9/15/12

Data Warehousing SCHEMAS

A schema is a collection of database objects, including table, views, indexes and synonyms.

 There are some special architectures which arranges the schema objects in the schemas models. The most common of them are :

 * Star Schema
* Snowflake Schema
* Fact constellation Schema


9/4/12

What is a Data Warehouse?

A very exciting and one of the hottest topic currently in the IT world is DATA WAREHOUSE. The tools which are used for the same are among some of the hot skills example INFORMATICA, TERADATA etc.



8/19/12

Iterative Statements in PL/SQL

In the last post on PL/SQL, we had seen Conditional Statements and how they can be used. Today we will be learning about Iterative Statements in PL/SQL.


As we all know the types of Iterative statements that are there in a programming language. PL/SQL also has the same iterative statements and the functioning is also the same, but the only thing different is their syntax. 


So lets not waste any time and move on to the topic.



UNIX and SHELL Scripting : General Purpose Commands

As everyone is aware of UNIX nowadays thanks to UBUNTU, which has made this platform very popular.

In this post we won't be learning about UNIX or its architecture but what we will be learning are the General Purpose Commands required for UNIX and SHELL Scripting.

UNIX has a lot of commands which perform different functions, and also it has different types of SHELLS like BASH, KORN SHELL. All the shells in unix has some or the other limitation on commands.

So we are considering our shell as BASH, as we all work in BASH shell normally.


7/25/12

Conditional Statements in PL/SQL

Conditional Statements in PL/SQL are same as conditional statements available in java, c++, c or any other language. PL/SQL allows processing of data using the following conditional statements:

    * IF
    * CASE


7/6/12

GROUP BY vs DISTINCT in SQL

This question has to come my mind many times and also I have been asked the same question many time. That what should be used GROUP BY or DISTINCT, as both perform the same thing.


So, after researching and using both statements and checking the performance using some scripts from here and there, I have come to the conclusion that GROUP BY performs much better then DISTINCT.

Now before, we move on to more discussion, lets first understand what does actually both do.