allow null in database

Question

I have a query where I calculate the total sum of an item based on different prices.
If I enter a new article and I leave certain cells empty, the price is calculated correctly with an empty cell.
If I now put a value in the empty cell, the calculation also happens correctly, but the cell cannot be emptied afterwards (no empty cell is allowed).
In the DB it says "Allow null's"
This only happens in cells where a number is stated, not in a cell with text.

CREATE VIEW dbo.Particulier
AS
SELECT        Auto_Merk, Plaats, ref_vast, ref_es, Ref, Omschrijving, Datum, snijden, snijden_foto, Bol, ref_set7P, ref_set13P, werk_vast, werk_orig, werk_es, opleg_13P, Caravan, prijs_vast, prijs_es, prijs_set7P, prijs_set13P, Spoiler_ref, 
                         Spoiler_prijs, Codering, Codering_prijs, Uitbreidingsset, Uitbreidingsset_prijs, PDC_uitschakeling, ROUND((prijs_es * 1.21 + werk_es + prijs_set7P + ISNULL(Spoiler_prijs, '0') + ISNULL(Codering_prijs, '0') 
                         + ISNULL(Uitbreidingsset_prijs, '0')) / 10, 0) * 10 AS geplaatstes, ROUND((prijs_vast * 1.21 + werk_orig + prijs_set7P + ISNULL(Spoiler_prijs, '0') + ISNULL(Codering_prijs, '0') + ISNULL(Uitbreidingsset_prijs, '0')) / 10, 0) 
                         * 10 AS geplaatstorig, ROUND((prijs_vast * 1.21 + werk_vast + prijs_set7P + ISNULL(Spoiler_prijs, '0') + ISNULL(Codering_prijs, '0') + ISNULL(Uitbreidingsset_prijs, '0')) / 10, 0) * 10 AS geplaatstvast, checkvast, checkorig, 
                         checkes, Cataloog_ID
FROM            dbo.Cataloog

Answer 1

I don't think the problem is in saving once I clear the cell I can't select anything else.
Something has to be filled in first before I can continue.
Could this be because the cell is used in a query calculation and therefore cannot be empty?

Answer 2

it's a winform and i use this code to save the data.

 Function Save_cataloog() As Boolean
        Try
            Me.Validate()
            Me.CataloogBindingSource.EndEdit()
            Me.CataloogTableAdapter.Update(Me.CataloogDataSet.Cataloog)

            Return True
        Catch ex As Exception
            MsgBox(ex.ToString)
            Return False
        End Try
    End Function

Answer 3

If you are using Management Studio, then try pressing <Ctrl+0> to empty the numeric nullable cell.