Making sense of database responses

We're nearing the end of a large system for the lovely people over at Consolidated Communications Management Ltd and we've just come across a nice idea to make sense of database responses. Typically in the past we've simply returned -1/0 for failure and a positive integer (usually an id) of it was successful. The new method should add a little more conformity to our code. We already use a common Database Access Layer which handles the opening/closing of our connection, adding parameters etc but I’ve just added an enum with the common database responses, thought it may be of use to others:

public enum DatabaseResponse

{...}

{
    Success = 0,
    Init = -1,
    Found = -2,
    NotFound = -3,
    Duplicate = -4
}

This should cover the common responses from our database however to make it a little more futureproof we'll keep -1 through to -10 reserved for this data level and then start more specific responses from -11 (i.e. BadPassword).

Using it is simple (this is not real code before you ask!):

public bool Save()

{...}

{
    DatabaseLayer DBLayer = new DatabaseLayer();

    //Check whether we should be saving or inserting this record
    if (this.Id == (int)DatabaseLayer.DatabaseResponse.Init)

    {...}

    {
        //The Id's set to initialised only so insert
        //The create method simply inserts the values into the database and returns
        //either the Id of the newly inserted record or our database response
        this.Id = DBLayer.Create(this);

        if (this.Id >= (int)DatabaseLayer.DatabaseResponse.Success)

        {...}

        {
            //The insert was a success
            return true; 
        }

        else

        {...}

        {
            //The insert failed for some reason -you could throw an error 
            //to catch or simply bubble the response upto to the code behind layer
            return false; 
        }

    }

    else

    {...}

    {
        //When updating the record don't use the Id to store the response, instead
        //throw it into a temp object and use that so the Id's still stored in the object
        int response = DBLayer.Update(this);

        if (response == (int)DatabaseLayer.DatabaseResponse.Success)
            return true; //All's ok
        else
            return false; //Something went wrong -it could be the item wasn't found etc
    }

}