SQL Truncate vs. Delete

By now as you know, in this post I am going to discuss about two SQL commands we use regularly to clear data in our tables.

Usage

1. DELETE FROM TABLENAME
3. TRUNCATE TABLE TABLENAME

Even though they do a similar thing, there are some differences which makes them unique commands.

	DELETE	TRUNCATE
1.	Considered as Data Mining Language (DML) statement.	Considered as Data Definition Language (DDL) statement.
2.	Can be used to delete all or part of data in a table.	Will delete all the data in a table.
3.	Will log the actions.	There will be no logging on record deletion.
4.	Will use more locks.	Will use fewer locks.
5.	Will use more resources.	Will use less resources.
6.	Slow.	Fast.
7.	Will not reset the identity seed.	Will reset the identity seed to 0.
8.	Can be used to delete data in tables having relationships.	Cannot use in tables having relationships.
9.	Can be used in tables involved in log shipping or replication.	Cannot be used in tables involved in log shipping or replication.
10.	Transaction can be rolled back.	No rollback.
11.	Table may keep the empty pages. Can be released by running, SHRINKDATABASE (Database Name).	Data pages related to the table will be de allocated and returned to the system.
12.	Related Triggers are fired.	Triggers are not fired.

 

If you used DELETE to fully remove all the records, you can reset the identity value by running the following command.

1. DBCC CHECKIDENT (TABLENAME, RESEED, 0)

If you do have some rows left in table, simply replace 0 with the last identity column value. For example if you put 5 instead of 0 then the next record inserted into the table will have an identity column value of 6.

If you jus need to check the current identity value just use the following command.

1. DBCC CHECKIDENT (TABLENAME, NORESEED)

Beerenberg Strawberry Farm – Hahndorf South Australia

If you like Strawberries and would like to pick your own, then there is a good place you can do it in Hahndorf South Australia.

It is called Beerenberg Strawberry farm, located on the Mount Barker road. If you are planning to visit them to pick your own strawberries you need to visit them from October to May which is the Strawberry season. Else you can buy their produce from the shop.

Normally they are open everyday except Christmas day from 9:00AM to 04:00PM. Anyway it is always good idea to give them a call before going.

There is enough parking on site and there will be a helper on busy days.

Once you are there you can visit the shop to get permission to enter the patch. When I was there entry was $ 3 per person. They will also provide containers to bring the Strawberries you pick. Remember to pick whatever amount of Strawberries you would like to buy. Normally you can keep them from few days to about 10 days in fridge (obviously you can keep bit more days than this but then they wont be tasting fresh). Once you have enough Strawberries picked you can bring them back to the shop where they will weigh it, so you can pay. While I was there they sold a Kilo of Strawberry for $ 9, but the price always changes from season to season, so it is always best to check the price they are selling before heading to the Strawberry patch.

If you are travelling with young children, I do not recommend a pram since the ride will be bumpy, best is to use a child carrier sling.

Address: Beerenberg Strawberry Farm,
Mount Barker Road Hahndorf,
South Australia, 5245
Phone: +61 8 8388 7272
Fax: +61 8 8388 1108
Email: admin@beerenberg.com.au
Web: http://www.beerenberg.com.au/

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Importing Data into SQL

If you need to import data from a file, this can be achieved by using SQL Bulk Insert command. Recently I did use this method to import some 500 000 data from few comma separated value (CSV) files and thought to share it with you. What you need to remember is, if you are importing data from more than one file the data should have the same format through out the files.

This is a sample set of data I imported into my table from the file named File1.csv.

Login,Name,Date,Result,Pass

U0001,Roman Silva,1/10/2010 17:23,100,TRUE

U0002,Anthony Don,28/09/2010 10:01,70,TRUE

U0003,Saman Perera,16/09/2010 11:31,90,TRUE

U0004,Silvia Raz,26/09/2010 22:11,40,FALSE

U0005,Rebecca Maine,18/09/2010 11:30,100,TRUE

I used the following script to create a temporary table for my imported data.

