使用EF 7:1.0.0-rc1-final,
我在使用数据库第一种方法正确生成查询时遇到问题 - 使用ef脚手架生成DbContext中列出的一些模型属性 - 因为表包含大量列我只需要一些为webapi工作,因此它们是列映射
我有3个实体,品牌,活动和会话
品牌包含许多事件和事件包含许多会话
我的模特:
[Table("tblBranding")]
public class Brand
{
[Key]
[Column("brandingId")]
public int BrandId { get; set; }
[Column("BrandingActive")]
public bool Active { get; set; }
[JsonIgnore]
[Column("DeadBrand")]
public bool DeadBrand { get; set; }
[Column("BrandingSiteTitle")]
public string Name { get; set; }
//navigation properties
public virtual ICollection<Event> Events { get; set; }
}
[Table("tblEvents")]
public class Event
{
public int EventId { get; set; }
[Column("eventActive")]
public bool Active { get; set; }
[Column("eventName")]
public string Name { get; set; }
public DateTime EventCloseDate {get;set;}
public int PaxAllocationLimit { get; set; }
//navigation properties
[JsonIgnore]
[Column("brandingId")]
public virtual int BrandId { get; set; }
[JsonIgnore]
[ForeignKey("BrandId")]
public virtual Brand Brand { get; set; }
public virtual ICollection<Session> Sessions { get; set; }
}
[Table("tblEventsDates")]
public class Session
{
[Column("EventDateID")]
public int SessionId { get; set; }
[Column("EventDateName")]
public string Name { get; set; }
[Column("EventDate")]
public DateTime SessionDate { get; set; }
[Column("EventDateTime")]
public DateTime SessionTime { get; set; }
[Column("EventDateMinutes")]
public decimal? SessionDurationInMinutes { get; set; }
[Column("EventDateArrival")]
public DateTime? ArrivalTime { get; set; }
[Column("EventCapacity")]
public int SessionCapacity { get; set; }
//navigation properties
[JsonIgnore]
public virtual int EventId { get; set; }
[JsonIgnore]
public virtual Event Event { get; set; }
}
我的DbContext
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Event>()
.HasOne(e => e.Brand)
.WithMany(b => b.Events).HasForeignKey(e=>e.BrandId);
modelBuilder.Entity<Event>()
.HasMany(s => s.Sessions)
.WithOne(e => e.Event).HasForeignKey(s => s.EventId);
modelBuilder.Entity<Event>(entity=> {
entity.Property(e => e.EventId).HasColumnName("EventID");
entity.HasKey(e => new{ e.EventId, e.EventCloseDate});
entity.HasIndex(e => e.EventId).HasName("For Full Text Indexing").IsUnique();
entity.Property(e => e.Active).HasDefaultValue(false);
entity.Property(e => e.EventCloseDate)
.HasColumnType("datetime")
.HasDefaultValueSql("'1/1/2038'");
entity.Property(e => e.Name).HasMaxLength(1024);
entity.Property(e => e.PaxAllocationLimit).HasDefaultValue(10000);
});
modelBuilder.Entity<Brand>(entity => {
entity.HasKey(e => e.BrandId);
entity.Property(e => e.Active).HasDefaultValue(false);
entity.Property(e => e.Name)
.IsRequired()
.HasMaxLength(150)
.HasColumnType("varchar");
});
modelBuilder.Entity<Session>(entity => {
entity.HasKey(e => e.SessionId);
entity.Property(e=>e.Name)
.HasMaxLength(250)
.HasColumnType("varchar")
.HasDefaultValue("");
entity.Property(e => e.SessionDurationInMinutes)
.HasColumnType("numeric")
.HasDefaultValue(0m);
});
}
public virtual DbSet<Brand> Brands { get; set; }
public virtual DbSet<Event> Events { get; set; }
public virtual DbSet<Session> Sessions { get; set; }
}
我使用该项目作为webapi,当我调用Brands时,它会生成以下SQL:
SELECT [e].[brandingId], [e].[BrandingActive], [e].[DeadBrand], [e].[BrandingSiteTitle]
FROM [tblBranding] AS [e]
WHERE [e].[BrandingActive] = 1
ORDER BY [e].[BrandingSiteTitle], [e].[brandingId]
Microsoft.Data.Entity.Storage.Internal.RelationalCommandBuilderFactory: Information: Executed DbCommand (75ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT [t].[EventId], [t].[EventCloseDate], [t].[eventActive], [t].[brandingId], [t].[EventId1], [t].[eventName], [t].[PaxAllocationLimit]
FROM [tblEvents] AS [t]
INNER JOIN (
SELECT DISTINCT [e].[BrandingSiteTitle], [e].[brandingId]
FROM [tblBranding] AS [e]
WHERE [e].[BrandingActive] = 1
) AS [e] ON [t].[brandingId] = [e].[brandingId]
ORDER BY [e].[BrandingSiteTitle], [e].[brandingId]
其中[t]。[EventId1]列名无效 请注意,如果我在DbContext中注释掉以下代码 - 此错误消失并且查询生成正确:
modelBuilder.Entity<Event>()
.HasMany(s => s.Sessions)
.WithOne(e => e.Event).HasForeignKey(s => s.EventId);
我尝试添加[ForeignKey],[InverseProperty]属性,同时“摆弄”&#39; - 它似乎没什么区别
我还尝试明确添加列名here
我不知道还有什么可以尝试 - 只有当我在FluidUI中定义与Sessions的关系时才开始发生 - 建议?
