I am working on Entity Framework Core Code First approach and ASP.Net Core 2.1 making 3 tables:
Person class
public class Person
{
public string Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public PeopleProfessions PeopleProfessions { get; set; }
}
Professions' class
public class Profession
{
public string Id { get; set; }
public string Name{ get; set; }
public PeopleProfessions PeopleProfessions { get; set; }
}
peopleprofessions' class
public class peopleprofessions
{
[ForeignKey("PersonId ")]
public string PersonId { get; set; }
public ICollection<Person> People { get; set; }
[ForeignKey("ProfessionId")]
public string ProfessionId{ get; set; }
public ICollection<Profession> Professions { get; set; }
}
On my Context:
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<peopleprofessions>().HasKey(up => new { up.PersonId, up.ProfessionId });
}
Bearing this in mind:
People can have multiple professions.
The professions table is only for reading stored data like "Accountant".
I have doubts about how I can make table 3 only contain the foreigners and that it can meet the needs that I just mentioned.
I have tried to make the relationship appropriately but I also noticed that in tables 1 and 2 it requests both Id of the table people's professions.
I don't know if I am lost or if I am looking wrong or if there is an alternative to that situation. Thanks for any help you can give me.
You have the use of Collections on the navigation items a bit backwards. For your primary entities (Person and Profession), they should have collections, since it's one-to-many. But for the PeopleProfessions, each record is a single link to a specific entity, so no collection there just a direct object reference.
public class Person
{
public string Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public ICollection<PeopleProfessions> PeopleProfessions { get; set; }
}
public class Profession
{
public string Id { get; set; }
public string Name{ get; set; }
public ICollection<PeopleProfessions> PeopleProfessions { get; set; }
}
public class PeopleProfessions
{
public string PersonId { get; set; }
public Person Person { get; set; }
public string ProfessionId { get; set; }
public Profession Profession { get; set; }
}
You can, but don't need to specify a ForeignKey attribute because you are following EFs naming conventions(it will figure it out for you). Your OnModelCreating looks correct for the composite key.
You may want to consider removing the plural from PeopleProfessions (just call the class PeopleProfession) since one instance represents a single People-Profession relationship. I typically do this and but the navigation name in the entities remains plural, since it can represent more than one, i.e.
public ICollection<PeopleProfession> PeopleProfessions { get; set; }
Related
I'm trying to build a recipe app for my spouse. I'm trying to set it up so she can add new recipes to the database as the app grows.
When adding new recipe, she will have three drop-down to pick from to construct her new recipe ingredients. First one will contain a list of ingredients that she can choose from, the second one a list of measuring units and the third one a list of quantities.
Here is what I got so far. Am I heading in the right direction or am I off? I'm using Entity Framework with a code-first approach:
public class Recipes
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public string Image { get; set; }
}
public class Units model
{
[Key]
public int Id { get; set; }
public string UnitName { get; set; }
}
public class UnitQty
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
}
public class IngredientsModel
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
}
public class RecipeIngredients
{
public int Id { get; set; }
public int RecipesId { get; set; }
[ForeignKey("RecipesId")]
public Recipes Recipes { get; set; }
public int IngredientsModelId { get; set; }
[ForeignKey("IngredientsModelId")]
public IngredientsModel IngredientsModel { get; set; }
public int UnitQtyId { get; set; }
[ForeignKey("UnitQtyId")]
public UnitQty UnitQty { get; set; }
public int UnitsModelId { get; set; }
[ForeignKey("UnitsModelId")]
public UnitsModel UnitsModel { get; set; }
}
After creating the table, controller and the views, this is what I get in the recipe ingredients index view.
Any suggestion will be more than welcome please and thank you
RecipeIngredient class's view
First of all. You are over engineering your domain model. On relational databases Join is bottleneck you should prevent from joins if it doesn't helps you.
public class Recipt
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public string Image { get; set; }
public ICollection<RecipeIngredient> Ingredients { get; set; }
}
public class IngredientModel
{
public int Id { get; set; }
public string Name { get; set; }
public IngredientUnit UnitType { get; set; } // Unit model is best to be added here. if it doesn't change in a single IngredientModel.
}
public class RecipeIngredient
{
public int Id { get; set; }
public int UnitQuantiy { get; set; } // No need to more classes.
public IngredientModel Model { get; set; }
public Recipt Recipt { get; set; }
}
public Enum IngredientUnitType // Same Unit Model but less database relation as its small finite collection.
{
Killogram,
Count,
....
}
and according to the Microsoft documents its best to use fluentApi configuration for the relations.
Override this method in your Context:
protected override void OnModelCreating(ModelBuilder builder)
{
builder.Entity<Recipt>.HasMany(P => P.Ingredients).WithOne(P => P.Recipt);
builder.Entity<RecipeIngredient>.HasOne(P => P.Model);
// There is no need to explicit foreign key definition. but you can explicitly define your foreign keys.
