我有一个首先使用 EF6 代码的 ASP.NET MVC 站点，它可以完美地针对 MS SQL Server(在本地开发机器和 Azure 网站/SQL 上)运行。现在我将它转移到使用 MySql 5.6 DBS 的生产环境中，这让我很头疼。

我的解决方案分为多个层(网络、 View 模型、模型、数据层接口(interface))，这些层不了解持久性(使用 UnitOfWork 和 GenericRepository)，以及一个引用 EF 程序集的数据项目。

现在我想我应该将我的解决方案分支，将 EF 提供程序从 SQL Server 切换到 MySql。 所以我添加了 MySql.Data.Entities NuGet 包并对 web.config 进行了以下更改:

<entityFramework codeConfigurationType="MySql.Data.Entity.MySqlEFConfiguration, MySql.Data.Entity.EF6">
  <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
  <providers>
    <provider invariantName="MySql.Data.MySqlClient" type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6" />
  </providers>
</entityFramework>

MySql Connector/Net 版本为 MySql.Data 6.8.3.0

我还添加了 [DbConfigurationType(typeof(DbContextConfiguration))] 到我的 DbContext 类和 SetExecutionStrategy(MySqlProviderInvariantName.ProviderName, () => new MySqlExecutionStrategy()); 我的 DbContextConfiguration 类继承自 MySqlEFConfiguration

我能够运行我的代码优先迁移(在 SetHistoryContextFactory(MySqlProviderInvariantName.ProviderName, (conn, schema) => new MySqlHistoryContext(conn, schema)); 的帮助下)并创建数据库架构。

据我所知，数据库模式似乎是正确的。在 SQL Server 中为 nvarchar 的列在 MySql 中为 longtext 或 varchar(取决于实体属性中指定的最大长度)，而 datetime2 为日期时间。

现在，当我运行该应用程序时，出现以下异常:

System.Data.DataException was unhandled by user code
  HResult=-2146233087
  Message=An exception occurred while initializing the database. See the InnerException for details.
  Source=EntityFramework
  StackTrace:
       at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)
       at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization()
       at System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c)
       at System.Data.Entity.Internal.RetryAction`1.PerformAction(TInput input)
       at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action`1 action)
       at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase()
       at System.Data.Entity.Internal.InternalContext.Initialize()
       at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
       at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
       at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
       at System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider()
       at System.Linq.Queryable.Single[TSource](IQueryable`1 source, Expression`1 predicate)
       at Attendance.Web.Controllers.ControllerWithCurrentUser.GetCurrentUser() in .....
       at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.InvokeActionMethodFilterAsynchronouslyRecursive(Int32 filterIndex)
       at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.InvokeActionMethodFilterAsynchronouslyRecursive(Int32 filterIndex)
  InnerException: System.Data.Entity.Core.MetadataException
       HResult=-2146232007
       Message=Schema specified is not valid. Errors: 
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.
       Source=EntityFramework
       StackTrace:
            at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Loader.ThrowOnNonWarningErrors()
            at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Loader.LoadItems(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths)
            at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Loader..ctor(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths, Boolean throwOnError, IDbDependencyResolver resolver)
            at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Init(IEnumerable`1 xmlReaders, IEnumerable`1 filePaths, Boolean throwOnError, IDbDependencyResolver resolver, DbProviderManifest& providerManifest, DbProviderFactory& providerFactory, String& providerInvariantName, String& providerManifestToken, Memoizer`2& cachedCTypeFunction)
            at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection..ctor(IEnumerable`1 xmlReaders)
            at System.Data.Entity.Utilities.XDocumentExtensions.GetStorageMappingItemCollection(XDocument model, DbProviderInfo& providerInfo)
            at System.Data.Entity.Migrations.Infrastructure.EdmModelDiffer.Diff(XDocument sourceModel, XDocument targetModel, Lazy`1 modificationCommandTreeGenerator, MigrationSqlGenerator migrationSqlGenerator)
            at System.Data.Entity.Internal.InternalContext.ModelMatches(XDocument model)
            at System.Data.Entity.Internal.ModelCompatibilityChecker.CompatibleWithModel(InternalContext internalContext, ModelHashCalculator modelHashCalculator, Boolean throwIfNoMetadata)
            at System.Data.Entity.Internal.InternalContext.CompatibleWithModel(Boolean throwIfNoMetadata)
            at System.Data.Entity.Database.CompatibleWithModel(Boolean throwIfNoMetadata)
            at System.Data.Entity.CreateDatabaseIfNotExists`1.<>c__DisplayClass1.<InitializeDatabase>b__0()
            at System.Data.Entity.Internal.MigrationsChecker.IsMigrationsConfigured(InternalContext internalContext, Func`1 databaseExists)
            at System.Data.Entity.CreateDatabaseIfNotExists`1.InitializeDatabase(TContext context)
            at System.Data.Entity.Internal.InternalContext.<>c__DisplayClasse`1.<CreateInitializationAction>b__d()
            at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)
       InnerException: 

注意

Schema specified is not valid. Errors: 
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type datetime2 is not qualified with a namespace or alias. Only primitive types can be used without qualification.
(0,0) : error 0040: The Type nvarchar(max) is not qualified with a namespace or alias. Only primitive types can be used without qualification.

我已经无计可施了。无法弄清楚如何处理这个或如何使 EF 与 MySql 提供程序正常工作。一般而言，在 SO 或网络上对此没有任何用处。我在 http://forums.devart.com/viewtopic.php?t=24678 找到的所有内容都是关于与 Oracle DBS 类似的内容

如果有任何想法，我将不胜感激。我开始认为转移到 NHibernate 会更好，如果我知道它会解决这个问题 - 我想知道这个问题是否与 EF 如何映射实体和生成 SQL 语句或 MySql 提供程序/连接器中的一些错误有关.

最佳答案

当您为 SQL Server 创建迁移，然后将引擎更改为 MySQL 并尝试更新数据库时，就会出现问题。我通过以下方式解决了这个问题:

1. 删除所有迁移类
2. 正在删除 __migrationhistory mysql 表(如果存在)
3. 配置 Entity Framework 以使用 MySQL
4. 创建新的初始迁移。

配置文件需要这个:

<connectionStrings>
    <add name="PrimaryDatabase" providerName="MySql.Data.MySqlClient"
        connectionString="server=localhost;port=3306;database=mydatabase;uid=root;password=root"/>
</connectionStrings>
<entityFramework  codeConfigurationType="MySql.Data.Entity.MySqlEFConfiguration, MySql.Data.Entity.EF6">
    <defaultConnectionFactory type="MySql.Data.Entity.MySqlConnectionFactory, MySql.Data.Entity.EF6" />
    <providers>
      <provider invariantName="MySql.Data.MySqlClient" type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6, Version=6.9.8.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d"/>
    </providers>
</entityFramework>
<system.data>
    <DbProviderFactories>
      <remove invariant="MySql.Data.MySqlClient" />
      <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.9.8.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
    </DbProviderFactories>
</system.data>

DbContext 类使用上面定义的名为 PrimaryDatabase 的连接字符串:

public class ApplicationDbContext : DbContext
{
    public ApplicationDbContext() : base("PrimaryDatabase")
    {
    }

}

最后在migrations配置文件中:

internal sealed class Configuration : DbMigrationsConfiguration<MyProject.ApplicationDbContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
        SetSqlGenerator("MySql.Data.MySqlClient", new MySql.Data.Entity.MySqlMigrationSqlGenerator());
    }
}

您可以找到详细信息here .

关于c# - 带有 EntityFramework 6 架构错误 0040 的 MySql 5.6，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22262817/