1. SET ANSI_NULLS ON
2. GO
3.  
4. SET QUOTED_IDENTIFIER ON
5. GO
6.  
7. CREATE TABLE [dbo].[TABLENAME_ImportedData](
8.     [LoginId] [NVARCHAR](50) NOT NULL,
9.     [Name] [NVARCHAR](200) NULL,
10.     [Date] [DATETIME] NULL,
11.     [Result] [INT] NULL,
12.     [Pass] [NVARCHAR](8) NULL
13. ) ON [PRIMARY]
14.  
15. GO

To fetch data from the file I used the following script.

1. BULK INSERT [TABLENAME_ImportedData]
2. FROM 'D:\DataFiles\File1.csv'
3. WITH (
4.          FIELDTERMINATOR =',', -- Since my columns are seperated using commas (,).
5.          ROWTERMINATOR ='\n',  -- Since each data row is in its own line.
6.          FIRSTROW = 2          -- Since my first row is having column names. Please note FIRSTROW is not recommended to skip the column names.
7.       )

While running the script I faced an issue with the date since my server was set to US English as the default language. In US English the dates should be in MDY format. So I had 3 choices, either to change the date formats on my data files, change the server default language to another language which has its date format as DMY or change the date format of the server. I used the easy way to change the date format of the server by running  the following command.

1. SET DATEFORMAT dmy

If you like to change SQL server default language and need help please read my article on that.

Changing SQL Server Default Language

If you needed to change the default language of a SQL Server login you can do so by using sp_defaultlanguage command.

First determine the current default language by using the @@language variable as follows.

1. SELECT @@language

Then choose the language you want to change to from the available languages. You can find the available languages by the following command.

1. EXEC sys.sp_helplanguage

After selecting the language wanted to change, run the following command to change the default language, I am changing it to British using the following command.

1. DECLARE @Login NVARCHAR(30)
2. SET @Login = SYSTEM_USER
3. EXEC sp_defaultlanguage @Login, 'British'

Run the @@language to see whether the default language is changed as you wanted. Do not forget to use a new query window to see the changes.

Change Quick Access Default Application Icons on Samsung Galaxy S2

If you ever wanted to change the quick access default application icons on Samsung Galaxy S2 you can do this by going to applications screen. For example as seen in the following image we have Phone, Contacts, Messaging and Applications as the default set of icons.

To change this first go to the applications page by touching Applications.

Then touch the menu button on the phone to activate the menu and select Edit. This will take you to edit screen view. Now it is simple as dragging the application icon you want on your quick access to the icon you need to be replaced.

When you are satisfied, touch on the back button to save the changes. If you need to ignore the changes press the middle button.

As seen in the following images I have replaced the Contacts with Play Movies. Also if you want you keep only 3 or less icons in quick access you can achieve this by deleting unwanted icons using the edit view.

Beetaloo Reservoir – Beetaloo South Australia

If you like to enjoy nature like me another place you can visit in South Australia is the Beetaloo Reservoir in Beetaloo which is managed by SA Water. It is about 220 kms from Adelaide. It is a reservoir built in the year of 1885 with a capacity of 3150 mega liters of water and having a catchment area of 4856 hectares. Its wall is 33.53 meters high and the maximum water level could reach 23.88 meters.

After parking your car you need to walk for about 10 minutes to visit the lookout area. Walk is not difficult, but if it rains some areas might be slippery. You do not need a 4WD to reach Beetaloo Reservoir. Its gate is open from 9:00 AM to 4:00 PM each weekday and on Saturday, Sunday and public holidays open till 5:00 PM.

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Handler was not added through the Sys.UI.DomEvent.addHandler method.

Sometime back I started getting this error in all the forms in which AJAX tools were used. The thing worried me most is that there were no changes made to the project source code. Later a friend of mine found that it is happening because of the wrong AjaxControlToolkit.

As I feel this dll swap happens when a control is dragged from the Visual Studio toolbox because the toolbox is referenced to a newer version of the toolkit than the project was using.

If you are also getting this error simply delete all the AJAX related files and folders in your projects’ bin directory. Once you are done there should not be any folders such as ar, cs, de, etc. Also remove the AjaxControlToolkit.dll. Then copy the version of the toolkit dll your project was using earlier to the Bin directory. Now clean and build your project to see the error disappear.

If you are still getting the error after correctly doing all this you might be getting the error due to another reason causing the same error. Since there are many reasons for this same error you better check the internet for other reasons to find out the exact reason causing the error for you.