相关疑难解决方法(0)

不久,我想在我的表上创建复合键,保留主键,以提高sql server搜索性能.每当我搜索没有主键的实体(即一串GUID)时,性能问题就会发生在200k数据表上.假设我有3个班级

public class Device{

    public int ID { get; set; } 
    public string UDID { get; set; }
    public string ApplicationKey { get; set; }
    public string PlatformKey { get; set; }

    public ICollection<NotificationMessageDevice> DeviceMessages { get; set; } 
}

public class NotificationMessageDevice { 

    [Column(Order = 0), Key, ForeignKey("NotificationMessage")]
    public int NotificationMessage_ID { get; set; }

    [Column(Order = 1), Key, ForeignKey("Device")]
    public int Device_ID { get; set; }

    public virtual Device Device { get; set; }
    public virtual NotificationMessage …

我正在使用Entity Framework Codefirst来创建我的数据库.当我通过ODBC连接到它时,具有模式名称dbo.pk_Jobs的默认主键似乎扰乱了访问2007.如果我手动编辑名称并删除模式名称并将此主键重命名为pk_jobs,则Access现在可以读取该表.

是否可以使用Fluent Api,数据属性或任何其他方法指定主键名称不包括架构的名称.

public class ReportsContext : DbContext
{
    public DbSet<Job> Jobs { get; set; }
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Job>().ToTable("Jobs");
        modelBuilder.Entity<Job>().HasKey(j => j.uuid);

        base.OnModelCreating(modelBuilder);
    }
}
public class Job
{
    public Guid uuid{ get; set; }
    public int active{ get; set; }
}

我有一个表(Id,name,itemst,otherproperties),Id是主键,我想要一个唯一的复合键(name,itemst).如何使用代码首先通过流畅的API(首选)或注释添​​加此代码？

我在 SQLite 的 Ef 核心模型中有这个类定义。

public class Ejercicios : BaseModel
{
    private int _TipoEjercicio;
    [Key]
    public int TipoEjercicio
    {
        get { return _TipoEjercicio; }
        set { SetProperty(ref _TipoEjercicio, value); }
    }

    private string _DescripcionEjercicio;
    public string DescripcionEjercicio
    {
        get { return _DescripcionEjercicio; }
        set { SetProperty(ref _DescripcionEjercicio, value); }
    }

    private string _HexForeColor;
    public string HexForeColor
    {
        get { return _HexForeColor; }
        set { SetProperty(ref _HexForeColor, value); }
    }

    private string _HexBackGroundColor;
    public string HexBackGroundColor
    {
        get { return _HexBackGroundColor; …

System.InvalidOperationException: The instance of entity type 'ProjectAssignment' cannot be tracked because another instance with the same key value for {'ProjectID'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap`1.Add(TKey key, InternalEntityEntry entry)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.St

我制作了一个带有Worker（ID和其他列）和Project（ID和其他列）Entity和ProjectAssignment（许多ID分配给许多Workers）的项目。但是，当我尝试获取ProjectAssignment数据时，会出现Application Insights中的错误。奇怪的是，该ID并未更早出现。

这是https://github.com/Streamc/ContosoObserve1/tree/master/Proj_s

 context.Database.EnsureCreated();

  var ProjectAssignments = new ProjectAssignment[]
             {
                    new ProjectAssignment
                    {
                        ProjectID = Projects.Single( i => i.ID == 1).ID,
                        WorkerID …