[英]Problems using MySQL with Entity Framework
我在將實體框架與MySQL Connector / NET 6.4.4一起使用插入行時遇到問題。 當我嘗試添加1行后保存更改時,出現了System.NullReferenceException並帶有以下堆棧跟蹤:
at MySql.Data.Entity.SqlGenerator.GenerateReturningSql(DbModificationCommandTree tree, DbExpression returning)
at MySql.Data.Entity.UpdateGenerator.GenerateSQL(DbCommandTree tree)
at MySql.Data.MySqlClient.MySqlProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree)
at System.Data.Common.DbProviderServices.CreateCommandDefinition(DbCommandTree commandTree)
at System.Data.Common.DbProviderServices.CreateCommand(DbCommandTree commandTree)
at System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.CreateCommand(UpdateTranslator translator, Dictionary`2 identifierValues)
at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues)
at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)
at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at UserData.Repository.DBRepositoryDataContext.SaveChanges() in C:\SoftwareProjects\Java\Degoo\Server\UserData\Repository\DBRepositoryDataContext.cs:line 42
at UserData.Repository.Repository.<SaveChanges>b__1() in C:\SoftwareProjects\Java\Degoo\Server\UserData\Repository\Repository.cs:line 137
at Microsoft.AppFabricCAT.Samples.Azure.TransientFaultHandling.RetryPolicy`1.ExecuteAction(Action action) in C:\SoftwareProjects\Java\Degoo\Server\Libraries\TransientFaultHandlingFramework\RetryPolicy.cs:line 352
我將EF 4.1和“代碼優先”一起使用。 換句話說:我使用DbSet和DbContext。
這就是我要添加的實體在EF的變更跟蹤器中的樣子:
System.Data.Entity.Infrastructure.DbEntityEntry<Utilities.IStandardEntity>
_internalEntityEntry System.Data.Entity.Internal.InternalEntityEntry
CurrentValues System.Data.Entity.Infrastructure.DbPropertyValues
Entity UserData.PerformanceCounterEntities.PerformanceCounterEntity
CallingClassName "com.degoo.tests.integration.PerformanceCounterUploaderTest" string
Category {System.Data.Entity.DynamicProxies.TextEntity_27BF3732ED645CE792F48B4AA75BFD05C10C0AE9C5B35779176C02A53A587F1A} UserData.PerformanceCounterEntities.TextEntity {System.Data.Entity.DynamicProxies.TextEntity_27BF3732ED645CE792F48B4AA75BFD05C10C0AE9C5B35779176C02A53A587F1A}
CategoryTextID 1 long
CreationTime {2011-11-09 09:32:12} System.DateTime
Description {System.Data.Entity.DynamicProxies.TextEntity_27BF3732ED645CE792F48B4AA75BFD05C10C0AE9C5B35779176C02A53A587F1A} UserData.PerformanceCounterEntities.TextEntity {System.Data.Entity.DynamicProxies.TextEntity_27BF3732ED645CE792F48B4AA75BFD05C10C0AE9C5B35779176C02A53A587F1A}
DescriptionTextID 3 long
ID 0 long
ModificationTime {2011-11-09 09:32:12} System.DateTime
Name {System.Data.Entity.DynamicProxies.TextEntity_27BF3732ED645CE792F48B4AA75BFD05C10C0AE9C5B35779176C02A53A587F1A} UserData.PerformanceCounterEntities.TextEntity {System.Data.Entity.DynamicProxies.TextEntity_27BF3732ED645CE792F48B4AA75BFD05C10C0AE9C5B35779176C02A53A587F1A}
NameTextID 2 long
NodeID 16485 long
NumberOfSamples 1 long
RowVersion 0 long
Value 1.0 double
關於什么原因的任何想法? 它看起來像是MySQL的EF驅動程序中的錯誤(至少它們應該先更新然后提供更好的錯誤消息)。
使用相同的連接器驅動程序,我遇到了類似的問題。 就我而言,其中一個對象使用屬性而不是屬性。
public class User : ProjectBasicEntity
{
public string SomeColumn;
}
代替
public class User : ProjectBasicEntity
{
public string SomeColumn { get; set;}
}
我猜確實有人需要改善這些驅動程序中的錯誤處理...
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