c# - 使用 EF 6 和 Oracle.ManagedDataAccess 时表不存在

Question

我正在创建一个 MVC 应用程序，使用 EF 6.0.0.0 和 ODP.Net Oracle.ManagedDataAccess 版本 4.121.2.0 进行数据访问.

在名为 EmployeeController 的 Controller 中，我有以下代码片段:

public ActionResult Details(int id) {
    try {
        EmployeeContext employeeContext = new EmployeeContext();
        Employee employee = employeeContext.Employees.Single(x => x.Id == id); //Here the exception occurs!
        return View(employee);
    } catch (Exception e) {
        return View(e);
    }
}

当我加载 Employee/Details.cshtml 页面时，出现以下异常:

"An error occurred while executing the command definition. See the inner exception for details."

在内部异常中，它说:

ORA-00942: table or view does not exist

这让我感到困惑，因为在我的 Oracle 数据库中，该表肯定存在(我使用 Toad for Oracle 检查过):

数据库本身的 connectionString 与我在其他项目中使用的连接字符串相同，我可以在其中轻松地从数据库中查询数据。

下面是我的 Employee 类是如何在 Models/Employee.cs 中声明的:

using System.ComponentModel.DataAnnotations.Schema;
.
.
.
[Table("TBLEMPLOYEE")] //the same table name
public class Employee {
    public int Id { get; set; }
    public string Name { get; set; }
    public string Gender { get; set; }
    public DateTime DateOfBirth { get; set; }
    public int EmployeeType { get; set; }
    public double? AnnualSalary { get; set; }
    public double? HourlyPay { get; set; }
    public double? HoursWorked { get; set; }
    public string City { get; set; }
}

而我的 Models/EmployeeContext.cs 只是由一个元素组成:

using System.Data.Entity;
.
.
.
public class EmployeeContext : DbContext {
    public DbSet<Employee> Employees { get; set; }
}

并且在 Global.asax.cs 文件中，我已经为 EmployeeContext 模型初始化了数据库:

protected void Application_Start() { //executed at the very beginning               
    Database.SetInitializer<MvcWebApplication1.Models.EmployeeContext>(null); //null -> no initialization strategy
    AreaRegistration.RegisterAllAreas();
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);
}

如果表不存在，我仍然会收到什么错误？这里可能出什么问题？有什么建议如何调试这种情况吗？

编辑:

当我评估 employeeContext.Employees 时，我得到以下值:

{SELECT 
"Extent1"."Id" AS "Id", 
"Extent1"."Name" AS "Name", 
"Extent1"."Gender" AS "Gender", 
"Extent1"."DateOfBirth" AS "DateOfBirth", 
"Extent1"."EmployeeType" AS "EmployeeType", 
"Extent1"."AnnualSalary" AS "AnnualSalary", 
"Extent1"."HourlyPay" AS "HourlyPay", 
"Extent1"."HoursWorked" AS "HoursWorked", 
"Extent1"."City" AS "City"
FROM "dbo"."TBLEMPLOYEE" "Extent1"}

编辑 2:

使用:

employeeContext.Database.Log = s => System.Diagnostics.Debug.WriteLine(s);

我在调试输出窗口中得到以下信息:

SELECT 
"Extent1"."Id" AS "Id", 
"Extent1"."Name" AS "Name", 
"Extent1"."Gender" AS "Gender", 
"Extent1"."DateOfBirth" AS "DateOfBirth", 
"Extent1"."EmployeeType" AS "EmployeeType", 
"Extent1"."AnnualSalary" AS "AnnualSalary", 
"Extent1"."HourlyPay" AS "HourlyPay", 
"Extent1"."HoursWorked" AS "HoursWorked", 
"Extent1"."City" AS "City"
FROM "dbo"."TBLEMPLOYEE" "Extent1"
WHERE ("Extent1"."Id" = :p__linq__0) AND (ROWNUM <= (2) )

编辑 3:

