How can I prevent a user from saving a record with a null value?

I'm very new to database programming and I've 开发者_如何学JAVAgot a small database (SQL CE 3.5). It has a "LastName" column that doesn't accept nulls. I'm using the BindingNavigator to get around. Do I have to set an event similar to below for every control on that navigator. Or is there an easier way around it?

I'm using C# with .NET 3.5 and WinForms. This is also just a single table db.

        if (!string.IsNullOrEmpty(lastNameTextBox.Text))

        {
            this.Validate();
            this.tblMembersBindingSource.EndEdit();
            this.tableAdapterManager.UpdateAll(this.dataSet1);
        }
        else
        {
            MessageBox.Show("The Last Name Field cannot be empty");
        }

Thanks

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You should really be using:

if (!string.IsNullOrEmpty(lastNameTextBox.Text))
{
  ...
}

Also, why not just use the RequiredFieldValidator to ensure that the form can't be posted back without a value in that field?

http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.requiredfieldvalidator.aspx

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There are a couple ways you could do it.

The first would be in your SQL code. You could use isnull(lastname, 'something') - http://msdn.microsoft.com/en-us/library/ms184325.aspx

Or you could give the column a default value in the database -

ALTER TABLE your_table_name ADD CONSTRAINT
Name_of_Constraint DEFAULT 'value' FOR column_name

That work for you?