T-SQL

Think while Rename a Column Name of Table in SQL.

If someone tries to rename the column of table then we write a query as

SP_RENAME  'TableName.[OldColumnName]' , '[NewColumnName]', 'COLUMN'
--we use as
SP_RENAME  'DimCustomer.[FirstName]' , 'CustomerName' , 'COLUMN'
--Mistakenly,
SP_RENAME  'DimCustomer.[FirstName]' , '[CustomerName]' , 'COLUMN'
which gives the column the name [CustomerName], not CustomerName.
For rename the column 
http://blog.sqlauthority.com/2008/08/26/sql-server-how-to-rename-a-column-name-or-table-name/

You don’t use the [] escape in the second argument but by mistakenly if we use ‘[CustomerName]’ as new column name instead of CustomerName.

It sucessfully updates the column but while we select that column it’s now gives the error as

"Either the parameter @objname is ambiguous or the claimed @objtype (COLUMN) is wrong"

Also while we try to drop the column itself we cannot delete it. It also gives error as

ALTER TABLE DROP COLUMN failed because column '[CustomerName]' does not exist in table 'Customer'.

Does that mean we have to recreate the customer table since the renamed column [CustomerName] cannot use in select statement too.

Well there is a method for changing the mistakenly rename column ‘[CustomerName]’ to CustomerName . Just simple you need to go to the table DimCustomer and then click plus sign of the table and then you can see the list of columns of DimCustomer table then right click and add New Column tab which will edit all the list of columns and there you go just change the ‘[CustomerName]’ to CustomerName . This will solve the issue we are having.

columnrename

If someone by mistakenly rename the column as above and getting similar issue this post will be surely helpful.

Also, there might be any alternative T-SQL method then please suggest some idea that will surely helpful.

Thanks,

Anil Maharjan

How can we rollback mistakenly UPDATE statement change in SQL Database.?

Hello all,

Beside than my regular helpful blog posts, it’s just a discussion type blog post that might be useful to all of us.

Let’s say we have a table customer and If someone tries to update a single row within it but by mistakenly update the entire row within a customer table. while update query someone forgot to put where condition and now all the rows of customer table are updated.

Is there any solution to rollback the update statement and retrieve all rows back for that customer table.?

After research ,I have found as the only option is to restore that previously backup Database . If our database runs in full recovery mode, we can:

* backup the transaction log

* restore the database from a full backup

* restore all transaction logs (in sequence) to the time right before the accident occurred.

Also, there is some cool tool called ApexSQL-Log which allows us to rollback the changes. But I haven’t tried it yet before but I have downloaded the product and going for a test. You can easily download from the link below: http://www.apexsql.com/sql_tools_log.aspx

So if anyone knows some idea regarding on this and if there is any solution lately with the release of MS-SQL 2012  then really want to here.

Regards,

Anil Maharjan

How to drop/delete all the user define tables within a SQL database.

Hello all,

Firstly on this lovely Valentine’s day esp, I wish Happy Valentine’s day to all the loved ones 🙂 .

I would like to post some another blog which might be helpful to the one who works in SQL.

Sometimes we might need to delete all the user define tables from a Database in SQL. So, If any one just need to delete all the user define tables from a SQL DB then you can use just a simple Query as below:

USE Database:--replace with your Database name.
GO
DECLARE @tbl_name as varchar(256)
DECLARE @flag as int
DECLARE @name as varchar(256)
set @flag=(SELECT count(*) FROM sysobjects where type='U')
while(@flag>0)
BEGIN
set @name=(SELECT top 1 name FROM  sysobjects where type='U')
set @tbl_name = 'drop table ' + @name
exec(@tbl_name)
print @tbl_name
set @flag=@flag-1
end

within a database we can have objects as TABLES, VIEWS, FUNCTIONS, PROCEDURES, TRIGGERS, etc. are there. So, If anyone just want to delete only User Define TABLES without dropping the entire Database and other objects the above query is the best one. If someone drops the database that means those objects needs to be recreated. So,in order to save the time and for quick approach I found this useful .

