I am trying to create a C# data generator for oracle database. Though I have run into some problems. I am getting ORA-26010 error message which is:

A column which is NOT NULL in the database is not being loaded and will cause every row to be rejected.

I didn't have that problem with previous tables and spend hours already to find solution.

This is how it looks in the code:

 private static DataTable BuildMagazynTable(int b)
    {
        var magazynTable = new DataTable();
        magazynTable.Columns.Add("ID");
        magazynTable.Columns.Add("NAZWA_MAGAZYNU");
        magazynTable.Columns.Add("MIASTO");
        magazynTable.Columns.Add("ULICA");
        magazynTable.Columns.Add("NR_LOKALU");

        for (int i = 1; i <= b; i++)
        {
            var ar = magazynTable.NewRow();
            ar["ID"] = null;
            ar["NAZWA_MAGAZYNU"] = "Nazwa Magazynu" + i;
            ar["MIASTO"] = "Miasto" + i;
            ar["ULICA"] = "Ulica" + i;
            ar["NR_LOKALU"] = "Nr lokalu" + i;

            magazynTable.Rows.Add(ar);
        }
        return magazynTable;
    }

And there is how I created the table in oracle database:

CREATE TABLE magazyn (

id                NUMBER GENERATED by default on null as IDENTITY,
Nazwa_magazynu  VARCHAR2(15) NOT NULL,
miasto            VARCHAR2(15) NOT NULL,
ulica             VARCHAR2(15) NOT NULL,
Nr_lokalu      VARCHAR2(15) NOT NULL);
ALTER TABLE magazyn ADD CONSTRAINT magazyn_pk PRIMARY KEY ( id );

And there is screen from SQL Developer:

I am using Oracle.ManagedDataAccess with bulkcopy to send data to database.