simply I ask this How to Map , How to ProductCustomer in the sample ??
public class ProductCustomer
{
public virtual Product Product { get; set; }
public virtual Customer Customer { get; set; }
}
and about Product and Customer :
public class Customer
{
public int Id { get; set; }
public string CustomerName { get; set; }
}
public class Product
{
public int Id { get; set; }
public string ProductName { get; set; }
public decimal Amount { get; set; }
}
thanks!
You don't need to create the ProductCustomer object.
In EF, you create your Customer and Product, and then you create collections to each. This will automatically create the proper link tables.
public class Customer
{
public int Id { get; set; }
public string CustomerName { get; set; }
public virtual List<Product> Products {get;set;}
}
public class Product
{
public int Id { get; set; }
public string ProductName { get; set; }
public decimal Amount { get; set; }
public virtual List<Customer> Customers {get;set;}
}
This is only the case, however, if your link table has no payload (has no additional data). If it does, then you will need to create the link table as an entity similar to what you originally did, but you add 1:many links in your product and customer classes to the link entity. You then have to modify your queries to query through the link table.
Related
Let's say I have a bike shops that sell various types of bikes: pro, kids, youth, leisure and any mixture. So I have a table of shops that refers/relates to a table of possible types. Now these shops also host events with the same types: events for pros, kids etc again any mixture. And so I have another table of events that also need to refer/relate to the same table of types:
I need to be able in a single quick query get a list of all bike types for a shop or event.
So I figured I'd have 3 main tables: Shops, Events, BikeTypes and two intermediate to link shops and events to bike types:
And I organized my models as:
public class BikeShop
{
public long Id { get; set; }
public string name { get; set; }
public string address { get; set; }
public string phone { get; set; }
}
public class BikeEvent
{
public long Id { get; set; }
public string name { get; set; }
public string description { get; set; }
public DateTime date { get; set; }
public string location { get; set; }
}
public class BikeType
{
public long Id { get; set; }
public string name { get; set; }
public string code { get; set; }
}
public class ShopBikeTypes
{
public long Id { get; set; }
public BikeShop shop { get; set; }
public BikeType biketype { get; set; }
}
public class EventBikeTypes
{
public long Id { get; set; }
public BikeEvent bikeevent { get; set; }
public BikeType biketype { get; set; }
}
With DataCotext:
public class DataContext : DbContext
{
public DbSet<BikeShop> Shops { get; set; }
public DbSet<BikeEvent> Events { get; set; }
public DbSet<BikeType> BikeTypes { get; set; }
public DbSet<ShopBikeTypes> ShopBikeTypes { get; set; }
public DbSet<EventBikeTypes> EventBikeTypes { get; set; }
}
Migration creates correct database structure just as my diagram. Great!
Now how do I make a straight forward query:
get list of all bike types for a shop
get list of all bike types for an event
Is my structure even correct?
Do I need some List<> in the main object models BikeShop and BikeEvent?
EF's include and theninclude seem to require some list?
This feels like such a typical scenario. What's the right way of doing this?
Thank you.
Those are the linq queries that you are asked but when i look at that your class models, i can say they are wrong. U need to define first which relation theyre having. if all of that relation has based on one-to-one, u wont gonna need any List<> in your class models. but if u have one-to-many relation,u gonna need them.
1- get list of all bike types for a shop
return DbContext.Shops
.Include(x>=x.ShopBikeTypes)
.ThenInclude(x=>x.BikeTypes).ToList();
2- get list of all bike types for an event
return DbContext.Events
.Include(x=>x.EventBikeTypes)
.ThenInclude(x=>x.BikeTypes).ToList();
3- Get all data in that relation
return DbContext.BikeTypes
.Include(x>=x.EventBikeTypes)
.ThenInclude(x=>x.Events).AsSplitQuery()
.Include(x=>x.ShopBikeTypes)
.ThenInclude(x>=x.Shops).AsSplitQuery()
.ToList();
it can be a tough query, do not try to use AsNoTracking() because it can cause Cartesian Explosion.
