c# - EF 查询 Oracle 抛出 "ORA-12704: character set mismatch"

Question

我试图在 Oracle 的 EF 中组合几列，然后像这样对这些列执行 .Contains():

public IEnumerable<User> SearchUsers(string search)
{
    search = search.ToLower();

    return _securityUow.Users
            .Where(u => (u.FirstName.ToLower() + " " + u.LastName.ToLower() + " (" + u.NetId.ToLower() + ")").Contains(search))
            .OrderBy(u => u.LastName)
            .ThenBy(u => u.FirstName)
            .AsEnumerable();
}

但是，我遇到了这个异常:

{
  "Message": "An error has occurred.",
  "ExceptionMessage": "An error occurred while executing the command definition. See the inner exception for details.",
  "ExceptionType": "System.Data.Entity.Core.EntityCommandExecutionException",
  "StackTrace": "   at SoftwareRegistration.WebUI.Controllers.Api.V1.UserContactController.Lookup(String search) in C:\LocalRepository\OnlineSupport\SoftwareRegistration\trunk\release\SoftwareRegistration\SoftwareRegistration.WebUI\Controllers\Api\V1\UserContactController.cs:line 40\r\n   at lambda_method(Closure , Object , Object[] )\r\n   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)\r\n   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)\r\n   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at System.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()",
  "InnerException": {
    "Message": "An error has occurred.",
    "ExceptionMessage": "ORA-12704: character set mismatch",
    "ExceptionType": "Oracle.ManagedDataAccess.Client.OracleException",
    "StackTrace": "   at OracleInternal.ServiceObjects.OracleCommandImpl.VerifyExecution(OracleConnectionImpl connectionImpl, Int32& cursorId, Boolean bThrowArrayBindRelatedErrors, OracleException& exceptionForArrayBindDML, Boolean& hasMoreRowsInDB, Boolean bFirstIterationDone)\r\n   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)\r\n   at Oracle.ManagedDataAccess.Client.OracleCommand.ExecuteReader(Boolean requery, Boolean fillRequest, CommandBehavior behavior)\r\n   at Oracle.ManagedDataAccess.Client.OracleCommand.ExecuteDbDataReader(CommandBehavior behavior)\r\n   at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)\r\n   at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<Reader>b__c(DbCommand t, DbCommandInterceptionContext`1 c)\r\n   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)\r\n   at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.Reader(DbCommand command, DbCommandInterceptionContext interceptionContext)\r\n   at System.Data.Entity.Internal.InterceptableDbCommand.ExecuteDbDataReader(CommandBehavior behavior)\r\n   at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)\r\n   at System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)"
  }
}

我正在查询的列在 Oracle 中都是 VARCHAR2(128) 类型。

我也在另一个项目中使用了完全相同的代码并且它有效。唯一的区别是，对于有效的项目，我使用 Oracle.DataAccess，对于无效的项目，我使用 Oracle.ManagedDataAccess(我我无法为此项目使用 Oracle.DataAccess)。所以我相信托管驱动程序中存在错误/问题。

我愿意接受解决方案或变通办法。

Answer 1

我最终让这个 ( ODP.Net Managed Driver - ORA-12704: character set mismatch in generated code ) 的作者更新了这个问题，他发布了一个使用拦截器的解决方法，我将在这里详细介绍一下......

首先，我修饰了 DBContext 以加载配置。你可以跳过这个，如果你有一个，只需添加到你的配置中:

[DbConfigurationType(typeof(MyDbConfiguration))]
public partial class MyContext : DbContext

创建配置类:

public class MyDbConfiguration : DbConfiguration
{
    public MyDbConfiguration()
    {
        this.AddInterceptor(new NVarcharInterceptor()); //add this line to existing config.
    }
}

接下来，创建拦截器:

public class NVarcharInterceptor : IDbCommandInterceptor
{
    public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        if (command != null && !string.IsNullOrWhiteSpace(command.CommandText))
            command.CommandText = command.CommandText.Replace("N''", "''");
    }

    public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        if (command != null && !string.IsNullOrWhiteSpace(command.CommandText))
            command.CommandText = command.CommandText.Replace("N''", "''");
    }

    public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        if (command != null && !string.IsNullOrWhiteSpace(command.CommandText))
            command.CommandText = command.CommandText.Replace("N''", "''");
    }

    public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        if (command != null && !string.IsNullOrWhiteSpace(command.CommandText))
            command.CommandText = command.CommandText.Replace("N''", "''");
    }

    public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        if (command != null && !string.IsNullOrWhiteSpace(command.CommandText))
            command.CommandText = command.CommandText.Replace("N''", "''");
    }

    public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        if (command != null && !string.IsNullOrWhiteSpace(command.CommandText))
            command.CommandText = command.CommandText.Replace("N''", "''");
    }
}