答案 0 :(得分:4)
只是为了好玩。尝试制作这个数据库。我删除了很多“杂乱”的EF就像ASP.NET MVC一样,基于约定优于配置的概念。
您最多完成了2次配置(属性和/或FluentApi),而实际上您可以完成0次。
以下是一些关于约定的基本规则(约定对触发器不区分大小写。)
public Brand Brand { get; set; }
类型的属性,如果只有一个“链接”,则名称不重要。public ICollection<Event> Events { get; set; }
是可行的方法。有人可能会问IEnumerable
或IList
(以这种方式来考虑,IEnumerable
无法.Add()
,因此它或多或少是只读的。IList
好吧,它会做得越来越多,如果它不适合做那些不能翻译的东西,那将是一个不错的选择。所以在中间我们有ICollection
。使用虚拟关键字时?好吧在EF7中你不使用它,因为它用于启用延迟加载,而EF7没有(还),我们不知道它们是否要添加它。 Github EF7 feature request lacking lazyload
为什么要删除[JsonIgnore]
属性?切勿将实体模型发送给客户端。创建一个合适的DTO(在ASP.NET MVC中通常称为模型)
记得做迁移,并且(为了好玩)首先尝试在FluentAPI中没有任何“硬编码”要求,并查看将看到PK / FK完成的迁移代码,为您添加索引和其他几个bob和别针
public class Brand
{
public int Id { get; set; }
public bool Active { get; set; }
public bool DeadBrand { get; set; }
public string Name { get; set; }
//navigation properties
public ICollection<Event> Events { get; set; }
}
public class Event
{
public int Id { get; set; }
public bool Active { get; set; }
public string Name { get; set; }
public DateTime EventCloseDate {get;set;}
public int PaxAllocationLimit { get; set; }
//navigation properties
public Brand Brand { get; set; }
public ICollection<Session> Sessions { get; set; }
}
public class Session
{
public int Id { get; set; }
public string Name { get; set; }
//Datetime contains date and time
public DateTime Time { get; set; }
//TimeSpan is for duration, allowing access to seconds, minutes, hours etc.
public TimeSpan Duration { get; set; }
public DateTime? ArrivalTime { get; set; }
public int SessionCapacity { get; set; }
//navigation properties
public Event Event { get; set; }
}
上下文类
class DbContex{
public virtual DbSet<Brand> Brands { get; set; }
public virtual DbSet<Event> Events { get; set; }
public virtual DbSet<Session> Sessions { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
//Personally I would not have many requirements in the database unless I
//was completely sure it had to be that way.
//They will ALWAYS bite you in the ass in the long run.
modelBuilder.Entity<Event>(entity=> {
entity.Property(e => e.Active).HasDefaultValue(false);
entity.Property(e => e.EventCloseDate)
.HasColumnType("datetime")
.HasDefaultValueSql("'1/1/2038'");
entity.Property(e => e.Name).HasMaxLength(1024);
entity.Property(e => e.PaxAllocationLimit).HasDefaultValue(10000);
});
modelBuilder.Entity<Brand>(entity => {
entity.Property(e => e.Active).HasDefaultValue(false);
entity.Property(e => e.Name)
.IsRequired()
.HasMaxLength(150)
.HasColumnType("varchar");
});
modelBuilder.Entity<Session>(entity => {
entity.Property(e=>e.Name)
.HasMaxLength(250)
.HasColumnType("varchar")
.HasDefaultValue("");
entity.Property(e => e.SessionDurationInMinutes)
.HasColumnType("numeric")
.HasDefaultValue(0m);
});
}
}
}
答案 1 :(得分:1)
回答我自己的问题 - 好像它可能是EF 7 1.0.0-RC1中的一个错误
在DbContext中的Event的实体属性
中 modelBuilder.Entity<Event>(entity=> {
entity.Property(e => e.EventId).HasColumnName("EventID");
entity.HasKey(e => new{ e.EventId, e.EventCloseDate});
entity.HasIndex(e => e.EventId).HasName("For Full Text Indexing").IsUnique();
entity.Property(e => e.Active).HasDefaultValue(false);
entity.Property(e => e.EventCloseDate)
.HasColumnType("datetime")
.HasDefaultValueSql("'1/1/2038'");
entity.Property(e => e.Name).HasMaxLength(1024);
entity.Property(e => e.PaxAllocationLimit).HasDefaultValue(10000);
});
请注意,它有2个键 - 这是从脚手架生成的,该表有一个复合主键
但是对于我对API的要求,我只需要一个主要标识符 - 删除复合键修复了无效列生成错误
更新代码:
modelBuilder.Entity<Event>(entity=> {
entity.Property(e => e.EventId).HasColumnName("EventID");
entity.HasKey(e => e.EventId);
entity.HasIndex(e => e.EventId).HasName("For Full Text Indexing").IsUnique();
entity.Property(e => e.Active).HasDefaultValue(false);
entity.Property(e => e.EventCloseDate)
.HasColumnType("datetime")
.HasDefaultValueSql("'1/1/2038'");
entity.Property(e => e.Name).HasMaxLength(1024);
entity.Property(e => e.PaxAllocationLimit).HasDefaultValue(10000);
});