"Constraint" Exception while inserting data into a database.

Hi,

I am adding a set of data (ex, name, age, mobile etc.) into my database. Whenever I try to enter it the first time its successful. When I try to add after that, I get a constraint exception because I don't change the mobile no which is the primary key. I have written the code in 'try-catch' but I am unable to catch the exception. 

 public bool Local_LoadData()
        {
                        using (var db = new SQLite.SQLiteConnection(App._DBPath))
            {
                db.CreateTable<Aadhar_Info>();
                try
                {
                    db.RunInTransaction(() =>
                    {
                        db.Insert(new Aadhar_Info()
                        {
                            //1st page data
                            UID = App.UID,
                            FName = App.FName, 
                            LName = App.LName,  // set UI parameters
                            MName = App.MName, // set UI parameters                            
                            DateOfBirth = App.UI_DOB,
                            Gender = App.UI_Gender,
                            EmailID = App.EmailID,
                            CareOF = App.CareOF,
                            House = App.House,
                            Street = App.Street,
                            LandMark =App.LandMark,
                            Locality = App.Locality,
                            PostOffice = App.PostOffice,
                            Mobile = App.Mobile,
                            VillageTownCity =App.VillageTownCity,
                            SubDistrict = App.SubDistrict,
                            District = App.District,
                            State = App.State,
                            PinCode = App.PinCode,
                            //2nd page data
                            PAN_GIRNo = App.PAN_GIRNo,
                            MaritialStatus = App.UI_MatitalStatus,
                            Nationality= App.Nationality,
                            ResidentialStatus =App.ResidentialStatus,
                            PermanentAddress1= App.PermanentAddress1,
                            PermanentAddress2= App.PermanentAddress2,
                            PermanentAddress3= App.PermanentAddress3,
                            PermanentAddress4= App.PermanentAddress4,
                            AlternateContactNo=App.AlternateContactNo,
                            OfficeAddress1= App.OfficeAddress1,
                            OfficeAddress2= App.OfficeAddress2,
                            OfficeAddress3=App.OfficeAddress3,
                            OfficeAddress4=App.OfficeAddress4,
                            LandlineNo= App.LandlineNo,
                            ExtensionNo= App.ExtensionNo,
                            Occupation= App.Occupation,
                            Designation= App.Designation  

                                                     
                           
                        });
                    });
                }
                   
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine("tp local Duplicate Entry Restricted");
                    return false;

                }
            }