Connecting to a SQL database from ASP .NET | Muhammad Faizan khan (MFKJ) | |||
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This tutorial (divided in two parts) will show you how to connect from an ASP .NET web application to a SQL database using SQL authentication. To accomplish this you need to follow a series of steps, first to change some of the settings of SQL Server 2000 and create a database and a user and then to actually connect to the database using ASP .NET with Visual Studio .NET. I suppose you're going to use the MSDE 2000 (Microsoft SQL Server 2000 Desktop Engine) - the free version of the database. First set up the database using the tutorial named 'Setting up MS SQL Server 2000'. Authentication ModeThere are two possible authentication modes for MSDE: Windows Integrated and SQL Login. By default, MSDE is using Windows Integrated authentication. But if you create some website that you are preparing to upload to a webhost, you'll probably want to prepare it for SQL Login. Because MSDE 2000 (being free) doesn't have a user interface we need to change the authentication mode from the registry. Navigate using regedit to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\MSSQLServer and double-click theLoginMode key. The value that LoginMode currently holds is probably 1 which means Windows Integrated. We change this to the value 2, which means Mixed Mode:  Creating a new databaseOpen Microsoft SQL Web Data Administrator (if you don't have it installed read this) - if you don't start it from the Start Menu you can usually find it at http://localhost/webadmin. First login using the Windows Integrated option, and also leave the other fields with the default values - just press the Loginbutton. After you are logged in, the Databases page shows up. It displays the available databases:  Click on the Create new database link. You are asked to enter a name for the new database - enter 'MyDB' (without the quotes) and click Create. After the database is created you can see that no there are no tables to be displayed. So let's create one by using the Create new table link. When you are prompted to enter a new name for the table choose 'MyLinks' and click Create. The table is created and we are redirected to the Edit Column page where we can add a new column to the table, and we will. In the Column Name field enter 'Title'. Leave the Data Type to char, but change the Length property to '64' (characters). Leave the rest unchanged and press Add. The new column was created but let's create another one. Again click on the Create new column link and set the Column Name to 'URL' and the length field to '128'. Press submit and the second column is created:  From the left side menu choose Query cause we're going to store a value. Run the following query there:
Now that you are still at the Query page, run the following query to see the inserted rows:
Look at the bottom of the page and you'll see the row we just inserted:  Creating a new user Now you're going to create a new user with a password, that we'll use to connect to the database from the web application. Again, we'll accomplish using Microsoft SQL Web Data Administrator.From the left menu choose the Security link This will bring you to the Security page where you'll encounter two icons. ChooseLogins. The Logins page shows the curent accounts that are allowed to use access the database along with their privileges. Above the table, there is a Create new login link. Click it and from the page that shows up choose Sql Login. For the login name I recommend using aspnet and for the password... well, it's your choice. After you complete the fields and click the Create Login link, the Editing login aspnet page shows up. Go to Database Access section and check the checkbox next to MyDB:  Save changes and you can now see the result - the login has been added:  There's one more thing. We need to set the privileges for this user. So on the left menu choose Databases, from the list of the databases that showed up click MyDB, of course. The left menu now has some other new items:  Choose Users and now a page shows up with a table that contains the users that have access to this database. Obviously, we are interested in aspnet, so click the Edit link next to it. The roles for this user show up with a checkbox next to them. As we currently don't want to waste time, check them all, except db_denydatareader and db_denydatawriter. Save the settings with the Save User button.We're done. Now you can test it. Logout (there's a small X button in the upper-right corner of the page that will log you out) and at the login page choose SQL Login instead of Windows Integrated and enter the username (aspnet) and the password you choosed earlier. That's it, the database is set up, now we only have to connect to it from the ASP .NET web application. Now we're going to make the ASP .NET web application that will establish a connection to the database we created. We're going to do it the Visual Studio way - as quick as possible with very few effort. So fire up Visual Studio .NET and create a new ASP .NET Web Application - name it 'SQLConnection'.  Do a Ctrl+Alt+S shortcut that brings the Server Explorer window. Browse through Server > YourComputerName > SQL Servers >YourInstanceName.
We are interested in the MyDB database, and if you click the [+] sign next to it you can see that it is freely browseable. It can be browsed because Visual Studio authenticates using Windows NT Integrated Security but one of the purposes of this tutorial is to connect to it using SQL Authentication (in fact, that's why we created that SQL login in the first tutorial). We can simply connect to MyDB using different authentication: right click the database name and choose Change Login...uncheck the checkbox named 'Use Windows NT Integrated Security' and in the Login field enter the login name that we created in the first tutorial (aspnet) and the password you chose: | ||||
Saturday, August 3, 2013
Connecting to a SQL database from ASP .NET
