使用xamarin ios的构建之间不存在数据库

sqlite文件是在“个人”文件夹中创建的,并且在构建之间保留,但是当我运行应用程序时,我在上一个调试会话中创建的表格消失了吗？

在我的代码中,在检查文件是否存在之后,我使用sqliteconnection连接并创建一个表,并从命令对象中插入一个带有executenonquery方法的行.虽然在相同的上下文中我可以使用第二个命令对象查询表,但如果我停止调试器并重新启动表,我走了？

我应该将文件放在不同的文件夹中,是用Xamarin还是ios设置来保存表格？我无意中在sqlite中使用临时表或可能是什么问题？

注意：到目前为止,我只使用Xamarin的启动版本并在iphone模拟器上进行调试.

public class BaseHandler
{
     private static bool DbIsUpToDate { get; set; }

     const int DB_VERSION = 1;    //Created DB

     const String db_name = "mydb.db3";
     protected const String CNN_StriNG = "Data source=" + db_name + ";Version=3";

     public BaseHandler ()
     {
         //No need to validate database more than once on each restart.
         if (DbIsUpToDatE)
             return;

         checkAndCreateDatabase(db_name);

         int userVersion = GetUserVersion();
         updateDBToVersion(userVersion);

         DbIsUpToDate = true;
    }

    int GetUserVersion()
    {
         int version = 0;

         using (var cnn = new sqliteConnection(CNN_StriNG)) 
         {
             cnn.open();

             using (var cmd = cnn.CreateCommand())
             {
                 cmd.CommandText = "create table UVERSION (VERSION IntegeR);" +
                                   "INSERT INTO UVERSION (VERSION) VALUES(1);";
                 cmd.ExecuteNonQuery();
             }

             using (var cmd = cnn.CreateCommand())
             {
                 cmd.CommandText = "SELECT VERSION FROM UVERSION;";
                 var pragma = cmd.ExecuteScalar();
                 version = Convert.ToInt32((long)pragma);
             }
        }

        return version;
    }


    void updateDBToVersion(int userVersion)
    {
         //Prepare the sql statements depending on the users current verion
        var sqls = new List<String> ();

         if (userVersion < 1) 
        {
             sqls.Add("create table IF NOT EXISTS myTABLE ("
                     + " ID INTEGER PRIMARY KEY,"
                     + " @R_272_4687@T,"
                     + " Desc text "
                     + ");");
        }

         //Execute the update statements
        using (var cnn = new sqliteConnection(CNN_StriNG)) 
        {
             cnn.open();

             using (var trans = cnn.begintransaction(System.Data.isolationLevel.ReadCoR_967_11845@mitted))
             {
                foreach(String sql in sqls) 
                {
                    using (var cmd = cnn.CreateCommand())
                    {
                        cmd.CommandText = sql;
                        cmd.ExecuteNonQuery();
                    }
                }

                 trans.Commit();

                 //SetUserVersion(DB_VERSION);
            }

         }
     }

    protected String GetDBPath (String dbName)
    {
         // get a reference to the documents folder
        var documents = Environment.GetFolderPath(Environment.SpecialFolder.Personal);

         // create the db path
        String db = Path.Combine (documents,dbName);

         return db;
    }

    protected void checkAndCreateDatabase (String dbName)
    {
         var dbPath = GetDBPath(dbName);

         // determine whether or not the database exists
         bool dbExists = File.Exists(dbPath);

         if (!dbExists) 
            sqliteConnection.CreateFile(dbPath);
    }
 }

同样,我的问题是,每次运行调试器时,它都会运行GetUserVersion,但会话之间的表UVERSION不会持久存在. “File.Exists(dbPath)”返回true,因此不运行CreateFile.为什么db是空的？