在開始修改記錄之前是否有辦法鎖定一條記錄？

Question

在開始修改記錄之前是否有辦法鎖定一條記錄？

string stOpenConn = new FbConnectionStringBuilder { 
    Database = stPathFilename, 
    UserID = stUserID, 
    Password = stPassword, 
    ServerType = FbServerType.Embedded, 
    ClientLibrary = stCLIENT_LIBRARY 
}.ToString(); 

try { 
    using(FbConnection fbConn = new FbConnection(stOpenConn)) { 
     fbConn.Open(); 

     string stCmd = "UPDATE " + stTableName + " SET " + liststFieldNamesNoKeyID[0] + " = @p0"; 
     for (int iii = 1; iii < liststFieldNamesNoKeyID.Count(); iii++) 
      stCmd += ", " + liststFieldNamesNoKeyID[iii] + " = @p" + iii.ToString(); 
     stCmd += " WHERE" + stFieldKeyID + "= @p" + liststFieldNamesNoKeyID.Count().ToString(); 

     FbTransaction fbTransaction = fbConn.BeginTransaction(); 
     using (FbCommand fbCmd = new FbCommand(stCmd, fbConn, fbTransaction)) { 
      for (int iii = 0; iii < liststFieldNamesNoKeyID.Count(); iii++) { 
       string stPlaceHolder = "@p" + (iii).ToString(); 
       string stValue = liststNewValuesNoKeyID[iii]; 
       fbCmd.Parameters.AddWithValue(stPlaceHolder, stValue); 
      } 
      int iKeyID = Convert.ToInt32(stKeyID); 
      fbCmd.Parameters.AddWithValue("@p" + liststFieldNamesNoKeyID.Count().ToString(), iKeyID); 
      fbCmd.ExecuteNonQuery(); 
      fbTransaction.Commit(); 
     }//using 
    }//using 
}//try 

然後修改後發佈完成？

我認爲記錄鎖定發生在連接打開後...在BeginTransaction之前...並在fbTransaction.Commit之後釋放記錄鎖定。

Answer 1

根據你想怎麼做，你可以使用（小心）選擇的「WITH LOCK」子句，這將變成悲觀鎖（這就是爲什麼你需要謹慎使用它）。更多信息，請參閱https://firebirdsql.org/refdocs/langrefupd21-notes-withlock.html 「愚蠢」更新也會作爲悲觀鎖定。