WP8 / C＃/ SQLite：獲取最后插入的ID？

Question

使用WP8的SQLite讓我瘋狂。 :(

我想做的就是檢索最后插入的id的值...

我有：

class ShoppingItem
{
  [SQLite.PrimaryKey, SQLite.AutoIncrement]
  public int Id {get; set;}
  public string Name {get; set;}
  public string Shop {get; set;}
  public bool isActive {get; set;}
}

好吧，使用過的SQLiteConnection對象及其Table<ShoppingItem>似乎都不包含包含最后一個ID的適當成員。

所以我試着這樣做：

private int GetLastInsertedRowID()
{
  int Result = -1;
  using (var db = new SQLiteConnection(m_DatabasePath)) {
    Result = db.ExecuteScalar<int>("SELECT last_insert_rowid();");
  }
  return Result;
}

但是這個函數總是返回0 。 :(但是當我讀取ShoppingItem所有條目時，他們的ID都有值！= 0。

所以我的問題是：我怎樣才能檢索最后插入的id？

PS：將SQL查詢更改為SELECT last_insert_rowid() FROM ShoppingItem; 給出了相同的結果。

PPS： 在C＃中使用SQLite.NET獲取最后一個插入ID的解決方案無法編譯，顯然使用的是舊版本的SQLite，具有完全不同的API

Answer 1

您的SELECT last_insert_rowid()調用不起作用，因為您在另一個數據庫連接中運行它。

無論如何，您應該只是從插入的ShoppingItem對象中讀取ID，如下所示：

var si = new ShoppingItem() {
  Name = anItem,
  Shop = aShop,
  isActive = aIsActive,
};
db.Insert(si);
return si.Id;

Answer 2

這是我檢索最后插入項目的ID。 提供的代碼段使用SQLite 3.7.XX（ SQLite ）在我的Windows 8應用程序中運行。

    public class ExpenseDataMapper
    {
        SQLiteConnection connection;

        /// <summary>
        /// Constructor
        /// </summary>
        public ExpenseDataMapper()
        {
            connection = new SQLiteConnection(StaticResources.DATABASE_PATH_NAME);

            connection.CreateTable<FinancialListBoxExpenseItem>();
        }

        /// <summary>
        /// Method #1: Inserts an FinancialListBoxExpenseItem into Database
        /// </summary>
        /// <param name="item"></param>
        /// <returns>Primary key of inserted item</returns>
        public int insertExpenseItem(FinancialListBoxExpenseItem item)
        {
            int primaryKey = 0;
            connection.RunInTransaction(() =>
                            {
                                connection.Insert(item);
                                primaryKey = item.expenseID;
                            });

            return primaryKey;
        }

    /// <summary>
    /// Method #2: Inserts an FinancialListBoxExpenseItem into Database
    /// </summary>
    /// <param name="item"></param>
    /// <returns>Primary key of inserted item</returns>
    public int insertExpenseItem2(FinancialListBoxExpenseItem item)
    {
        int primaryKey = 0;
        connection.RunInTransaction(() =>
                        {
                            connection.Insert(item);
                            primaryKey = connection.ExecuteScalar<int>("SELECT last_insert_rowid()");
                        });

        return primaryKey;
    }
}

FinancialListBoxItem類中的id屬性如下所示：

 public class FinancialListBoxExpenseItem : Money.Common.BindableBase
    {

        private int _expenseID = 0;
        [AutoIncrement, PrimaryKey]
        public int expenseID
        {
            get
            {
                return _expenseID;
            }

            set
            {
                this.SetProperty<int>(ref _expenseID, value);
            }
        }
}

我建議你為你的pk列'Id'選擇一個不同的名字。 我不知道Id是否類似於內部關鍵字。 編輯：好吧，它不是一個SQLite關鍵字，但無論如何id不是一個正確的名稱（來源： SQLite關鍵字 ）

Answer 3

   public List<int[]> CreateSymbolByName(string SymbolName, bool AcceptDuplicates)
    {
        if (! AcceptDuplicates)  // check if "AcceptDuplicates" flag is set
        {
            List<int[]> ExistentSymbols = GetSymbolsByName(SymbolName, 0, 10); // create a list of int arrays with existent records
            if (ExistentSymbols.Count > 0) return ExistentSymbols; //(1) return existent records because creation of duplicates is not allowed
        }
        List<int[]> ResultedSymbols = new List<int[]>();  // prepare a empty list
        int[] symbolPosition = { 0, 0, 0, 0 }; // prepare a neutral position for the new symbol
        try // If SQL will fail, the code will continue with catch statement
        {
            //DEFAULT und NULL sind nicht als explizite Identitätswerte zulässig
            string commandString = "INSERT INTO [simbs] ([En]) OUTPUT INSERTED.ID VALUES ('" + SymbolName + "') "; // Insert in table "simbs" on column "En" the value stored by variable "SymbolName"
            SqlCommand mySqlCommand = new SqlCommand(commandString, SqlServerConnection); // initialize the query environment
                SqlDataReader myReader = mySqlCommand.ExecuteReader(); // last inserted ID is recieved as any resultset on the first column of the first row
                int LastInsertedId = 0; // this value will be changed if insertion suceede
                while (myReader.Read()) // read from resultset
                {
                    if (myReader.GetInt32(0) > -1) 
                    {
                        int[] symbolID = new int[] { 0, 0, 0, 0 };
                        LastInsertedId = myReader.GetInt32(0); // (2) GET LAST INSERTED ID
                        symbolID[0] = LastInsertedId ; // Use of last inserted id
                        if (symbolID[0] != 0 || symbolID[1] != 0) // if last inserted id succeded
                        {
                            ResultedSymbols.Add(symbolID);
                        }
                    }
                }
                myReader.Close();
            if (SqlTrace) SQLView.Log(mySqlCommand.CommandText); // Log the text of the command
            if (LastInsertedId > 0) // if insertion of the new row in the table was successful
            {
                string commandString2 = "UPDATE [simbs] SET [IR] = [ID] WHERE [ID] = " + LastInsertedId + " ;"; // update the table by giving to another row the value of the last inserted id
                SqlCommand mySqlCommand2 = new SqlCommand(commandString2, SqlServerConnection); 
                mySqlCommand2.ExecuteNonQuery();
                symbolPosition[0] = LastInsertedId; // mark the position of the new inserted symbol
                ResultedSymbols.Add(symbolPosition); // add the new record to the results collection
            }
        }
        catch (SqlException retrieveSymbolIndexException) // this is executed only if there were errors in the try block
        {
            Console.WriteLine("Error: {0}", retrieveSymbolIndexException.ToString()); // user is informed about the error
        }

    CreateSymbolTable(LastInsertedId); //(3) // Create new table based on the last inserted id
    if (MyResultsTrace) SQLView.LogResult(LastInsertedId); // log the action
    return ResultedSymbols; // return the list containing this new record
}