromptu, Power Play) Microstrategy MS reporting services Informatica Power Analyzer Actuate Hyperion (BRIO) Oracle... Read more »
What are non-additive facts ?
fact table typically has two types of columns: those that contain numeric facts (often called measurements), and those that are foreign keys to dimension tables.... Read more »
What is Normalization, First Normal Form, Second Normal Form , Third Normal Form ?
Normalization : The process of decomposing tables to eliminate data redundancy is called Normalization. 1N.F:- The table should caontain scalar or atomic values. 2... Read more »
What is a CUBE in datawarehousing concept?
yes,cube is a logical representation of data.12 steps are required for the creation of cubes.its mainly used for analysis purpose. we can analyse which product can... Read more »
How do you load the time dimension ?
Every Datawarehouse maintains a time dimension. It would be at the most granular level at which the business runs at (ex: week day, day of the month and so on).... Read more »
What is degenerate dimension table?
Degenerate Dimensions : If a table contains the values, which r neither dimesion nor measures is called degenerate dimensions.Ex : invoice id,empno Read more »