Question

I am developing a C# application in my company.
The application uses a SQL Server database via ADO .Net.
The application uses the ADO .Net data provider for SQL Server shipped with the .Net framework 4.

We are facing a problem when inserting a string programmatically into a varchar field.

Example

Let’s consider the database table named MY_TABLE with the following columns :

• MY_FIRST_COL int
• MY_SECOND_COL varchar(250)

I insert a record (REC1) into MY_TABLE by executing the following SQL query within SS Management Studio :

insert into MY_TABLE (1, "");

Then I select REC1 by using SSMS.
Then I copy the string contained in MY_SECOND_COL field.
Then I paste the string into Notepad++.
I notice the string is made up of 0 characters.
OK it makes sense !

Now I insert programmatically a record (REC2) into MY_TABLE by using an SqlCommand object.

Here is the string contained in the CommandText property :

insert into MY_TABLE (@p0, @p1);

Here are some values contained in properties of the SqlParameter object corresponding to the second parameter :

• DbType : System.Data.DbType.AnsiStringFixedLength
• Direction : Input
• IsNullable : false
• ParameterName : “@p1”
• Precision : 0
• Scale : 0
• Size : 0
• SqlDbType : Char
• Value : “”

Then I select REC2 by using SSMS.
Then I copy the string contained in MY_SECOND_COL field.
Then I paste the string into Notepad++.
I notice the string is made up of 250 characters.
Why ?

Any help will be greatly appreciated

Answer 1

SqlDbType : Char

That’s your problem. You want VarChar. Chars are fixed width strings, padded with spaces.

SqlDbType:

Char String . A fixed-length stream of non-Unicode characters ranging between 1 and 8,000 characters.

VarChar String . A variable-length stream of non-Unicode characters ranging between 1 and 8,000 characters. Use VarChar when the database column is varchar(max).