Insert missing records in a list with LINQ

We have a table with periods, and other child tables with these periods and values for combinations of product + location.

Based on selected periods, I would like to add any missing rows in the child tables. I have come up with the following code, which seems to work just fine. But I would like to know if there is a simpler or more efficient way of doing this, since I have to repeat this for a number of tables.

public static void SeedActivityData(int startPeriod, double endPeriod, IList stockStatus)
{
    DAL.EFDbContext dbFilter = new DAL.EFDbContext(0, stockStatus.FirstOrDefault().Product, startPeriod, endPeriod);
    var period = dbFilter.Periods.Select(b => b.PeriodID);
    foreach (var item in stockStatus)
    {
        IEnumerable missingFAF = period.Except(dbFilter.OMS_Forecast_Adjustment.Where(a => a.SiteID == item.SiteID).Select(b => b.PeriodID));

        var modelFAF = db.OMS_Forecast_Adjustment;
        foreach (int periodID in missingFAF)
        {
            var modelItem = new OMS_Forecast_Adjustment { PeriodID = periodID, Product = item.Product, SiteID = item.SiteID, Value = 0 };
            modelFAF.Add(modelItem);
        }

        IEnumerable missingRAF = period.Except(dbFilter.OMS_Receipts_Adjustment.Where(a => a.SiteID == item.SiteID).Select(b => b.PeriodID));

        var modelRAF = db.OMS_Receipts_Adjustment;
        foreach (int periodID in missingRAF)
        {
            var modelItem = new OMS_Receipts_Adjustment { PeriodID = periodID, Product = item.Product, SiteID = item.SiteID, Value = 0 };
            modelRAF.Add(modelItem);
        }

        db.SaveChanges();
    }
}

Looks to me like you should create an Add method to both the OMS_Forecast_Adjustment and OMS_Receipts_Adjustment classes.

you are really adding things to the db all wrong, you are creating new objects in your code when you don't have to, I think that you really want to add items to a collection variable inside your db object.

it should be an InsertRecord method

this:

var modelFAF = db.OMS_Forecast_Adjustment;
    foreach (int periodID in missingFAF)
    {
        var modelItem = new OMS_Forecast_Adjustment { PeriodID = periodID, Product = item.Product, SiteID = item.SiteID, Value = 0 };
        modelFAF.Add(modelItem);
    }

Would turn into this

foreach (int periodID in missingFAF)
{
    db.Insert_OMS_Forcase_Adjustment(periodID, item.prodeuct, item.SiteID, 0);
}

so you actually do your insertion inside of a method in the class that you already have.

This removes the creation of 2 extraneous local variables and puts responsibility where it belongs inside of a method in the object that needs to perform the action.

This can be done on both Foreach Loops

StackExchange Code Review Q#64624, answer score: 2