国产精品高清全国免费观看,欧美一级视频免费观看,久久精品香蕉

使用存儲過程，在操作數據庫時開啟事務，避免并發時同時操作造成數據重復

mybatis+mysql 使用存儲過程生成流水號的實現代碼

									CREATE DEFINER=`root`@`localhost` PROCEDURE `GetSerialNo`(IN tsCode VARCHAR(50),OUT result VARCHAR(200) )

									BEGIN

									 DECLARE tsValue VARCHAR(50); 

									 DECLARE tdToday VARCHAR(20);  

									 DECLARE nowdate VARCHAR(20);  

									 DECLARE tsQZ  VARCHAR(50); 

									 DECLARE t_error INTEGER DEFAULT 0; 

									 DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET t_error=1; 

									 START TRANSACTION; 

									  /* UPDATE sys_sno SET sValue=sValue WHERE sCode=tsCode; */

									  SELECT sValue INTO tsValue FROM sys_sno WHERE sCode=tsCode; 

									  SELECT sQz INTO tsQZ FROM sys_sno WHERE sCode=tsCode ; 

									 -- 因子表中沒有記錄，插入初始值  

									  IF tsValue IS NULL THEN

									   SELECT CONCAT(DATE_FORMAT(NOW(),'%y%m'),'0001') INTO tsValue; 

									   UPDATE sys_sno SET sValue=tsValue WHERE sCode=tsCode ; 

									   SELECT CONCAT(tsQZ,tsValue) INTO result; 

									  ELSE    

									   SELECT SUBSTRING(tsValue,1,4) INTO tdToday; 

									   SELECT CONVERT(DATE_FORMAT(NOW(),'%y%m'),SIGNED) INTO nowdate;

									   -- 判斷年月是否需要更新

									   IF tdToday = nowdate THEN

									    SET tsValue=CONVERT(tsValue,SIGNED) + 1; 

									   ELSE

									    SELECT CONCAT(DATE_FORMAT(NOW(),'%y%m') ,'0001') INTO tsValue ; 

									   END IF; 

									   UPDATE sys_sno SET sValue =tsValue WHERE sCode=tsCode; 

									   SELECT CONCAT(tsQZ,tsValue) INTO result; 

									  END IF; 

									  IF t_error =1 THEN

									  ROLLBACK; 

									  SET result = 'Error'; 

									  ELSE

									  COMMIT; 

									  END IF; 

									  SELECT result ;  

									END;

									dao

									Integer getFaultNo(Map<String, String> parameterMap);

xml

									<update id="getFaultNo" parameterMap="getFaultMap" statementType="CALLABLE">

									  CALL GetSerialNo(?,?)

									 </update>

									 <!--

									  parameterMap.put("tsCode", 0);

									  parameterMap.put("result", -1);

									  -->

									 <parameterMap type="java.util.Map" id="getFaultMap">

									  <parameter property="tsCode" mode="IN" jdbcType="VARCHAR"/>

									  <parameter property="result" mode="OUT" jdbcType="VARCHAR"/>

									 </parameterMap>

調用

									Map<String, String> parameterMap = new HashMap<String, String>();

									  parameterMap.put("tsCode", "a");

									  parameterMap.put("result", "-1");

									  faultMapper.getFaultNo(parameterMap);

									  // insert 故障日志 (主表)

									  if (!parameterMap.get("result").equals("-1") && 

									    !parameterMap.get("result").equals("Error")) {

									   //成功

									  } else {

									   throw new RuntimeException();

									  }