#BerkGarip: thank you for your help. I ended up with this models structure:
public class AShop
{
public long Id { get; set; }
public string name { get; set; }
public string address { get; set; }
public string phone { get; set; }
public List<AShopType> aTypes { get; set; }
}
public class AEvent
{
public long Id { get; set; }
public string name { get; set; }
public string description { get; set; }
public DateTime date { get; set; }
public string location { get; set; }
public List<AEventType> aTypes { get; set; }
}
public class AType
{
public long Id { get; set; }
public string name { get; set; }
public string code { get; set; }
}
public class AShopType
{
public long Id { get; set; }
public AType aType { get; set; }
}
public class AEventType
{
public long Id { get; set; }
public AType aType { get; set; }
}
In order to achieve what I needed using answer from #BerkGarip I figured out that the trick there was to have lists in the 'shop' and 'event' models to the intermediate objects which in turn have a single reference to 'type'. This way database layout is the same and it is many-to-many relationship and I can use 'include' and 'thenInclude' exactly as expected:
return await _context.AShops.Where(x => x.name == "Z")
.Include(x => x.aTypes)
.ThenInclude(y => y.aType)
.ToListAsync();
I have Employee, Address and Organization classes. below are the details
public partial class Employees
{
public Employees()
{
AddressDetails = new HashSet<AddressDetails>();
OrganizationDetails = new HashSet<OrganizationDetails>();
}
public string Id { get; set; }
public string FirstName { get; set; }
public string MiddleName { get; set; }
public string LastName { get; set; }
public ICollection<AddressDetails> AddressDetails { get; set; }
public ICollection<OrganizationDetails> OrganizationDetails { get; set; }
}
public partial class AddressDetails
{
public int Id { get; set; }
public string Address { get; set; }
public string Type { get; set; }
public string EmployeeId { get; set; }
public Employees Employee { get; set; }
}
public partial class OrganizationDetails
{
public int Id { get; set; }
public string Name { get; set; }
public string Location { get; set; }
public string EmployeeId { get; set; }
public Employees Employee { get; set; }
}
I have used fully defined relationship, you can see Employee has collections of both AddressDetails and OrganizationDetails as navigation properties. And each of them have EmployeeId and Employee in the same way.
My problem is, when i try to fetch Employee details using Include(), both AddressDetails and OrganizationDetails are loaded that's fine, but when i checked both the collections each entity has again loaded Employee information and so on.
for example: if i check AddressDetails collection which is loaded, Address object has information of Employee and again that Employee has collections of both AddressDetails and OrganizationDetails.
Please help me how can i avoid this. I don't want to remove Employee object property from AddressDetails and OrganizationDetails. is there anyway to make it work with Include().
here is the query i'm using to load these navigation properties.
List employees = _context.Employees.Include(emp => emp.AddressDetails).Include(emp => emp.OrganizationDetails).ToList();
I'm working on a cinema application which allows users to surf through movies, cinema places and allows them to buy or reserve tickets. If a user reserved a ticket online, then the ticket must be activated in 12 hours by sellerperson who also uses the same program. I need to show the ticket informations on grid and need to make editable. Here's my database classes that must be included in query and have relationship with Sale class. (I want to select objects from Sale class which includes ti's related classes: Ticket, customer, movie, status and saloon infos.
Sale Class:
public class Sale
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
[ForeignKey("CustomerId")]
public virtual Customer Customer { get; set; }
public int CustomerId { get; set; }
[ForeignKey("StatusId")]
public virtual Status Status { get; set; }
public int StatusId { get; set; }
public virtual Seller Seller { get; set; }
public DateTime SellDate { get; set; }
public double Price { get; set; }
[ForeignKey("TicketID")]
public virtual Ticket Ticket { get; set; }
public int TicketID { get; set; }
}
Ticket Class:
public class Ticket
{
public Ticket()
{
Seats = new List<Seat>();
}
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
[ForeignKey("MovieId")]
public virtual Movie Movie { get; set; }
public int MovieId { get; set; }
public virtual List<Seat> Seats { get; set; }
public virtual TimeSpan SeanceTime { get; set; }
public bool IsActive { get; set; }
public DateTime BuyDate { get; set; }
[ForeignKey("SaloonId")]
public virtual Saloon Saloon { get; set; }
public int? SaloonId { get; set; }
public string TicketNumber { get; set; }
}
Customer Class:
public class Customer
{
public Customer()
{
Sales = new List<Sale>();
CreditCards = new List<CreditCard>();
}
[Key]
public int UserID { get; set; }
public virtual List<Sale> Sales { get; set; }
public virtual User User { get; set; }
[DataType(DataType.CreditCard)]
public virtual List<CreditCard> CreditCards { get; set; }
}
User Class:
public class User
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
}
Status Class(Holds info of tickets. Bought or reserved.)
