Xamarin格式：在sqlite中插入新数据时，删除旧数据

Question

我在sqllite中插入数据，通常我有图像，我正在以字节为单位插入这些图像，但是当插入第一个图像时，插入第二个图像时插入很好，它删除所有数据并插入新的图像，这是我的代码

FileData fileData = await CrossFilePicker.Current.PickFile();
if (fileData == null)
    return; // user canceled file picking

string fileName = fileData.FileName;

string contents = fileData.DataArray.ToString();

try
{
    var item = new customer_Files { delete6m = document6mtoggle.IsToggled, filecontent = fileData.DataArray, file_name = fileName, date6m = DateTime.Today.AddMonths(6) };

    await _connection.InsertAsync(item);
}
catch (Exception ex)
{
    await DisplayAlert("", ex.Message, "ok");
}   

Android

namespace NavigationMenu.Droid
{
    public class SQLiteDb : ISQLiteDb
    {
        public SQLiteAsyncConnection GetConnection()
        {
            var documentsPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
            var path = Path.Combine(documentsPath, "MySQLite.db3");

            return new SQLiteAsyncConnection(path);
        }
    }
}

PCL

protected async override void OnAppearing()
        {
            await _connection.CreateTableAsync<LocalNote>();
            await _connection.CreateTableAsync<InvoiceDetail>();
            await _connection.CreateTableAsync<Invoice>();
            await _connection.CreateTableAsync<customer_Files>();

            base.OnAppearing();

        }
public AddCustomerDetail()
        {
            InitializeComponent();

            _connection = DependencyService.Get<ISQLiteDb>().GetConnection();

        }