Author: Shikha Katariya

Logical Operators

Logical Operators

In this post , we will discuss about Logical Operators. AND Operator : AND Operator is used to filter the records based on two or more than two conditions. It is specified in the WHERE...

Deadlocks in SQL

Deadlocks in SQL

For a transactional database , Deadlocks in SQL may be defined as a situation in which two or more oracle sessions are competing against the same data and waiting for each other to release...

TCL commands

Transaction Control Language (TCL Commands)

COMMIT : This command is used to save the users action  until that particular point of time. Until and less commit is performed , the changes made by transaction are not made permanent. Syntax...

DML commands

Data Manipulation Language ( DML Commands)

Data Manipulation Commands are used for managing the data within the database objects. These commands are not auto commit unlike DDL commands.   Types of Data Manipulation Language ( DML Commands) : 1. SELECT...

Anonymous PLSQL block

Anonymous PL/SQL Block

Definition : The PL/SQL block that has no name is called Anonymous PL/SQL Block. Structure : Since the Anonymous Blocks have no names , therefore the header section is completely missing. They only consist...

Null Functions

Null Functions

Null Functions : Null Functions are used to handle Null values . Following different kinds of Null Functions are available in Oracle. 1. NVL Function : NVL stands for Null Value. This Function is...

ETL testing Guide

ETL Testing Guide

Data Warehouse Concepts. Introduction – ETL Testing. ETL Development Life Cycle. ETL Testing Life Cycle. Test Strategies for ETL Testing.

Surrogate key in Data Warehouse

Surrogate key In Data warehouse.

Defining Surrogate Key : Surrogate Key may be defined as a system generated key which is used to maintain unique records in the Data warehouse databases. Need for Surrogate key : We all know...

Slow changing dimension in informatica

Slow Changing Dimensions in Informatica (SCD)

Defining Slow Changing Dimensions: Change in the city names for e.g. Madras to Chennai , Change in the price of the product , Changes in the residential location of the people , Changes in...

DUAl table in oracle

DUAL Table in Oracle

Defining Dual Table : DUAL is a Special table having one row and one column. The Datatype of the Column is Varchar2(1) , Column Name is ‘DUMMY’ and Value is ‘X’. It is created...