I'm having an issue with EF6 and many-to-many relations. I have a following setup:
我遇到了EF6和多对多关系的问题。我有以下设置:
public class Foo
{
public int Id { get; set; }
public virtual ICollection<Bar> Bars { get; set; }
public virtual ICollection<SubBar> SubBars { get; set; }
public Foo()
{
Bars = new HashSet<Bar>();
SubBars = new HashSet<SubBar>();
}
}
public class Bar
{
public int Id { get; set; }
public virtual ICollection<Foo> Foos { get; set; }
public Bar()
{
Foos = new HashSet<Foo>();
}
}
public class SubBar
{
public int Id { get; set; }
public virtual ICollection<Foo> Foos { get; set; }
public SubBar()
{
Foos = new HashSet<Foo>();
}
}
The relation between Foo
and Bar
works properly, and there is a table called BarFoos
in the DB. However the relation between Foo
and SubBar
is reversed. There is a table in the DB called FooSubBars
which basically holds the correct relations, but eager loading, like SubBar.AsQueryable().Include(sb => sb.Foos)
returns an EntityCommandExecutionException
with a message Invalid object name dbo.SubBarFoos
.
Foo和Bar之间的关系正常工作,DB中有一个名为BarFoos的表。然而,Foo和SubBar之间的关系是相反的。数据库中有一个名为FooSubBars的表,它基本上保持正确的关系,但是像SubBar.AsQueryable()一样急切加载.Include(sb => sb.Foos)返回一个EntityCommandExecutionException,其中包含一个消息Invalid object name dbo.SubBarFoos。
Question is: How do I reverse the relation table name to allow eager loading?
--Edit--
DB creation in the migration is as follows:
问题是:如何反转关系表名称以允许急切加载? --Edit--迁移中的数据库创建如下:
CreateTable(
"dbo.BarFoos",
c => new
{
Bar_Id = c.Int(nullable: false),
Foo_Id = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.Bar_Id, t.Foo_Id })
.ForeignKey("dbo.Bars", t => t.Bar_Id, cascadeDelete: true)
.ForeignKey("dbo.Foos", t => t.Foo_Id, cascadeDelete: true)
.Index(t => t.Bar_Id)
.Index(t => t.Foo_Id);
CreateTable(
"dbo.FooSubBars",
c => new
{
Foo_Id = c.Int(nullable: false),
SubBar_Id = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.Foo_Id, t.SubBar_Id })
.ForeignKey("dbo.Foos", t => t.Foo_Id, cascadeDelete: true)
.ForeignKey("dbo.SubBars", t => t.SubBar_Id, cascadeDelete: true)
.Index(t => t.Foo_Id)
.Index(t => t.SubBar_Id);
Would replacing the table name in the migration be sufficient?
在迁移中替换表名是否足够?
2 个解决方案
#1
You can ensure the table name is generated as "FooBars" if you override the OnModelCreating method on your DbContext as follows:
如果您在DbContext上覆盖OnModelCreating方法,则可以确保将表名生成为“FooBars”,如下所示:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Foo>().HasMany(f => f.Bars).WithMany(b => b.Foos)
.Map(m =>
m.ToTable("FooBars")
// Optionally specify the key column names...
.MapLeftKey("FooId")
.MapRightKey("BarId")
);
modelBuilder.Entity<Foo>().HasMany(f => f.SubBars).WithMany(sb => sb.Foos).Map(m => m.ToTable("FooSubBars"));
}
Which will produce this in the migration:
这将在迁移中产生这种情况:
CreateTable(
"dbo.FooBar",
c => new
{
FooId = c.Int(nullable: false),
BarId = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.FooId, t.BarId })
.ForeignKey("dbo.Foos", t => t.FooId, cascadeDelete: true)
.ForeignKey("dbo.Bars", t => t.BarId, cascadeDelete: true)
.Index(t => t.FooId)
.Index(t => t.BarId);
CreateTable(
"dbo.FooSubBar",
c => new
{
Foo_Id = c.Int(nullable: false),
SubBar_Id = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.Foo_Id, t.SubBar_Id })
.ForeignKey("dbo.Foos", t => t.Foo_Id, cascadeDelete: true)
.ForeignKey("dbo.SubBars", t => t.SubBar_Id, cascadeDelete: true)
.Index(t => t.Foo_Id)
.Index(t => t.SubBar_Id);
I also tried eager loading the Foos when querying SubBars on the DbContext with don't get any errors:
我也尝试在DbContext上查询SubBars时急切加载Foos,不要出现任何错误:
var context = new FooBarContext();
var subBars = from sb in context.SubBars.Include(i => i.Foos)
select sb;
#2
I was able to reverse the naming by checking here
我可以通过在这里查看来反转命名
https://msdn.microsoft.com/en-us/library/jj591620(v=vs.113).aspx
So long as both Entity1 and Entity2 have navagational properties to eachother, then the following works.
