MySQL - 实体：表'TableDetails'中的列'IsPrimaryKey'的值为DBNull [英] MySQL - Entity : The value for column 'IsPrimaryKey' in table 'TableDetails' is DBNull

问题描述

我使用 Visual Studio 2013 与实体框架5 和M ySQL Server 5.7.9 。

当尝试从数据库（或'从数据库更新模型'）创建模型时，会出现以下消息：

< blockquote>

'System.Data.StrongTypingException：表'TableDetails'中的列
'IsPrimaryKey'的值为DBNull。 ---> System.InvalidCastException：指定的转换无效

我知道这个问题以前已经被问过了，但是我还没有找不到任何解决方案。
此外，我没有选择降级到MySQL 5.6。

即使是一个简单的表格也会出现问题。

样本表

  CREATE TABLE new_table 
（
 id int ）NOT NULL AUTO_INCREMENT，
 name varchar（45）NOT NULL，
 PRIMARY KEY（id）
）
 ENGINE = InnoDB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8; 
  

如果表仅由主键组成，那么该模型正在被创建。 p>

编辑：
如果我同时创建两个字段PRIMARY键，那么模型正在被创建而没有任何错误。

有没有人对此有任何想法？

请问。

完全错误堆栈：

由于以下异常，无法生成模型：
'System.Data.StrongTypingException：值对于列
'TableDetails'中的'IsPrimaryKey'是DBNull。 --->
System.InvalidCastException：指定的转换无效。 at
Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.SchemaDiscovery.TableDetailsRow.get_IsPrimaryKey（）
---内部异常堆栈跟踪结束---在Microsoft.Data.Entity.Design.VersioningFacade .ReverseEngineerDb.SchemaDiscovery.TableDetailsRow.get_IsPrimaryKey（）

Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateProperties（IList 1
列，IList 1个错误，列表 1& keyColumns，List 1& excludedColumns，
列表 1& invalidKeyTypeColumns） b
$ b Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateEntityType（IList 1
columns，Boolean& needsDefiningQuery）
Microsoft.Data.Entity.Design .VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateEntitySets（IEnumerable 1
tableDetailsRows，EntityRegister entityRegister，IList 1
entitySetsForReadOnlyEntityTypes，DbObjectT ype objectType）
Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateEntitySets（IEnumerable 1
tableDetailsRowsForTables，IEnumerable 1 tableDetailsRowsForViews，
EntityRegister entityRegister）在
Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.Build（StoreSchemaDetails
storeSchemaDetails）
Microsoft.Data.Entity.Design.VisualStudio.ModelWizard .Engine.ModelGenerator.CreateStoreModel（）

Microsoft.Data.Entity.Design.VisualStudio.ModelWizard.Engine.ModelGenerator.GenerateModel（List 1
errors）at
Microsoft.Data.Entity.Design.VisualStudio.ModelWizard.Engine.ModelBuilderEngine.GenerateModels（String
storeModelNamespace，List 1个错误）
Microsoft.Data.Entity .Design.VisualStudio.ModelWizard.Engine.ModelBuilderEngine.GenerateModel（EdmxHelper
edmxHelper）'。从数据库加载元数据需要
00：00：00.5856317。

解决方案

实体框架（版本6.1.3）和MySQL服务器（> = 5.7.6）

解决问题的一种方法是，

  1。打开服务（services.msc）并重启MySQL57服务。 
 2.在MySQL中执行以下命令。 
使用<< database name>> ;; 
设置全局optimizer_switch ='derived_merge = OFF'; 
 3.更新.edmx。 
  

这是一个迟到的回复。但希望能帮助某人。

谢谢。

I am using Visual Studio 2013 with Entity Framework 5 and MySQL Server 5.7.9.

When trying to create a Model from the database (or 'Update Model From Database') the following message appears:

'System.Data.StrongTypingException: The value for column 'IsPrimaryKey' in table 'TableDetails' is DBNull . ---> System.InvalidCastException: Specified cast is not valid.

I know that this question has been asked before, but i haven't find any solution. Also i don't have the option of downgrading to MySQL 5.6.

The problem occurs even for a simple table.

The sample table

CREATE TABLE new_table
(
  id int(11) NOT NULL AUTO_INCREMENT,
  name varchar(45) NOT NULL,
  PRIMARY KEY (id)
) 
ENGINE = InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

If the table consists only from the Primary Key then the model is being created as it should.

EDIT: If i make both the fields PRIMARY Keys the model is being created without any errors.

Does anyone have any idea about this?

Kind Regards.

The full error stack:

Unable to generate the model because of the following exception: 'System.Data.StrongTypingException: The value for column 'IsPrimaryKey' in table 'TableDetails' is DBNull. ---> System.InvalidCastException: Specified cast is not valid. at Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.SchemaDiscovery.TableDetailsRow.get_IsPrimaryKey() --- End of inner exception stack trace --- at Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.SchemaDiscovery.TableDetailsRow.get_IsPrimaryKey() at Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateProperties(IList1 columns, IList1 errors, List1& keyColumns, List1& excludedColumns, List1& invalidKeyTypeColumns) at Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateEntityType(IList1 columns, Boolean& needsDefiningQuery) at Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateEntitySets(IEnumerable1 tableDetailsRows, EntityRegister entityRegister, IList1 entitySetsForReadOnlyEntityTypes, DbObjectType objectType) at Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.CreateEntitySets(IEnumerable1 tableDetailsRowsForTables, IEnumerable1 tableDetailsRowsForViews, EntityRegister entityRegister) at Microsoft.Data.Entity.Design.VersioningFacade.ReverseEngineerDb.StoreModelBuilder.Build(StoreSchemaDetails storeSchemaDetails) at Microsoft.Data.Entity.Design.VisualStudio.ModelWizard.Engine.ModelGenerator.CreateStoreModel() at Microsoft.Data.Entity.Design.VisualStudio.ModelWizard.Engine.ModelGenerator.GenerateModel(List1 errors) at Microsoft.Data.Entity.Design.VisualStudio.ModelWizard.Engine.ModelBuilderEngine.GenerateModels(String storeModelNamespace, List1 errors) at Microsoft.Data.Entity.Design.VisualStudio.ModelWizard.Engine.ModelBuilderEngine.GenerateModel(EdmxHelper edmxHelper)'. Loading metadata from the database took 00:00:00.5856317.

解决方案

Entity Framework (version 6.1.3) and MySQL Server (>= 5.7.6)

One way to resolve the issue is,

1. Open Services (services.msc) and restart MySQL57 service.
2. Execute the following commands in MySQL.
   use <<database name>>;
   set global optimizer_switch='derived_merge=OFF';
3. Update the .edmx.

It's a late reply. But hope it will help somebody.

Thanks.

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