為了加深對EF特性的了解so寫了一些測試代碼測試結果也許對實際項目沒什麼用處但是對理解EF的相關機制還是有一定幫助的本文可能會不定期更新(加入新的測試用例==)
一事務
直接看代碼
所有SaveChange包裹在一個TransactionScope裡面
[TestMethod]
public void TestMethod()
{
using (var entities = new SysProcessEntities())
{
using (TransactionScope scope = new TransactionScope())
{
try
{
var test = entitiesSysUserWhere(o => oOrganizationID == )ToList();
var test = entitiesSysRoleToList();
test[]Code = admin;
test[]Name = dddd;
entitiesSaveChanges();
test[]Code = admin;
test[]Name = 全功能;
entitiesSaveChanges();
scopeComplete();
}
catch (Exception e)
{
}
}
}
}
結果
在的基礎上去掉TransactionScope
[TestMethod]
public void TestMethod()
{
using (var entities = new SysProcessEntities())
{
var test = entitiesSysUserWhere(o => oOrganizationID == )ToList();
var test = entitiesSysRoleToList();
test[]Code = admin;
test[]Name = dddd;
entitiesSaveChanges();
test[]Code = admin;
test[]Name = 全功能;
entitiesSaveChanges();
}
}
結果
注釋掉的第行和第行檢查單獨的一條語句是否自帶事務
[TestMethod]
public void TestMethod()
{ using (var entities = new SysProcessEntities())
{
var test = entitiesSysUserWhere(o => oOrganizationID == )ToList();
var test = entitiesSysRoleToList();
//test[]Code = admin;
test[]Name = dddd;
entitiesSaveChanges();
//test[]Code = admin;
test[]Name = 全功能;
entitiesSaveChanges();
}
}
結果
直接寫Sqlupdate [SysProcess][dbo][SysRole] set [name]=全功能 where ID=在查詢分析器中執行結果
將改為跨數據庫
[TestMethod]
public void TestMethod()
{
using (TransactionScope scope = new TransactionScope())
{
try
{
using (var entities = new SysProcessEntities())
{
var test = entitiesSysUserWhere(o => oOrganizationID == )ToList();
var test = entitiesSysRoleToList();
test[]Code = admin;
test[]Name = dddd;
entitiesSaveChanges();
test[]Code = admin;
test[]Name = 全功能;
entitiesSaveChanges();
}
using (var entities = new DistributionEntities())
{
var test = entitiesVIPCardToList();
test[]Sex = true;
entitiesSaveChanges();
}
scopeComplete();
}
catch (Exception e)
{
string msg = eMessage;
}
}
}
結果
於是整個世界美好了……
二AsNoTracking
注意AsNoTracking要寫在最終返回數據的那行代碼中才有用看代碼
[TestMethod]
public void TestMethod()
{
using (var entities = new SysProcessEntities())
{
var ubs = entitiesUserBrandAsNoTracking();
var obs = entitiesOrganizationBrandWhere(ob => obOrganizationID == )AsNoTracking();
var brands = from ub in ubs
from ob in obs
where ubBrandID == obBrandID
select ubBrandID;
var test = entitiesProBrandWhere(b => brandsContains(bID))ToList();
AssertAreEqual(EntityStateDetached entitiesEntry(test[])State);
}
}
結果
sousing之中應該這麼寫
var ubs = entitiesUserBrand;
var obs = entitiesOrganizationBrandWhere(ob => obOrganizationID == );
var brands = from ub in ubs from ob in obs where ubBrandID == obBrandID select ubBrandID;
var test = entitiesProBrandWhere(b => brandsContains(bID))AsNoTracking()ToList();
AssertAreEqual(EntityStateDetached entitiesEntry(test[])State);
三DbSetLocal
繼續看代碼
public void TestMethod()
{
var entities = new SysProcessEntities();
var t = entitiesProBoduanToList();
var t = entitiesProBoduanToList();
AssertAreEqual(t[]t[]);
}
大家以為t[]是否等於t[]?答案是true可是作為引用類型我並沒有重載它的Equals方法照理應該為false才對呀修改下測試代碼
public void TestMethod()
{
var entities = new SysProcessEntities();
var t = entitiesProBoduanToList();
var t = entitiesProBoduanToList();
string name = t[]Name;
t[]Name = 隨便取個名用來測試;
AssertAreEqual(name t[]Name);
}
結果
可知t[]和t[]指向的是同一個對象即t和t指向同一個數組地址也就是entitiesProBoduanLocal指向的地址不過數據庫中仍執行了兩次取數操作
then加入AsNoTracking試試看
public void TestMethod(){ var entities = new SysProcessEntities();
var t = entitiesProBoduanAsNoTracking()ToList();
var t = entitiesProBoduanAsNoTracking()ToList();
string name = t[]Name; t[]Name = 隨便取個名用來測試;
AssertAreEqual(name t[]Name); //truet的更改不影響t表明t和t指向不同地址}
此時entitiesProBoduanLocalCount為
public void TestMethod()
{
var entities = new SysProcessEntities();
var t = entitiesProBoduanFirstOrDefault();
var count = entitiesProBoduanLocalCount;//
var t = entitiesProBoduanToList();
var count = entitiesProBoduanLocalCount;// }
將第行和第行換下位置
public void TestMethod()
{
var entities = new SysProcessEntities();
var t = entitiesProBoduanToList();
var count = entitiesProBoduanLocalCount;//
var t = entitiesProBoduanFirstOrDefault();
var count = entitiesProBoduanLocalCount;//
}
public void TestMethod() {var entities = new SysProcessEntities(); var t = entitiesProBoduanFirstOrDefault();var count = entitiesProBoduanLocalCount;//var t = entitiesProBoduanToList();var count = entitiesProBoduanLocalCount;// }
將第行和第行換下位置
public void TestMethod() {var entities = new SysProcessEntities();var t = entitiesProBoduanToList();var count = entitiesProBoduanLocalCount;// var t = entitiesProBoduanFirstOrDefault();var count = entitiesProBoduanLocalCount;// }
From:http://tw.wingwit.com/Article/program/net/201311/13465.html
