轉:http://blog.csdn.net/zhaoqianjava/article/details/6924672JPA是基於Java持久化的解決方案,主要是為瞭解決ORM架構的差異,它的出現在某種程度上能夠解決目前ORM架構之間不能夠相容的問題,對開發人員來說,能夠更好的在JPA規範下進行系統開發。 JPA全稱為Java Persistence API ,Java持久化API是Sun公司在Java EE 5規範中提出的Java持久化介面。JPA吸取了目前Java持久化技術的優點,旨在規範、
count():COUNT() 函數返回匹配指定條件的行數。SELECT COUNT(column_name) FROM table_name COUNT(column_name) 函數返回指定列的值的數目(NULL 不計入)1.SELECT COUNT(Customer) AS CustomerNilsen FROM Orders 返回CustomerNilsen表中customer欄位有值的行數的統計數2.SELECT
var select=document.getElementById("id號");var selectedItem = select.options(select.selectedIndex);//擷取當前選中項 var text=selectedItem.text; //選中項的文本 var value=selectedItem.value; //選中項的值select.selectedIndex=0;//設定option的選項indexnew
case whenView Code 1 select (case userid2 when 'CUS0000003017804' then3 '張三'4 when 'CUS0000003017805' then5 '李四'6 else7 '王五'8 end) userid from users a where loginname = 'xxx';View Code 1 select case 2 when
select branchid from branch where parentbranchid='BRA0000000000001' order by branchid第一句只能查詢出父節點是BRA0000000000001的所有子節點select br.branchid from Branch br start with br.branchid = 'BRA0000000000001'connect by Nocycle Prior br.branchid =
假設如下應用:兩張表——使用者表TDefUser(userid,address,phone)和消費表 TAccConsume(userid,time,amount),需要查消費超過5000的使用者記錄。用exists:select * from TDefUserwhere exists (select 1 from TAccConsume where TDefUser.userid=TAccConsume.userid and
//取得checkbox的選擇值View Code 1 var b=document.getElementById("mobileflag").checked;2 if(b == true) {3 b = "Y";4 }else {5 b = "N";6 } 取得全部選中的值:View Code var bol = document.getElementsByName("product");var arr = new
伺服器莫名其妙的報這個錯,之前一直正常,從google擷取解決方案,解決之,記錄如下: 1. Open the ""<OracleHome>/network/admin/listener.ora" file in the host,and you will see: SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = PLSExtProc) (ORACLE_HOME =