只要Entity1和Entity2都具有彼此的导航属性,那么以下工作。
modelBuilder.Entity<Order>()
.HasMany(t => t.Products)
.WithMany(t => t.Orders);
which produces
CreateTable(
"dbo.OrderProducts",
c => new
{
Order_OrderID = c.Int(nullable: false),
Product_ID = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.Order_OrderID, t.Product_ID })
.ForeignKey("dbo.Orders", t => t.Order_OrderID, cascadeDelete: true)
.ForeignKey("dbo.Products", t => t.Product_ID, cascadeDelete: true)
.Index(t => t.Order_OrderID)
.Index(t => t.Product_ID);
#1
You can ensure the table name is generated as "FooBars" if you override the OnModelCreating method on your DbContext as follows:
如果您在DbContext上覆盖OnModelCreating方法,则可以确保将表名生成为“FooBars”,如下所示:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Foo>().HasMany(f => f.Bars).WithMany(b => b.Foos)
.Map(m =>
m.ToTable("FooBars")
// Optionally specify the key column names...
.MapLeftKey("FooId")
.MapRightKey("BarId")
);
modelBuilder.Entity<Foo>().HasMany(f => f.SubBars).WithMany(sb => sb.Foos).Map(m => m.ToTable("FooSubBars"));
}
Which will produce this in the migration:
这将在迁移中产生这种情况:
CreateTable(
"dbo.FooBar",
c => new
{
FooId = c.Int(nullable: false),
BarId = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.FooId, t.BarId })
.ForeignKey("dbo.Foos", t => t.FooId, cascadeDelete: true)
.ForeignKey("dbo.Bars", t => t.BarId, cascadeDelete: true)
.Index(t => t.FooId)
.Index(t => t.BarId);
CreateTable(
"dbo.FooSubBar",
c => new
{
Foo_Id = c.Int(nullable: false),
SubBar_Id = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.Foo_Id, t.SubBar_Id })
.ForeignKey("dbo.Foos", t => t.Foo_Id, cascadeDelete: true)
.ForeignKey("dbo.SubBars", t => t.SubBar_Id, cascadeDelete: true)
.Index(t => t.Foo_Id)
.Index(t => t.SubBar_Id);
I also tried eager loading the Foos when querying SubBars on the DbContext with don't get any errors:
我也尝试在DbContext上查询SubBars时急切加载Foos,不要出现任何错误:
var context = new FooBarContext();
var subBars = from sb in context.SubBars.Include(i => i.Foos)
select sb;
#2
I was able to reverse the naming by checking here
我可以通过在这里查看来反转命名
https://msdn.microsoft.com/en-us/library/jj591620(v=vs.113).aspx
So long as both Entity1 and Entity2 have navagational properties to eachother, then the following works.
只要Entity1和Entity2都具有彼此的导航属性,那么以下工作。
modelBuilder.Entity<Order>()
.HasMany(t => t.Products)
.WithMany(t => t.Orders);
which produces
CreateTable(
"dbo.OrderProducts",
c => new
{
Order_OrderID = c.Int(nullable: false),
Product_ID = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.Order_OrderID, t.Product_ID })
.ForeignKey("dbo.Orders", t => t.Order_OrderID, cascadeDelete: true)
.ForeignKey("dbo.Products", t => t.Product_ID, cascadeDelete: true)
.Index(t => t.Order_OrderID)
.Index(t => t.Product_ID);