validation on import from Excel to Database using ADO.net

Question

I need to Append data from Excel to Database so I need to check for validation in Excel columns like if dr[0] is number or not and if any row in Excel is repeated in the database skip it and add only new records:

MaamoonKhalidIssueEntities db = new MaamoonKhalidIssueEntities();
                    foreach (DataTable table in result.Tables)
                    {
                        foreach (DataRow dr in table.Rows)
                        {
                            Person addtable = new Person()
                            {

                                nparent =Convert.ToInt32(dr[0]),
                                ncode = Convert.ToString(dr[1]),
                                nname = Convert.ToString(dr[2])

                            };
                        db.People.Add(addtable);
                        }

I Can't check on dr[0] because its object

Answer 1

You can write a ValidateNewPerson-Method. This method tries to fetch a person with the same ncode from the DB. If this succeeds, the record is not valid, if not, the person can be added:

public bool ValidateNewPerson(Person newPerson, MaamoonKhalidIssueEntities db)
{
    var dbPerson = db.People.Where(e => e.ncode == newPerson.ncode).FirstOrDefault();
    if (dbPerson == null)
        return true;
    else
        return false;
}

Now you can call this method in your foreach:

foreach (DataRow dr in table.Rows)
{
    Person addtable = new Person()
    {
        nparent =Convert.ToInt32(dr[0]),
        ncode = Convert.ToString(dr[1]),
        nname = Convert.ToString(dr[2])
    };
    if (ValidateNewPerson(addtable, db))
        db.People.Add(addtable);
 }        

If you want to use a Linq-Method, you can use Any, to request if any record in your db matches your criteria:

foreach (DataRow dr in table.Rows)
{
    Person addtable = new Person()
    {
        nparent =Convert.ToInt32(dr[0]),
        ncode = Convert.ToString(dr[1]),
        nname = Convert.ToString(dr[2])
    };
    if (!db.People.Any(p => p.ncode == addtable.ncode))
        db.People.Add(addtable);
 }