Our Training Programs

All contents are copyright of their authors.

insert null value

insert null value

albert albert

12yAsked Apr 23, 2014, 5:35 AM1.2kVisual Basic .NET

Hi everybody,

I have this:

[code]

Dim IJavaValue As String = "" '= System.DBNull.Value.ToString()

If String.IsNullOrEmpty(IJavaValue.ToString().Trim) = True Then

IJavaValue = DBNull.Value

End If

[/code]

Then I get the message: Error 43 Value of type 'System.DBNull' cannot be converted to 'String'

And if I try this: IJavaValue = DBNull.Value.ToString()

But then If I look in the Databse I see an empty column and not the value 'NULL' in the column

Thank you

Know the answer? Post it — somebody with the same question will find it here.

It is the same account you read, post and publish with — and you will come straight back to this page.

Vulpes12y ago
Accepted answer
If you're inserting a new record in the database and you want one of the columns to be null, then simply omit that column from your Insert statement.

If it's a nullable column, it will then be set automatically to null.
Vulpes12y ago
If you're updating an existing record, as opposed to inserting a new one, and you have a column where you want to replace a specific value with null, then AFAIK this can only be done using a parameter.

As the Value property is of Object type you can set it to DBNull.Value without falling foul of any type conversion rules.

If it's a string column, then using DBNull.Value.ToString() won't work as this just produces an empty string.
Jignesh Trivedi12y ago
hi,

Agree with Vulpes.

Are you tried below code?
IJavaValue = null; (this is C# syntax)