C# 为表名添加前缀会导致删除鉴别器列
我有一个相当简单的查找表C# 为表名添加前缀会导致删除鉴别器列,c#,entity-framework,entity-framework-6,C#,Entity Framework,Entity Framework 6,我有一个相当简单的查找表 public class LookupType : Entity { public LookupType() { } public LookupType(string value) { Value = value; } public string Value { get; set; } // A few other properties } 以及从中继承的几个类 public cla
public class LookupType : Entity
{
public LookupType()
{
}
public LookupType(string value)
{
Value = value;
}
public string Value { get; set; }
// A few other properties
}
以及从中继承的几个类
public class SomeType : LookupType
{
public SomeType()
{
}
public SomeType(string value)
: base(value)
{
}
}
在OnModelCreating
方法中,我还有以下查找类型的映射
// Lookup Types
modelBuilder.Entity<LookupType>()
.Map<SomeType>(m => m.Requires("LookupType").HasValue("Some Type"));
但是,我需要在表名前加前缀。因此,在上下文的OnModelCreating
方法中,我添加了以下行
modelBuilder.Types().Configure(entity => entity.ToTable("abc_" + entity.ClrType.Name));
创建迁移时,LookupType
列现在不存在了
CreateTable(
"dbo.abc_LookupType",
c => new
{
Id = c.Int(nullable: false, identity: true),
DisplayOrder = c.Int(nullable: false),
Value = c.String(),
TimeStamp = c.Binary(nullable: false, fixedLength: true, timestamp: true, storeType: "rowversion"),
})
.PrimaryKey(t => t.Id);
我知道前缀配置是导致问题的原因,因为注释掉它并重新生成迁移将使LookupType列返回
列定义不应该更改,那么为什么要删除鉴别器列呢?有没有办法让我保留discriminator列并为表添加前缀?我认为您需要在OnModelCreating中指定每个层次结构的表(TPH)继承:
public class FooDb : DbContext
{
public FooDb()
: base("name=DefaultConnection")
{ }
public DbSet<BarTypeA> BarTypesA { get; set; }
public DbSet<BarTypeB> BarTypesB { get; set; }
public DbSet<BarTypeC> BarTypesC { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Foo>()
.Map<LookupType>(m => m.Requires("xyx" + "FooType").HasValue("L"))
.Map<BarTypeA>(m => m.Requires("xyx" + "LookupType").HasValue("A"))
.Map<BarTypeB>(m => m.Requires("xyx" + "LookupType").HasValue("B"))
.Map<BarTypeC>(m => m.Requires("xyx" + "LookupType").HasValue("C"));
}
}
控制台应用程序
static void Main(string[] args)
{
using (var db = new FooDb())
{
List<Foo> foos = new List<Foo>(){
new BarTypeA ("peanutsA"){ DisplayOrder=100,Package="packA"},
new BarTypeA ("olivesA"){ DisplayOrder = 101,Package="packB" },
new BarTypeB ("peanutsB"){ DisplayOrder = 200,Package="packC" },
new BarTypeB ("olivesB"){ DisplayOrder = 201,Package="packD" },
new BarTypeC ("peanutsC"){ DisplayOrder = 300,Package="packE" },
new BarTypeC ("olivesC"){ DisplayOrder = 301,Package="packF" }
};
db.BarTypesA.Add((BarTypeA)foos[0]);
db.BarTypesA.Add((BarTypeA)foos[1]);
db.BarTypesB.Add((BarTypeB)foos[2]);
db.BarTypesB.Add((BarTypeB)foos[3]);
db.BarTypesC.Add((BarTypeC)foos[4]);
db.BarTypesC.Add((BarTypeC)foos[5]);
db.SaveChanges();
}
Console.WriteLine("Press any key to end");
Console.ReadLine();
}
希望微软能找到资源,彻底记录和提供样本,因为EF似乎如此强大。不确定上述内容是否适合您的场景,但肯定会生成一个有用的鉴别器列xyzLookupType。db迁移文件调试/obj缓存不同步时出现问题。仍在寻找良好的文档/书籍。
我不完全理解为什么没有将描述添加到表中,可能是因为我添加的是BarTypes,而不是根类型(可能需要虚拟属性)。还可能需要为祖先添加数据库集…显然,如果实体框架不切换到“表/类型”,则无法在表/层次结构继承上指定任何自定义映射详细信息 最简单的修复方法就是添加
.ToTable(“abc\U LookupTypes”)
//查找类型
modelBuilder.Entity()
.Map(m=>m.Requires(“LookupType”).HasValue(“某些类型”))
.ToTable(“abc_LookupTypes”);
然后实体框架切换回TPH。与上面的行重复,但它不必在上下文文件中添加继承的类型
public class Foo
{
public int Id { get; set; }
public int DisplayOrder { get; set; }
public string Description { get; set; }
public string Package { get; set; }
public Byte[] TimeStamp { get; set; }
}
public class LookupType : Foo
{
public LookupType(){}
public LookupType(string value)
{
Description = value;
}
public string Description { get; set; }
// A few other properties
}
public class BarTypeA : LookupType
{
public BarTypeA() { }
public BarTypeA(string value) : base(value) { }
}
public class BarTypeB : LookupType
{
public BarTypeB() { }
public BarTypeB(string value) : base(value) { }
}
public class BarTypeC : LookupType
{
public BarTypeC() { }
public BarTypeC(string value) : base(value) { }
}
static void Main(string[] args)
{
using (var db = new FooDb())
{
List<Foo> foos = new List<Foo>(){
new BarTypeA ("peanutsA"){ DisplayOrder=100,Package="packA"},
new BarTypeA ("olivesA"){ DisplayOrder = 101,Package="packB" },
new BarTypeB ("peanutsB"){ DisplayOrder = 200,Package="packC" },
new BarTypeB ("olivesB"){ DisplayOrder = 201,Package="packD" },
new BarTypeC ("peanutsC"){ DisplayOrder = 300,Package="packE" },
new BarTypeC ("olivesC"){ DisplayOrder = 301,Package="packF" }
};
db.BarTypesA.Add((BarTypeA)foos[0]);
db.BarTypesA.Add((BarTypeA)foos[1]);
db.BarTypesB.Add((BarTypeB)foos[2]);
db.BarTypesB.Add((BarTypeB)foos[3]);
db.BarTypesC.Add((BarTypeC)foos[4]);
db.BarTypesC.Add((BarTypeC)foos[5]);
db.SaveChanges();
}
Console.WriteLine("Press any key to end");
Console.ReadLine();
}
CreateTable(
"dbo.Foos",
c => new
{
Id = c.Int(nullable: false, identity: true),
DisplayOrder = c.Int(nullable: false),
Description = c.String(),
Package = c.String(),
TimeStamp = c.Binary(),
xyxFooType = c.String(maxLength: 128),
xyxLookupType = c.String(maxLength: 128),
})
.PrimaryKey(t => t.Id);
// Lookup Types
modelBuilder.Entity<LookupType>()
.Map<SomeType>(m => m.Requires("LookupType").HasValue("Some Type"))
.ToTable("abc_LookupTypes");