}
And for the last part. in Views you can use extra models called ViewModels.
As above domain turned to a minimal domain you just need to pass a list of IngredientModels to your view to complete your View.
Just been writing up my models and dbcontext using a code first approach for EFCore and i've hit a small problem... specifically with classes and generating migrations.
It seems with entityframework any class is seen as an entity/table (my assumptions so far) but what if I want a class to be a list of fields extended onto my entity?
For example:
public class Person {
public int Id { get; set; }
public string Name { get; set; }
public Address AddressDetails { get; set; }
}
public class Address {
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public string AddressLine3 { get; set; }
public string City { get; set; }
public string County { get; set; }
public string PostCode { get; set; }
}
How can I mark the address class as additional fields to the person entity as opposed to a separate entity?
Cheers,
Mark
I'm a newbie to designing database.
I have problem how to define a domain class which has multiple foreign keys linked with a same primary key.
Here is my model:
namespace OceanFmsSystem.Domain
{
public class ExportTemplate
{
public int Id { get; set; }
public List<ExportBooking> ExportBookings { get; set; }
public string TemplateName { get; set; }
public int CustomerId { get; set; }
public string Incoterms { get; set; }
public string IncotermsDetail { get; set; }
public string PaymentTerm{ get; set; }
public int CountryOriginId { get; set; }
public int CountryDestinationId { get; set; }
}
}
What I want to do is that CountryOriginId & CountryDestinationId should refer to the below class as foreign keys:
namespace OceanFmsSystem.Domain
{
public class Country
{
public int Id { get; set; }
public string CountryCode { get; set; }
public string CountryName { get; set; }
}
}
As far as I know, in EF Core there is an convention which I should name a foreign key as below for migration from code to database.
public type ClassNameOfPrimaryKeyId { get; set;}
Is there any possible way to make this happens?
Yes, possible. Your class should look like this:
public class ExportTemplate
{
//...
public int CountryOriginId { get; set; }
public Country CountryOrigin { get; set; }
public int CountryDestinationId { get; set; }
public Country CountryDestination { get; set; }
}
EF is smart enough to figure the Ids by convention. If you do not wish to follow the convention you can use [ForeignKey] attribute on the properties to configure the FK:
[ForeignKey("Origin")]
public int MyOriginId { get; set; }
public Country Origin { get; set; }
I am working on modeling a Contact Info Structure and haven't quite figured out how the relationships should be coded with EF Core. I am fairly new to using EF for data access layer.
I want to have a contact model which can contain Website, Phonenumbers, Emails, or Social Info. Then the contact info will be added to several different models. Any suggestions would be helpful, I am not sure how code this One to many with many table relationship or if it is even possible using EF.
Models so far
public class Contact
{
public String Id { get; set; }
public Int32 ContactType { get; set; } //Enum for Website, Phonenumbers, Emails, or Social
public String RecId { get; set; } //FK to multiple Models
public String RecType { get; set; }//Value for which model the RecID is for
public String Name { get; set; }
public String Value { get; set; }
}
public class ContactInfo
{
public virtual IList<Contact> Website { get; set; }
public virtual IList<Contact> PhoneNumbers { get; set; }
public virtual IList<Contact> Emails { get; set; }
public virtual IList<Contact> Socials { get; set; }
}
//Example of models to use the contact model
public class Company
{
....
pubic ContactInfo ContactInfo { get; set;}
}
public class Client
{
....
pubic ContactInfo ContactInfo { get; set;}
}
If I understand your question correctly, then you could use following code sample, but it is not exactly what you are trying to achieve. This may give you some understanding what you need to do with EF.
public class Contact
{
public String Id { get; set; }
public ContactType ContactType { get; set; } //Enum for Website, Phonenumbers, Emails, or Social
public String RecId { get; set; } //FK to multiple Models (This can't be the FK to multiple table as it should be FK for one table so that FK for Company would be CompanyId, FK for the Client should ClientId)
public String RecType { get; set; }//Value for which model the RecID is for (This need to rethink as it may not needed.)
public String Name { get; set; }
public String Value { get; set; }
// One to Many Relationship
public string CompanyId? { get; set; }
public string ClientId? { get; set; }
public Company Company { get; set; }
public Client Client { get; set; }
}
public class Company
{
public String Id { get; set; }
// Other properties
// One to Many Relationship
public ICollection<Contact> Contacts { get; set; }
}
public class Client
{
public String Id { get; set; }
// Other properties
// One to Many Relationship
public ICollection<Contact> Contacts { get; set; }
}
/* Db context */
public class YourDbContext : DbContext
{
public YourDbContext(DbContextOptions<YourDbContext> options)
: base(options)
{
}
public virtual DbSet<Contact> Contacts { get; set; }
public virtual DbSet<Company> Companies { get; set; }
public virtual DbSet<Client> Clients { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Contact>().HasKey(t => t.Id);
modelBuilder.Entity<Company>().HasKey(t => t.Id);
modelBuilder.Entity<Company>().HasMany(c => c.Contacts).WithOne(c => c.Company).HasForeignKey(k => k.CompanyId);
modelBuilder.Entity<Client>().HasKey(t => t.Id);
modelBuilder.Entity<Client>().HasMany(t => t.Contacts).WithOne(c =>c.Client).HasForeignKey(k => k.ClientId);
}
}
/* Db context - Endd */
public enum ContactType
{
Website,
PhoneNumbers,
Emails,
Social
}
Let me know if you need anymore information.
