c# - Entity Framework - 无法更新 EntitySet 二进制数据

Question

Entity Framework 抛出错误:

Test 'WorkerProcessService.Test.WorkerProcessMonitorTests.Test' failed: System.Data.UpdateException : Unable to update the EntitySet 'Processor' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.
 at System.Data.SqlClient.SqlGen.DmlSqlGenerator.ExpressionTranslator.Visit(DbScanExpression expression)
 at System.Data.Common.CommandTrees.DbScanExpression.Accept(DbExpressionVisitor visitor)
 at System.Data.SqlClient.SqlGen.DmlSqlGenerator.GenerateInsertSql(DbInsertCommandTree tree, SqlVersion sqlVersion, List`1& parameters)
 at System.Data.SqlClient.SqlGen.SqlGenerator.GenerateSql(DbCommandTree tree, SqlVersion sqlVersion, List`1& parameters, CommandType& commandType, HashSet`1& paramsToForceNonUnicode)
 at System.Data.SqlClient.SqlProviderServices.CreateCommand(DbProviderManifest providerManifest, DbCommandTree commandTree)
 at System.Data.SqlClient.SqlProviderServices.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.Objects.ObjectContext.SaveChanges()
 WorkerProcessMonitor.cs(79,0): at Star.Portal.Services.WorkerProcessMonitor.AddComponent(Byte[] component)
 WorkerProcessMonitorTests.cs(55,0): at WorkerProcessService.Test.WorkerProcessMonitorTests.Test()

我有一个类似的表格和自动生成的 edmx 模型

CREATE TABLE [dbo].[Processor](
  [ProcessorID] [int] IDENTITY(1,1) NOT NULL,
  [ProcessorDLL] [varbinary](max) NULL,
)

以下更新失败

public void AddComponent(byte[] component)
        {
            Processor p = new Processor()
                              {
                                  ProcessorDLL = component,
                              };
             using (var cn = GetWorkerProcessEntities())
             {

                 cn.AddToProcessors(p);
                 cn.SaveChanges();
             }

        }

问题是:我是否必须做任何特定的事情才能在 sql server 中实现二进制存储？

Answer 1

简单的回答...不，我将图像存储在具有相同数据类型 (varbinary(max)) 的表中。

我不太了解您的代码，我使用本地数据库进行了简单测试。 这是我的 POCO 和 DBcontext。 (我不使用自动生成的 edmx)

using System.Data.Entity.ModelConfiguration;
public class Processor
{
    public int ProcessorId { get; set; }
    public byte[] ProcessorDLL { get; set; }
}
public class ProcessorConfiguration : EntityTypeConfiguration<Processor>
{
    public ProcessorConfiguration()
    {
        HasKey(i => i.ProcessorId);

        ToTable("Processor", "dbo");
    }
}
//DbContext
public class myContext : DbContext
{
    public DbSet<Processor> Processors { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Configurations.Add(new ProcessorConfiguration());
        base.OnModelCreating(modelBuilder);
    }
}

然后当我添加一个新的处理器时，我使用这个

public void test()
    {
        myContext context = new myContext();

        Processor p = new Processor
        {
            ProcessorDLL = getSomeRandomByteArray()
        };

        context.Processors.Add(p);
        context.SaveChanges();
    }

在我的 table 上:

ProcessorID: 1
ProcessorDLL: 0xFFD8FFE000104A46494600010200...

希望这对您有所帮助。