This is just a simple example and looks simple but it might help for the one who indeed needs such a solution.

Regards,

Anil Maharjan

How to delete a particular row from a table in SQL.

Hello all,

After such a long time , I would like to post some another blog which might be helpful to the one who works in SQL.

Sometimes we might need to delete the particular row from a table in SQL Database.

While working someone might mistakenly  insert the duplicate same data multiple times within a table that might contains a huge amount of data and after populating that table .He/she wants to delete that duplicate data inserted from a table.

So, for this we might drop and recreate the table or truncate the table and insert again. But, if it is a large table then it would be better to find the duplicate row within a table and delete duplicate one which helps in time consumption and server utilization too.

In order to obtain this , we can simple used a simple query as

WITH newtbl as(SELECT *, 'row number'=ROW_NUMBER() over (order by FirstName) FROM CustomerList)
DELETE FROM newtbl WHERE [row number]=2

--where CustomerList is a user table having dublicate record.

This is the tested script for Test Database where CustomerList table have duplicate records which needs to be delete.

This is just a simple example and looks simple but it might help for the one who indeed needs such a solution.

Regards,

Anil Maharjan

How to move the tables without having clustered index from one file group to another file group simply in SQL 2008.?

Hello All,

This might not be the proper for the blog post but it helps me to understand more regarding the transfer of tables within different file groups in MS-SQ L. So, I think it will be more helpful to the others who indeed needs such information related to file groups .

I had posted as below within MSDN

http://social.msdn.microsoft.com/Forums/en/transactsql/thread/d35ab8ff-a6a1-458c-b3e4-b2c9f6a1ff83

I have few issues regarding the transfer of the tables from one file group to another file group  in SQL 2008 and also How can we  backup and restore the particular database based on file group level.

Let’s say I have a tables stored within the different FG. such as

Tables                                                                                                                           File group

Dimension tables                                                                                                              Primary

Fact tables                                                                                                                           FG1

                                                                                                                                            FG2…

zzz_tables                                                                                                                           DEFAULT_FG

dim.table1                                                                                                                           DEFAULT_FG

dim.table2                                                                                                                           DEFAULT_FG

…                                                                                                                                             ….

Here all I want to transfer the dim.table1 ,dim.table2  from  DEFAULT_FG to the Primary File group .So is there simple methods for transfer the dim.table1,2  from one FG to another .I have tried somewhat but I couldn’t get the exact way .So if someone have better idea please share your knowledge that would be really appreciated.

Secondly after moving those dim.table1 ,dim.table2 from DEFAULT_FG to Primary ,All I want to backup and restore the database only containing  the Primary and FG1,FG2… not a DEFAULT_FG.Is it possible or not.?

Currently I have no any clustered index defined within the dim.table1 ,dim.table2 and so on.

Cannot we transfer the tables from DEFAULT_FG to another FG without having clustered index on that tables or without select/insert operation so that I couldn’t have to recreate the tables. I have researched somewhat and found that we couldn’t  move the tables without having the clustered index to another file group simply in MS-SQL so sad :(..!!!

Hope to hear from the one who knows better approach for this kind of task .Your simple help will be much appreciated.

Some helpful links regarding transfer of tables between different FG’s and restore/backup FG’s.

http://www.sqlservercentral.com/articles/Administration/64275/

http://www.sqlservercentral.com/Forums/Topic695367-146-1.aspx#bm695717

http://sqlserverpedia.com/wiki/Restoring_File/Filegroup_Backups

Well after all my full day research on this topic had paid off, I finally got the solution and am so happy to research on these things. It makes us feel really happy after all our research and hard work doesn’t goes as waste.

Finally I got what I am looking for and want to make sure that I am able to transfer the tables from DEFAULT_FG to another FG without tables having clustered index on that tables .

With the help of the link below I finally got my solution where Roberto’s coded store procedure simply works for this.

Really thanks to him for his great post and thanks to everyone for their response in MSDN and their valuable time.

http://gallery.technet.microsoft.com/scriptcenter/c1da9334-2885-468c-a374-775da60f256f

Regards,

Anil Maharjan