With the help from DSR, this is the solution I have (untested).
public class Company
{
public String Id { get; set; }
public String Name { get; set; }
public ICollection<ContactPhone> PhoneNumbers { get; set; }
public ICollection<ContactEmail> ContactEmail { get; set; }
public ICollection<ContactWebsite> ContactWebsite { get; set; }
public ICollection<ContactSocial> ContactSocial { get; set; }
}
public class Client
{
public String Id { get; set; }
public String Name { get; set; }
public ICollection<ContactPhone> PhoneNumbers { get; set; }
public ICollection<ContactEmail> ContactEmail { get; set; }
public ICollection<ContactWebsite> ContactWebsite { get; set; }
public ICollection<ContactSocial> ContactSocial { get; set; }
}
public class ContactWebsite
{
public String Id { get; set; }
public String Url { get; set; }
public Company Company { get; set; }
public Client Client { get; set; }
}
public class ContactPhone
{
public String Id { get; set; }
public String Type { get; set; }
public String Number { get; set; }
public Company Company { get; set; }
public Client Client { get; set; }
}
public class ContactEmail
{
public String Id { get; set; }
public String Category { get; set; }
public String Email { get; set; }
public Company Company { get; set; }
public Client Client { get; set; }
}
public class ContactSocial
{
public String Id { get; set; }
public String Site { get; set; }
public String Handle { get; set; }
public Company Company { get; set; }
public Client Client { get; set; }
}
There is a doubt as of how to query or retrieve a value from an object stored in an document as follows in raven db.
class User
{
public String Id { get; set; }
public AccountType AccountType { get; set; }Servicetax
public String MainAccountMobileNo { get; set; }
public UserStatus Status { get; set; }
public String EmailId { get; set; }
public String DisplayName { get; set; }
public Object User { get; set; }
}
Here i am storing three different types of classes into the object User.
Say Customer,Retailer and Trader.
Customer
{
public String Name{ get; set; }
public String Address { get; set; }
public String MobileNo { get; set; }
public String EmailId { get; set; }
}
Retailer
{
public String Name{ get; set; }
public String Address { get; set; }
public String MobileNo { get; set; }
public String EmailId { get; set; }
}
Trader
{
public String Name{ get; set; }
public String Address { get; set; }
public String MobileNo { get; set; }
public String EmailId { get; set; }
}
Now is it possible to retrieve results based on the Customer's class detail?
That is now i want to retrieve All the Customers based on Address in the customer class, So how will i do it? How to typecast the object user in the query to type customer.
Thanks.
The user object in the document can store any type of class's object like account info trader in the above image. So how can i query from the object type that cannot is not definite and changing.
var Result = sess.Query<UserAccountInfo>().Where(x => x.AccountType == usertype && ((AccountInfoCustomer)x.User).Customerstatus == CustomerStatus.Pending);
This is the query that's been tried and this is the exception that's been caught
{"Url:
\"/indexes/dynamic/UserAccountInfos?query=AccountType%253ADistributor%2520AND%2520User).Customerstatus%253APending&start=0&pageSize=128&aggregation=None\"\r\n\r\nSystem.ArgumentException:
The field ')_Customerstatus' is not indexed, cannot query on fields
that are not indexed\r\n at
Raven.Database.Indexing.Index.IndexQueryOperation.AssertQueryDoesNotContainFieldsThatAreNotIndexes()
The problem here was the build of raven db. i was using the older build after changing it to newer version the query
var Result = sess.Query<UserAccountInfo>().Where(x => x.AccountType == usertype && ((AccountInfoCustomer)x.User).Customerstatus == CustomerStatus.Pending);
works fine.
Your classes are not very DRY. Consider this instead:
public abstract class Person
{
public string Name{ get; set; }
public string Address { get; set; }
public string MobileNumber { get; set; }
public string EmailAddress { get; set; }
}
public class Customer : Person {}
public class Retailer : Person {}
public class Trader : Person {}
Then, in your User class replace
public Object User { get; set; }
With this:
public Person Person { get; set; }
That way, you can store an instance of any of the 3 derived types. I wouldn't call the property User given that the containing class is called User and User.User could get confusing to anyone having to understand your code.