public class Status
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
public bool IsRez { get; set; }
public bool IsBuy { get; set; }
public bool IsCancel { get; set; }
public bool IsPaid { get; set; }
}
Saloon Class:
public class Saloon
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
public string Name { get; set; }
public double salePrices { get; set; }
}
Movie Class:
public class Movie
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
public string Name { get; set; }
}
I can't edit because in my select query I'm using anonymous type for selection. My query code:
var Source = entities.Sales.Where(w => w.Ticket.Saloon.CinemaPlace.ID == seller.CinemaPlace.ID).Select(s => new
{
CustomerName = s.Customer.User.Name,
CustomerSurname = s.Customer.User.Surname,
SalePrice = s.Price,
s.Status.IsBuy,
s.Status.IsCancel,
s.Status.IsPaid,
s.Status.IsRez,
MovieName = s.Ticket.BuyDate,
s.Ticket.Movie.Name,
SaloonName = s.Ticket.Saloon.Name,
s.Ticket.SeanceTime,
s.Ticket.TicketNumber
}).ToList();
RezervationsGrid.DataSource = Source3;
But in the grid, the datas couldn't be edited. Then I tried to join every single table using Linq to Entities queries but it didn't help either. Is there a way make a datasource from my related objects that allows edit option in grid? Thanks.
Anonymous types (those that you can declare via the new operator in the Select method) cannot have writable properties in .NET. That's why the grid is not editable. To take advantage of in-place editing, you need to instantiate objects of a real CLR type.
For this, you can declare a special ViewModel class with public properties that you should populate with values in the Select method using object initializer.
.Select(s => new SaleViewModel() {
CustomerName = s.Customer.User.Name,
SalePrice = Price
})
Note that you should not move the property initialisation logic to the ViewModel constructor to use it this way:
.Select(s => new SaleViewModel(s))
The object initialiser is the expression tree, which Entity Framework can translate into an SQL query. The constructor is just a method reference, so Entity Framework will reject such an expression. If you would like to use this approach, you will need to call the ToList method before the Select.
SaleViewModel can have the method accepting the DbContext class to save changes.
You also can select the Sale instances and use complex property paths in columns' field names (such as "Customer.User.Name"). This can probably help you to simplify the saving logic, as you will not need to find a model specific to a certain view model and copy modified property values.
I have two class (tables)
Person { id(primary key) , code, name, address, ...}
Order {id(primary key) , order_number, customer, create_date, description, ...}
I want to create relationship between Person.code and Order.customer (one two many).
How can I create that relationship in EF code first.
OK it has an easy solution
[Table("Person")]
public partial class Person
{
public long ID { get; set; }
[Key()]
[StringLength(10)]
public string code { get; set; }
[StringLength(100)]
public string name { get; set; }
[Column(TypeName = "text")]
public string address{ get; set; }
public ICollection<Order> Orders { get; set; }
}
and for order
[Table("Order")]
public partial class Order
{
public long ID { get; set; }
public int order_number { get; set; }
[StringLength(10)]
public string customer { get; set; }
[Column(TypeName = "text")]
public string description { get; set; }
//...
[ForeignKey("customer")]
public Library Person { get; set; }
}
I will create a new question about specification various composite keys per each navigation property.
Is it possible to store an IEnumerable<string> in Entity Framework?
I'm using code-first in ASP.NET MVC5 and I have a model that looks a little like this, but ImageUris does not appear as a column in my database (all the other properties do).
public class Product
{
[Key]
public int Id { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public string Condition { get; set; }
public decimal Price { get; set; }
public IEnumerable<string> ImageUris { get; set; }
}
PS: In case you are interested in why I'm storing Uris rather than images themselves, they are uris to Azure Storage Blobs.
You cannot save multiple records in single column of the relational database. There is no such data type that supports this.
You can create a separate table for Image Uris and then store your image Uris there.
Your entity code would look something like this:
public class Product
{
[Key]
public int Id { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public string Condition { get; set; }
public decimal Price { get; set; }
public virtual ICollection<ImageUri> ImageUris { get; set; }
}
public class ImageUri
{
[Key]
public int Id { get; set; }
public string Uri { get; set; }
}