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Showing posts from August, 2012

Disadvantages of Normalization

Dear Friends, We allready know Normalization is the process to optimize the storage and increase the performance of system by eliminating redundancy from database. But there is also circumstances when Normalization can reduce database performance.Due to Joins-Jonis-Joins system makes complex to select a simple record-set. A normalized database requires much more CPU , memory ,  and I/O to process transactions and database queries than does a normalization database. Ref:  1.)  advantages-disadvantages-normalizing-database 2.)

Serial number or row number

Sometimes there would be a requirement to add serial number (or) row number to the result set. Example: The requirement would be to select some columns from the database tables along with Serial Number like below SNo Customer_Name Customer_Phone_Number 1 aaa xxx-xxx-xxxx 2 bbb xxx-xxx-xxxx So, in this post we will see how we can select that using T-SQL on Microsoft SQL Server 2008 We can achieve this in several ways: 1) Using  Row_Number ()   Row_Number() Returns the sequential number of a row within a partition of a result set, starting at 1 for the first row in each partition.  T-SQL Script:          SELECT ROW_NUMBER() OVER (ORDER BY CUSTOMER_ID) AS [S.No]                         ,CUSTOMER_NAME                         ,CUSTOMER_PHONE_NUMBER         FROM database.dbo.tblTableName 2) Using  Identity (Property)   Identity() property creates an identity column in the table. So, first we need to cre