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我得到的最新错误是

ERROR: 42P01: relation "dbo.__MigrationHistory" does not exist

但我确信这只是因为早先没有正确设置.

我目前正在尝试设置实体框架4.4代码首先使用Npgsql 2.0.12,我已经完成了以下操作,它似乎至少现在连接到数据库,但是当我做context.saveChanges()时给我上面的错误;

• 更新了.net 2.0.50727的machine.config;

  <add name ="Npgsql Data Provider"invariant ="Npgsql"support ="FF"description =".Postgresql Server的Ne​​t Framework数据提供程序"type ="Npgsql.NpgsqlFactory,Npgsql,Version = 2.0.12.0,Culture = neutral, PublicKeyToken = 5d8b90d52f46fda7"/>

• 将dll添加到项目中

• 将app.config更改为如下所示;

  <configuration>
    <configSections>
      <section name="entityFramework"
        type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection,
        EntityFramework, 
        Version=4.4.0.0, Culture=neutral, 
        PublicKeyToken=b77a5c561934e089" 
        requirePermission="false" />
    </configSections>
    <system.data>
      <DbProviderFactories>
        <remove invariant="Npgsql"></remove>
        <add name="Npgsql Data Provider" 
             invariant="Npgsql" 
             description=".Net Framework Data Provider for Postgresql Server" 
             type="Npgsql.NpgsqlFactory, Npgsql, 
                   Version=2.0.12.0, Culture=neutral, 
                   PublicKeyToken=5d8b90d52f46fda7" />
      </DbProviderFactories>
    </system.data>
    <connectionStrings>
      <add name="DataContext" 
           connectionString="Server=127.0.0.1;Port=5432;Database=postgres;User Id=postgres;Password=*******;CommandTimeout=20;" 
           providerName="Npgsql" />
    </connectionStrings>
  </configuration>
  

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• 传入的数据如下所示

  public …