c# - 有没有办法在开始修改该记录之前锁定一条记录？

Question

有没有办法在开始修改该记录之前锁定一条记录？

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

修改完成后再发布？

我假设记录锁发生在连接打开之后……在 BeginTransaction 之前……并在 fbTransaction.Commit 之后释放记录锁。

Answer 1

根据您的操作方式，您可以（小心地）使用 select 的“WITH LOCK”子句，这将变成一个悲观锁（这就是为什么在使用它时需要小心的原因）。更多信息请访问https://firebirdsql.org/refdocs/langrefupd21-notes-withlock.html “哑”更新也将充当悲观锁。