How to merge only the missing rows

I have this code.

However I got an exception in the merge line:

Failed to enable constraints. One or more rows contain values violating non-null
I would like a simple way, that it merges the missing rows only, if there are rows that already exist, it shouldn't try to copy them

Thanks

public UC010_WizardStepBusinessParkDataSet GetBusinessParkData(Int32 businessParkID)
        {
            // Init
            UC010_WizardStepBusinessParkDataSet dataSet = new UC010_WizardStepBusinessParkDataSet();
            View_BuildingModule_UC010_BusinessPark_Wizard_GetBusinessParkData vwBusPark = new View_BuildingModule_UC010_BusinessPark_Wizard_GetBusinessParkData();
            View_BuildingModule_UC010_BusinessPark_Wizard_GetBusinessParkPortfolioManagerData vwBusParkPortfolioMngr = new View_BuildingModule_UC010_BusinessPark_Wizard_GetBusinessParkPortfolioManagerData();

            vwBusPark.Where.BusinessParkID.Value = businessParkID;
            vwBusParkPortfolioMngr.Where.BusinessParkID.Value = businessParkID;

             if (vwBusPark.Query.Load())
                dataSet.BusinessPark.Merge(vwBusPark.toDataTable(), true, System.Data.MissingSchemaAction.Ignore);

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