How to delete duplicate rows from tables with no primary key!

Ans) Use SET ROWCOUNT value

Ex:-     SET ROWCOUNT 2
           DELETE FROM table_name WHERE somecolumn1=somecolumnvalue
           SET ROWCOUNT 0

         Imagine a table having 3 similar rows.The above delete statement executes 2 times deleting the extra 2 rows.Dont forget to set ROWCOUNT to 0 after succesfull query execution.

INDEX Statement

• Indexes are used to search/query the data from the table, without reading the entire table.

Advantages:-

1. Allows the application to find the data fast from database thereby increasing the query speed.

DROP,DELETE & TRUNCATE

DROP:- Tables,Databases,Indexes can be easily removed using DROP Statement.
           
EX:-DROP TABLE table-name
                 Deletes table completely from database.

 similarly DROP INDEX index-name
              DROP DATABASE database-name

What is the advantage of SET NOCOUNT ON ?

• Use Nocount at the begining of all your Stored procedures,Functions and Triggers

In case of regular T-sql statements(Insert,Update,Delete,Select) execution, we observe a message like some 20(rows) affected in the result window.This is actually a message database return internally to the client.This costs our application in terms of performance because information is sent back to us(client).

This intensifies when we have many operations(Insert,Update,Delete) in a stored procedure.That means each operation returns internal message within the stored procedure execution cycle.

Difference between ADO & ADO.Net ?

Difference between Data Reader & Data Set ?

Data Set ?

Data Adapter

Data Reader

LIKE Statement ?

Explain Drop Query ?

TRIGGERS ?

What is a View ?

Primary Key Vs Unique Key ?

Primary Key Vs Foreign Key ?