ADO.NET Entity Framework 试水——并发[3]

当前数据库情况如图所示

第一步在概念模型设计器里按照图所示分别把NotebookBrand和NotebookType属性的Concurrency Mode设置为Fixed

然后我们写一段代码来模拟一个并发沖突的情况

Create object context

Dim objContext As New NbWhEntities()

Dim objContext As New NbWhEntities()

Query the same record as entities

Dim laptop = (From aLaptop In objContextNotebook _

Where aLaptopId = _

Select aLaptop)FirstOrDefault()

Dim laptop = (From aLaptop In objContextNotebook _

Where aLaptopId = _

Select aLaptop)FirstOrDefault()

Modify the entity

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