具有MySQL连接器6.4.3自动生成表的实体框架4导致“列长度”异常

时间：2011-07-06 20:23:40

标签： mysql asp.net-mvc-3 entity-framework-4

我使用Code First方法处理MySQL和.Net EntityFramework 4。 mysql连接器版本是6.4.3。

当我第一次运行项目时，我的初始化程序会尝试“DropCreateDatabaseAlways”。创建数据库以及所有表。然后抛出以下异常。

Column length too big for column 'ModelHash' (max = 21845); use BLOB or TEXT instead
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.



Exception Details: MySql.Data.MySqlClient.MySqlException: Column length too big for column 'ModelHash' (max = 21845); use BLOB or TEXT instead



Source Error:



Line 38:         public virtual List GetAll()
Line 39:         {
Line 40:             return dbSet.ToList();
Line 41:         }
Line 42: 



Source File: C:\Users\Andrew\Documents\Visual Studio 2010\Projects\SearchCore\OnlineID.DAL\GlobalGatewayRepository.cs    Line: 40



Stack Trace:



[MySqlException (0x80004005): Column length too big for column 'ModelHash' (max = 21845); use BLOB or TEXT instead]
   MySql.Data.MySqlClient.MySqlStream.ReadPacket() +198
   MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int32& insertedId) +73
   MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int32& insertedId) +20
   MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force) +100
   MySql.Data.MySqlClient.MySqlDataReader.NextResult() +836
   MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +1399
   MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() +36
   MySql.Data.MySqlClient.MySqlScript.Execute() +551
   MySql.Data.MySqlClient.MySqlProviderServices.DbCreateDatabase(DbConnection connection, Nullable1 commandTimeout, StoreItemCollection storeItemCollection) +260
   System.Data.Objects.ObjectContext.CreateDatabase() +84
   System.Data.Entity.Internal.DatabaseOperations.CreateIfNotExists(ObjectContext objectContext) +28
   System.Data.Entity.Database.CreateIfNotExists() +53
   System.Data.Entity.DropCreateDatabaseAlways1.InitializeDatabase(TContext context) +233
   System.Data.Entity.<>c__DisplayClass21.<SetInitializerInternal>b__0(DbContext c) +75
   System.Data.Entity.Internal.<>c__DisplayClass5.<PerformDatabaseInitialization>b__3() +19
   System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) +72
   System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() +169
   System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c) +7
   System.Data.Entity.Internal.RetryAction1.PerformAction(TInput input) +118
   System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action1 action) +190
   System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase() +73
   System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) +27
   System.Data.Entity.Internal.Linq.InternalSet1.Initialize() +62
   System.Data.Entity.Internal.Linq.InternalSet1.GetEnumerator() +15
   System.Data.Entity.Infrastructure.DbQuery1.System.Collections.Generic.IEnumerable.GetEnumerator() +40
   System.Collections.Generic.List1..ctor(IEnumerable1 collection) +315
   System.Linq.Enumerable.ToList(IEnumerable1 source) +58
   OnlineID.DAL.GlobalGatewayRepository1.GetAll() in C:\Users\Andrew\Documents\Visual Studio 2010\Projects\SearchCore\OnlineID.DAL\GlobalGatewayRepository.cs:40
   OnlineID.BAL.AccountService.GetAccounts() in C:\Users\Andrew\Documents\Visual Studio 2010\Projects\SearchCore\OnlineID.BAL\AccountService.cs:32
   OnlineID.Website.Controllers.AccountManagement.AccountManagementController.Index() in C:\Users\Andrew\Documents\Visual Studio 2010\Projects\SearchCore\OnlineID.Website\Controllers\AccountManagement\AccountManagementController.cs:29
   lambda_method(Closure , ControllerBase , Object[] ) +62
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +17
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary2 parameters) +208
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary2 parameters) +27
   System.Web.Mvc.<>c_DisplayClass15.b_12() +55
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func1 continuation) +263
   System.Web.Mvc.<>c__DisplayClass17.<InvokeActionMethodWithFilters>b__14() +19
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList1 filters, ActionDescriptor actionDescriptor, IDictionary2 parameters) +191
   System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +343
   System.Web.Mvc.Controller.ExecuteCore() +116
   System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +97
   System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +10
   System.Web.Mvc.<>c__DisplayClassb.<BeginProcessRequest>b__5() +37
   System.Web.Mvc.Async.<>c__DisplayClass1.<MakeVoidDelegate>b__0() +21
   System.Web.Mvc.Async.<>c__DisplayClass81.b__7(IAsyncResult ) +12
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.<>c_DisplayClasse.b_d() +50
   System.Web.Mvc.SecurityUtil.b_0(Action f) +7
   System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) +22
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +60
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8920029
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +184

我不确定这个“ModelHash”列是什么，因为它在我的模型中不存在。

谢谢， AFrieze

我已经确定了这个ModelHash列的位置，它位于EdmMetadata表中，用于跟踪更改。通过添加以下modelBuilder.Conventions.Remove（）;可以消除我遇到的错误。有没有办法将EdmMetadata与MySQL一起使用？

1 个答案:

答案 0 :(得分：1)

IncludeMetadataConvention只是映射EdmMetadata实体。 

void IConfigurationConvention.Apply(ModelConfiguration modelConfiguration)
{
    modelConfiguration.Entity(typeof(EdmMetadata), false).ToTable("EdmMetadata");
}

AFAI看到框架只是检查其他地方是否映射了这个类，并相应地采取行动。

作为一种解决方法，您可以尝试在映射中映射EdmMetadata实体（而不是使用此约定，因此请删除约定），您可以使用适当的大小或类型（文本）显式映射ModelHash属性。关于“如何映射字段的字段长度或类型”，您可以在此处找到信息：How do I specify that a property should generate a TEXT column rather than an nvarchar(4000)根据答案，这应该将列的类型更改为文本：

modelBuilder.Entity<EdmMetadata>()
.Property(e => e.ModelHash)
.HasColumnType("text");

有人可以尝试这种方法吗？

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