Create POCO class in EF 7 code first - entity-framework

Question

Say I have three tables. Settings, Facilities and FacilitySettingOverride in an existing database. The sample data:
Settings table
ID Name Value
1 test1 true
2 test2 true
Facilities table
ID Name
163 Demo1
164 Demo2
FacilitySettingOverride
FacilityId SettingId Value
163 2 False
164 1 False
164 2 False
FacilitySettingOverride has two foreign keys---FacilityId and SettingId. Also I want to make a composite key for FacilitySettingOverride.
I just don't know how to make it. My primary code.
[Table("Settings")]
public class Setting
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Value { get; set; }
public FacilitySettingOverride FacilitySettingOverride { get; set; }
}
[Table("Facilities")]
public class Facility
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<FacilitySettingOverride> FacilitySettingOverrides { get; set; }
}
[Table("FacilitySettingOverride")]
public class FacilitySettingOverride
{
[Key]
[ForeignKey("FacilityId")]
public int FacilityId { get; set; }
public string Value { get; set; }
[ForeignKey("SettingId")]
public int SettingId { get; set; }
public virtual Facility Facility { get; set; }
public virtual Setting Setting { get; set; }
I guess that it is wrong. Thanks for help.

Answer 1

Looking at your data and description, both Settings and Facility have one-to-many associations to FacilitySettingOverride. So Setting shouldn't have a property ...
public FacilitySettingOverride FacilitySettingOverride { get; set; }
... but a collection of FacilitySettingOverrides, just as Facility has.
This should be the proper class model:
[Table("Settings")]
public class Setting
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Value { get; set; }
public virtual ICollection<FacilitySettingOverride> FacilitySettingOverrides { get; set; }
}
[Table("Facilities")]
public class Facility
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<FacilitySettingOverride> FacilitySettingOverrides { get; set; }
}
[Table("FacilitySettingOverride")]
public class FacilitySettingOverride
{
[Key, Column(Order = 1)]
[ForeignKey("Facility")]
public int FacilityId { get; set; }
[Key, Column(Order = 2)]
[ForeignKey("Setting")]
public int SettingId { get; set; }
public virtual Facility Facility { get; set; }
public virtual Setting Setting { get; set; }
public string Value { get; set; }
}
The combination of KeyAttribute and ColumnAttribute ([Key, Column(Order = 1)]) is used for composite primary keys.
This is the database schema EF creates from it: