Tag Archives: SQLServerPediaSyndication

SQL Triggers – An Introduction

Posted on December 8, 2018 by vivekjohari

SQL Triggers – An Introduction Contents Introduction Magic Tables Difference between Stored Procedure and Trigger DML Triggers After Triggers Syntax of the After trigger Example of After Trigger for Insert Example of After Trigger for Delete Example of After Trigger … Continue reading →

Posted in Most Imp SQL Concepts, SQL Advanced, SQL Server, SQL Triggers | Tagged , , , , | 33 Comments

Isolation levels in SQL Server

Posted on August 19, 2012 by vivekjohari

Isolation levels :- Isolation level is required to isolate a resource and protect it from other transactions. This is achieved with the help of locks but what locks are needed and how they can be established is decided on the … Continue reading →

Posted in SQL Isolation Level, SQL Server | Tagged , , | 33 Comments

SQL Server Functions- An Introduction

Posted on August 2, 2011 by vivekjohari

SQL FUNCTION: – Function in a database can be defined as the code segment consisting of a logical group of SQL statements which takes some input arguments (if required), run in a sequential order and returns the output either in … Continue reading →

Posted in Most Imp SQL Concepts, SQL Functions, SQL Server | Tagged , , | 31 Comments

Sql Joins- Inner Joins, Self Joins, Outer Joins, Cross Joins

Posted on January 2, 2010 by vivekjohari

I generally feel that people are afraid of Joins in SQL Server. But if they know what the different types of Joins in SQL Server are and how they can be best used then they really enjoy using them. By … Continue reading →

Posted in Most Imp SQL Concepts, SQL Joins, SQL Server | Tagged , , | 33 Comments

Difference between Subquery, Nested Subquery and Correlated Subquery

Posted on September 29, 2009 by vivekjohari

Difference between Subquery, Nested Subquery and Correlated Subquery Query Query can be defined as a way to inquire the data from the database. It is used to extract the data from one table or multiple tables depending upon the user … Continue reading →

Posted in Interview Questions, Most Imp SQL Concepts, SQL Queries Sub-queries, SQL Server | Tagged , , | 102 Comments

Sql server Constraints – Primary Key, Foreign Key, Unique Key, Not Null, Check Constraints

Posted on August 19, 2009 by vivekjohari

Introduction A constraint is a property that is assigned to a column or a group of columns to prevent incorrect or corrupt data from entering into the tables. These constraints ensure the accuracy and reliability of the data into the … Continue reading →

Posted in Most Imp SQL Concepts, SQL Primary Key Constraint, SQL Server | Tagged , , , | 31 Comments