entity framework - Code First design for 3 tables (one-to-one) -
i trying create database tracking parcel being mailed. stuck on trying figure out best way implement relationship between parcel , location @ given time/date. ultimately, need able @ moment in past , tell parcel , @ time/date. when entered location, , when left location.
i have 3 tables this. (shortened basics)
public class parcel { public int parcelid { get; set; } public virtual location location { get; set; } } public enum locationtype { warehouse, truck } public class location { [key, foreignkey("parcel")] public int parcelid { get; set; } public locationtype locationtype { get; set; } public virtual parcel parcel { get; set; } } locationtimedate { } i not sure how relate locationtimedate location. think should one-to-one relationship. i'd have have locationid. location's key foreignkey (parcel).
am going correct way? thoughts/guidance appreciated.
this is, me, case many-to-many relationship additional information (location, timedate, , parcel). parcel can have many locations (at different times), , location might belong many parcels (at different times). hope understand correctly.
here suggested design:
public class parcel { public int parcelid { get; set; } public list<parcelassignment> parcelassignments { get; set; } } public class location { [key] public int locationid { get; set; } public locationtype locationtype { get; set; } public list<parcelassignment> parcelassignments { get; set; } } public enum locationtype { warehouse, truck } public class parcelassignment { [key] public int parcelassignmentid { get; set; } [required] public int locationid { get; set; } [foreignkey("locationid")] public location location { get; set; } [required] public int parcelid { get; set; } [foreignkey("parcelid")] public parcel parcel { get; set; } public datetime dateofassignment { get; set; } } your fluent api goes dbcontext class:
modelbuilder.entity<parcelassignment>() .hasrequired(pa => pa.parcel) .withmany(p => p.parcelassignments) .hasforeignkey(pa => pa.parcelid); modelbuilder.entity<parcelassignment>() .hasrequired(pa => pa.location) .withmany(l => l.parcelassignments) .hasforeignkey(pa => pa.locationid); you can read more many-to-many relationships on ef here: