SqlCommand command = new SqlCommand("SELECT ContactID, FirstName, LastName FROM dbo.Contact FOR XML AUTO, XMLDATA", SqlConn); 此方法还可用于检索单行、单列结果集。 在这种情况下,如果返回了多行,该方法 EndExecuteXmlReader 会将XmlRe
; SqlCommand command =newSqlCommand(commandText, connection); connection.Open(); IAsyncResult result = command.BeginExecuteReader( CommandBehavior.CloseConnection);// Although it is not necessary, the following code// displays a counter in the console window, indicating that// the main ...
importmysql.connectordefexecute_transaction(sql_commands):conn=mysql.connector.connect(user='user',password='password',database='dbname')cursor=conn.cursor()try:cursor.execute("BEGIN;")forcommandinsql_commands:cursor.execute(command)cursor.execute("COMMIT;")exceptExceptionase:conn.rollback()print("Er...
lex->sql_command= SQLCOM_BEGIN; /* READ ONLY and READ WRITE are mutually exclusive. */ if (($3 & MYSQL_START_TRANS_OPT_READ_WRITE) && ($3 & MYSQL_START_TRANS_OPT_READ_ONLY)) { YYTHD->syntax_error(); MYSQL_YYABORT; } lex->start_transaction_opt= $3; } ; 上面是解析 START ...
private SqlConnection connection; private static string GetConnectionString() { // To avoid storing the connection string in your code, // you can retrieve it from a configuration file. // If you have not included "Asynchronous Processing=true" in the // connection string, the ...
有了OPTION_BEGIN标志,MySQL 就不会每次执行完一条 SQL 语句就提交事务,而是需要用户发起 commit 语句才提交事务,这样的事务就可以执行多条 SQL 了。 3. 总结 一句话总结:BEGIN 语句执行过程中,要做的事情就是辞旧(提交老事务)迎新(准备新事务),并不会马上启动一个新事务。
三、慢SQL MySQL执行原理 解析:词法解析->语法解析->逻辑计划->查询优化->物理执行计划 检查是否存在可用查询缓存结果,如果没有或者缓存失效,则调用mysql_execute_command执行。 执行:检查用户、表权限->表上加共享数据->取数据到query cache->取消共享读锁 ...
lex->sql_command= SQLCOM_BEGIN; /* READ ONLY and READ WRITE are mutually exclusive. */ if (($3 & MYSQL_START_TRANS_OPT_READ_WRITE) && ($3 & MYSQL_START_TRANS_OPT_READ_ONLY)) { YYTHD->syntax_error(); MYSQL_YYABORT; }
lex->sql_command= SQLCOM_BEGIN; /* READ ONLY and READ WRITE are mutually exclusive. */ if (($3 & MYSQL_START_TRANS_OPT_READ_WRITE) && ($3 & MYSQL_START_TRANS_OPT_READ_ONLY)) { YYTHD->syntax_error(); MYSQL_YYABORT; }
{try{intcount =0; SqlCommand command =newSqlCommand(commandText, connection); connection.Open(); IAsyncResult result = command.BeginExecuteNonQuery();while(!result.IsCompleted) { Console.WriteLine("Waiting ({0})", count++);// Wait for 1/10 second, so the counter// does not co...