这是我的连接字符串的样子，以备不时之需

  <connectionStrings>
    <add name="DefaultConnection" connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\aspnet-MvcWebApplication1-20160212010850.mdf;Initial Catalog=aspnet-MvcWebApplication1-20160212010850;Integrated Security=True"
      providerName="System.Data.SqlClient" />
    <add name="EmployeeContext" connectionString="Data source=thisisfakedatasource;user id=thisisfakename;password=thisisfakepassword;persist security info=True"
      providerName="Oracle.ManagedDataAccess.Client"/>
  </connectionStrings>  

entityFramework 的设置如下:

  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="mssqllocaldb" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
      <provider invariantName="Oracle.ManagedDataAccess.Client" type="Oracle.ManagedDataAccess.EntityFramework.EFOracleProviderServices, Oracle.ManagedDataAccess.EntityFramework, Version=6.121.2.0, Culture=neutral, PublicKeyToken=89b483f429c47342" />
    </providers>
  </entityFramework>

任何问题可能出在哪里的线索？

附加信息:

异常堆栈跟踪:

e.StackTrace

   at System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)
   at System.Data.Entity.Core.Objects.Internal.ObjectQueryExecutionPlan.Execute[TResultType](ObjectContext context, ObjectParameterCollection parameterValues)
   at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClass7.<GetResults>b__6()
   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
   at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClass7.<GetResults>b__5()
   at System.Data.Entity.Infrastructure.DefaultExecutionStrategy.Execute[TResult](Func`1 operation)
   at System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
   at System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__0()
   at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()
   at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
   at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.<GetElementFunction>b__3[TResult](IEnumerable`1 sequence)
   at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot)
   at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute[TResult](Expression expression)
   at System.Data.Entity.Internal.Linq.DbQueryProvider.Execute[TResult](Expression expression)
   at System.Linq.Queryable.Single[TSource](IQueryable`1 source, Expression`1 predicate)
   at MvcWebApplication1.Controllers.EmployeeController.Details(Int32 id) in c:\myapp\Controllers\EmployeeController.cs:line 25

内部异常堆栈跟踪:

(e.InnerException).StackTrace

   at OracleInternal.ServiceObjects.OracleCommandImpl.VerifyExecution(OracleConnectionImpl connectionImpl, Int32& cursorId, Boolean bThrowArrayBindRelatedErrors, OracleException& exceptionForArrayBindDML, Boolean& hasMoreRowsInDB, Boolean bFirstIterationDone)
   at OracleInternal.ServiceObjects.OracleCommandImpl.ExecuteReader(String commandText, OracleParameterCollection paramColl, CommandType commandType, OracleConnectionImpl connectionImpl, OracleDataReaderImpl& rdrImpl, Int32 longFetchSize, Int64 clientInitialLOBFS, OracleDependencyImpl orclDependencyImpl, Int64[] scnForExecution, Int64[]& scnFromExecution, OracleParameterCollection& bindByPositionParamColl, Boolean& bBindParamPresent, Int64& internalInitialLOBFS, OracleException& exceptionForArrayBindDML, Boolean isDescribeOnly, Boolean isFromEF)
   at Oracle.ManagedDataAccess.Client.OracleCommand.ExecuteReader(Boolean requery, Boolean fillRequest, CommandBehavior behavior)
   at Oracle.ManagedDataAccess.Client.OracleCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
   at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<Reader>b__c(DbCommand t, DbCommandInterceptionContext`1 c)
   at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext,TResult](TTarget target, Func`3 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
   at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.Reader(DbCommand command, DbCommandInterceptionContext interceptionContext)
   at System.Data.Entity.Internal.InterceptableDbCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
   at System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)

Answer 1

未找到数据表的问题，如DevilSuichiro所述在评论中，是由于使用了错误的 Schema。默认情况下，EF 6 使用 dbo 作为默认架构，而我的架构不是 dbo。要使模型具有默认架构，需要重写 OnModelCreating 事件:

public class EmployeeContext : DbContext {
    public DbSet<Employee> Employees { get; set; }
    protected override void OnModelCreating(DbModelBuilder modelBuilder) {
        modelBuilder.HasDefaultSchema("myschema");
    }
}

另外，感谢 Ivan Stoev感谢他建议检查 EF 生成的 SQL。