Question

更新：我删除并重新创建SQL Server后再次迁移，没有错误。所以似乎初始提供程序在模型快照中的某处编码。

更新

我没有意识到这一点，但似乎 Entity Framework Code First Migrations 绑定到特定的DBMS。我在我的演示应用程序SQL Server Compact Edition 4.0中使用，我将它迁移到SQL Server 2014 Express LocalDB。

SQL Server中的数据库架构是正确创建的，但是当我尝试读取或写入数据库时出现以下错误

找不到具有不变名称“System.Data.SqlServerCe.4.0”的ADO.NET提供程序的实体框架提供程序。

我现在不在任何地方使用SQL Server CE，所有NuGet包都已卸载，提供程序已从App.Config中删除。

的app.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="entityFramework"
             type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
             requirePermission="false" />
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 --></configSections>
  <connectionStrings configSource="ConnectionStrings.config" />
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
    <providers>
      <provider invariantName="System.Data.SqlClient"
                type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
</configuration>

ConnectionStrings.config

<?xml version="1.0" encoding="utf-8"?>
<connectionStrings>
  <clear/>
  <add name="CarRentalDb" connectionString="Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=CarRentalDb;Integrated Security=True;multipleactiveresultsets=True" providerName="System.Data.SqlClient"/>
</connectionStrings>

CarRentalDbContext.cs

public class CarRentalDbContext : DbContext
{
    public CarRentalDbContext()
        //only used until development, will not be checked in
        : base(@"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=CarRentalDb;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=True;ApplicationIntent=ReadWrite;MultiSubnetFailover=False")
    {
        Database.SetInitializer(new CarRentalDbInitializer());
    }

    public CarRentalDbContext(string nameOrConnectionString) : base(nameOrConnectionString)
    {
        Database.SetInitializer(new CarRentalDbInitializer());
    }
}

dbo._MigrationHistories

现在，当我删除 dbo._MigrationHistories 表时，错误消失了。我是否需要重新创建迁移以解决SQL Server而不是SQL Server CE？

NewCustomerIsCreated.cs

    [TestMethod]
    public void NewCustomerIsCreated()
    {
        var customerLastName = CustomersLastNameToBeDeleted;

        //Arrange
        var systemUnderTest = new CarRentalBusinessLayer();
        var customerToBeCreated = _autoFixture.Build<CustomerModel>()
                                              .Without(property => property.CustomerId)
                                              .With(property => property.CustomerType, CustomerModel.Consumer)
                                              .With(property => property.LastName, customerLastName).Create();
        var expectedResult = customerToBeCreated;

        //Act
        systemUnderTest.CreateNewCustomer(customerToBeCreated.FirstName, customerToBeCreated.LastName, customerToBeCreated.DateOfBirth, customerToBeCreated.Street, customerToBeCreated.City, customerToBeCreated.Postcode,
            customerToBeCreated.CustomerType);

        //Assert
        Customer actualResult;
        using (var carRentalDbContext = new CarRentalDbContext(_connectionString))
        {
            actualResult = carRentalDbContext.Customers.SingleOrDefault(c => c.LastName == customerLastName);
        }
        Assert.IsTrue(actualResult != null && expectedResult.LastName == actualResult.LastName);
    }

Answer 1

OP的反馈：

重新创建迁移后没有错误。它似乎真的是提供者在模型快照中的某处编码。

原始答案：

是的，绝对必须这样做。这意味着您必须delete __MigrationHistory表上的数据，并且需要recreate。

如果您看到下面的图片，则可以看到ProductVersion列在那里。这是导致运行时错误的原因。

更新：这是EF版本。

 <package id="EntityFramework" version="6.1.3" targetFramework="net461" />

实体框架代码首次迁移是否绑定到特定DBMS？

1 个答案: