I have issue saving data in many-to-may relationship between two tables that breaks by introducing another table in between, containing primary keys of both. I have code first existing database approach along with repository pattern and unit of work in MVC application
and here is my model classes
Navigation_Functions
public class Navigation_Functions
{
public Navigation_Functions()
{
}
[Key]
public int Function_ID { get; set; }
[StringLength(250)]
[Required(ErrorMessage = "Required Title")]
[Display(Name = "Function Title")]
public string FunctionName { get; set; }
[Required(ErrorMessage = "Required Hierarchy Level")]
[Display(Name = "Hierarchy Level")]
public int Hierarchy_Level { get; set; }
public ICollection<Navigation_FunctionController> Navigation_FunctionController { get; set; }
}
}
Navigation_FunctionController Model
public class Navigation_FunctionController
{
public Navigation_FunctionController()
{
}
[Key]
public int ControllerID { get; set; }
[StringLength(250)]
[Required]
public string ControllerName { get; set; }
public ICollection <Navigation_Functions> Navigation_Functions { get; set; }
}
Junction Model
[Table("Navigation_FunctionInController")]
public class Navigation_FunctionInController
{
public Navigation_FunctionInController()
{
}
[Key]
public int FunctionInController_ID { get; set; }
[Key]
[ForeignKey("Navigation_Functions")]
public int Function_ID { get; set; }
[Key]
[ForeignKey("Navigation_FunctionController")]
public int ControllerID { get; set; }
public Navigation_FunctionController Navigation_FunctionController { get; set; }
public Navigation_Functions Navigation_Functions { get; set; }
}
I have generic repository for CRUD operation
public void InsertEntity(TEntity obj)
{
_DbSet.Add(obj);
}
My ViewModel
public class FunctionsNavigation_ViewModel
{
public Navigation_Functions _Navigation_Functions { get; set; }
public Navigation_FunctionController _Navigation_FunctionController { get; set; }
}
public void CreateFunctionNavigation(FunctionsNavigation_ViewModel _obj)
{
using (var _uow = new FunctionsNavigation_UnitOfWork())
{
try
{
var _navigationFunction = _obj._Navigation_Functions;
_navigationFunction.Navigation_FunctionController = new List<Navigation_FunctionController>();
_navigationFunction.Navigation_FunctionController.Add(_obj._Navigation_FunctionController);
_uow.Navigation_Functions_Repository.InsertEntity(_navigationFunction);
_uow.Save();
}
catch
{
}
}
}
if I remove following line from above code then it save new Navigation_Functions
_navigationFunction.Navigation_FunctionController.Add(_obj._Navigation_FunctionController);
following is screen shot from debug code.
I am wondering if my ViewModel are correct? secondly How Entity Framework knows that it need to put primary keys of two tables in Navigation_FunctionInController?
When your model looks like this...
public class Navigation_Functions
{
...
public ICollection<Navigation_FunctionController> Navigation_FunctionController { get; set; }
}
public class Navigation_FunctionController
{
...
public ICollection <Navigation_Functions> Navigation_Functions { get; set; }
}
...so without a Navigation_FunctionInController class, the junction table in the database (Navigation_FunctionInController) is not represented in the class model. If you have this model code first, EF will create a junction table itself. If you work database first, EF won't create a junction class and in the diagram you will see a pure many to many association, like this: *--*. But this only happens if the junction table only contains the two foreign keys, both of which comprise a compound primary key.
In your model you have an explicit junction class (probably because the table has a primary key field besides the two foreign keys). This means that the many to many association turns into a 1:n:1 association. The class model should essentially look like this...
public class NavigationFunction
{
...
public ICollection<NavigationFunctionInController> NavigationFunctionInControllers { get; set; }
}
public class NavigationFunctionController
{
...
public ICollection <NavigationFunctionInController> NavigationFunctionInControllers { get; set; }
}
public class NavigationFunctionInController
{
public int FunctionInControllerID { get; set; }
[ForeignKey("NavigationFunction")]
public int FunctionID { get; set; }
[ForeignKey("NavigationFunctionController")]
public int ControllerID { get; set; }
public NavigationFunctionController NavigationFunctionController { get; set; }
public NavigationFunction NavigationFunction { get; set; }
}
Note that the foreign key fields don't have to be part of the primary key (also not that I prefer the singular name Navigation_Function and plural names for collections, and no underscores in names).
So what happens in your code is that you have a 1:n:1 association, but you try to manage it like a m:n association by adding items directly to _navigationFunction.Navigation_FunctionController(s) . But EF doesn't track that collection, and the items are not saved.
Instead you have to create a junction class instance...
var nfic = new NavigationFunctionInController
{
NavigationFunction = obj.NavigationFunction,
NavigationFunctionController = obj.Navigation_FunctionController
};
...and save it through your repositories and UoW.
Related
My database has two tables - RuleGroups and Rules. My Entity Framework classes are the following:
public class RuleGroup
{
[Key]
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<Rule> Rules { get; set; }
}
public class Rule
{
[Key]
public Guid Id { get; set; }
public Guid RuleGroupId { get; set; }
public string Name { get; set; }
public ICollection<Condition> Conditions { get; set; }
[ForeignKey("RuleGroupId")]
public virtual RuleGroup RuleGroup { get; set; }
}
[NotMapped]
public class Condition
{
public Guid Id { get; set; }
public string Name { get; set; }
}
Class Condition is not mapped because it is being serialized and stored as JSON in Rule Table (using this example)
My DTOS are the following:
public class UpdateRuleGroupDto
{
public string Name { get; set; }
public ICollection<UpdateRuleDto> Rules { get; set; }
}
public class UpdateRuleDto
{
public string Name { get; set; }
public ICollection<UpdateConditionDto> Conditions { get; set; }
}
public class UpdateConditionDto
{
public string Name { get; set; }
}
In my Startup.cs I initialize Automapper :
AutoMapper.Mapper.Initialize(cfg =>
{
cfg.CreateMap<UpdateRuleGroupDto, RuleGroup>();
cfg.CreateMap<UpdateRuleDto, Rule>();
cfg.CreateMap<UpdateConditionDto, Condition>();
}
I have an API controller endpoint that accepts JSON PATCH document to make changes to data stored in database.
public IActionResult Patch(Guid ruleGroupId, [FromBody]JsonPatchDocument<UpdateRuleGroupDto> body)
{
RuleGroup ruleGroupFromRepo = _deviceRules.GetRuleGroup(ruleGroupId);
UpdateRuleGroupDto ruleGroupToPatch = Mapper.Map<UpdateRuleGroupDto>(ruleGroupFromRepo);
// Patching logic here
Mapper.Map(ruleGroupToPatch, ruleGroupFromRepo);
context.SaveChanges();
return NoContent();
}
The problem:
When changes are made/saved, Rules in Rule table change their/get new GUID.
Example, say we have this data in 2 Tables.
RuleGroup Table
[Id][Name]
[ddad5cac-e5a1-4db7-8167-66a6de3b8a0c][Test]
Rule Table
[Id][RuleGroupId][Name][Condition]
[17c38ee8-4158-4ecc-b893-97786fa76e13][ddad5cac-e5a1-4db7-8167-66a6de3b8a0c][Test][[{"Name":"Test"}]]
If I change field [Name] to a new value, Rules Table will look like this.
Rule Table
[Id][RuleGroupId][Name][Condition]
[ba106de8-bcbc-4170-ba56-80fe619cd757][ddad5cac-e5a1-4db7-8167-66a6de3b8a0c][Test2][[{"Name":"Test"}]]
Note that [Id] field has now a new GUID.
EDIT
#Gert Arnold made me realize that I'm not attaching entities.
I ran the following code:
foreach (var item in ruleGroupFromRepo.rules)
{
var x = _context.Entry(item).State;
}
and all the states were Added and not modified. Now I just have to figure out how to do it properly.
I want to map one table to two unrelated entities: EntityBasic and EntityAdvanced.
EntityAdvanced has extra business logic that I don't need for this one feature, and I would like to make a new Entity that only has fields from the table.
MyTable:
MyTableId : Guid
ParentId : Guid
Name : string
Description : string
Type : int
EntityBasic:
[Table("MyTable")]
public class EntityBasic
{
[Key]
public Guid MyTableId { get; set; }
public Guid ParentId { get; set }
public string Name { get; set; }
public string Description { get; set; }
public int Type { get; set; }
[ForeignKey("ParentId")]
public virtual List<EntityBasic> Entities{ get; set; }
}
EntityAdvanced:
[Table("MyTable")]
public class EntityAdvanced
{
private List<EntityAdvanced> _entities;
private List<Filter> _filters;
[Key]
public Guid MyTableId { get; set; }
public Guid ParentId { get; set }
public string Name { get; set; }
public string Description { get; set; }
public int Type { get; set; }
[ForeignKey("ParentId")]
public virtual List<EntityAdvanced> Entities
{
get { //Some complicated getter }
set { //Some complicated setter }
}
[NotMapped]
public string ImageUrl
{
get { //Some complicated getter }
set { //Some complicated setter }
}
public void SetFilters(//Some parameters)
{
//Some logic
}
}
When I do this i get this error:
The entity types 'EntityAdvanced' and 'EntityBasic' cannot share table 'MyTable' because they are not in the same type hierarchy or do not have a valid one to one foreign key relationship with matching primary keys between them.
Is there a way to do what I want?
As a base start, your EntityAdvanced should inherit EntityBasic since they share the same base set of properties. You don't need to rewrite them. Note the extends EntityBasic.
[Table("MyTable")]
public class EntityBasic
{
[Key]
public Guid MyTableId { get; set; }
public Guid ParentId { get; set }
public string Name { get; set; }
public string Description { get; set; }
public int Type { get; set; }
[ForeignKey("ParentId")]
public virtual List<EntityBasic> Entities{ get; set; }
}
[NotMapped]
public class EntityAdvanced : EntityBasic
{
//[NotMapped]
public string ImageUrl
{
get { //Some complicated getter }
set { //Some complicated setter }
}
public void SetFilters(//Some parameters)
{
//Some logic
}
}
Using inheritence, List<EntityBasic> Entities could reference EntityAdvanced objects so you don't need anymore to declare:
[ForeignKey("ParentId")]
public virtual List<EntityAdvanced> Entities
{
get { //Some complicated getter }
set { //Some complicated setter }
}
You can get usefull information about implementing inheritence with Entity Framework here.
Happy coding!
I think you can use the ability "Table Splitting" of Entity Framework 6,
Have a look at the example here: https://www.c-sharpcorner.com/UploadFile/ff2f08/table-splitting-in-entity-framework-6-code-first-approach/
So I try to create some ASP.NET project with EF Core.
I want to set propert of one entity as primary key and foreign key to another entity. The relationship is 0..1 - 1. I use DataAnnotations:
public class OfficeAssignment
{
[Key, ForeignKey("InstructorID")]
public int InstructorID { get; set; }
public Instructor Instructor { get; set; }
public string Location { get; set; }
}
But I keep getting column InstructorID as PK and InstructorID1 as FK... Any ideas, why EF behaves like that and how can I achieve my goal?
You should follow convention over configuration as much as you can. An OfficeAssignment entity should have an OfficeAssignmentId PK, like this:
public class OfficeAssignment
{
public int OfficeAssignmentId { get; set; }
//Notice that Id does not have an uppercase D
public int InstructorId { get; set; }
public string Location { get; set; }
public Instructor Instructor { get; set; }
}
However, if you don't want to follow normal conventions, the name of the property that goes in the ForeignKey attribute is the opposite of where it's declared:
public class OfficeAssignment
{
[Key, ForeignKey("Instructor")]
public int InstructorId { get; set; }
public string Location { get; set; }
public Instructor Instructor { get; set; }
}
And, if you want to keep it compile-time safe:
public class OfficeAssignment
{
[Key, ForeignKey(nameof(Instructor))]
public int InstructorId { get; set; }
public string Location { get; set; }
public Instructor Instructor { get; set; }
}
It's enough to set primary key attribute([Key]) in the OfficeAssignment class and in Instructor class we need to set such attribute:
[InverseProperty("Instructor")]
on collection of CourseAssignments. That will work as desired.
I need to create one to many relationship between two classes.Database do not contains primary or foreign keys. So i decided to create 2 views instead of 3 tables, and views also has no primary/foreign key (Changing the database schema is not allowed)
Views
[Table("Barcode")]
public partial class Barcode
{
[Column("_Barcode")]
public string _Barcode { get; set; }
[Column("_SkuRef")]
[MaxLength(16)]
public byte[] _SkuRef { get; set; }
[Key]
[Column("Id")]
public long Id { get; set; }
public string _SkuId { get; set; }
}
[Table("SKU")]
public partial class SKU
{
[Column("_Code", Order = 0)]
[StringLength(11)]
public string _Code { get; set; }
[Column("_Description", Order = 1)]
[StringLength(150)]
public string _Description { get; set; }
[Column("_ProductId", Order = 2)]
[StringLength(50)]
public string _ProductId { get; set; }
[Column("_Ref", Order = 3)]
[MaxLength(16)]
public byte[] _Ref { get; set; }
[Key]
[Column(Order = 4)]
[StringLength(36)]
public string Id { get; set; }
}
In this way, i tryed to use something like
using (SkuContext db = new SkuContext())
{
var Skutable = db.SKUs;
foreach(var s in Skutable)
{
Console.WriteLine(s.Id);
}
}
And its working well. But when im trying to add
public partial class Barcode
{
....
[ForeignKey("_SkuId")]
[Column("_SkuId")]
[StringLength(36)]
public string _SkuId { get; set; }
}
public partial class SKU
{
....
public IEnumerable<Barcode> Barcodes;
}
I'm facing
"The property '_SkuId' cannot be configured as a navigation property" error.
And my question is how to do the right thing? How to create relationship between two classes like these ?
I think you can create a one-to-many relationship between your SKU and Barcode views where one SKU has many Barcodes in the same way you would do it if it were tables. Use Fluent API to configure a one-to-many relationship between SKU and Barcode:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// one-to-many relationship
// _SkuId foreign key in Barcode
modelBuilder.Entity<Barcode>()
.HasRequired(c => c.SKU)
.WithMany(t => t.Barcodes)
.Map(m => m.MapKey("_SkuId"));
}
Update your classes like the following:
[Table("Barcode")]
public partial class Barcode
{
[Column("_Barcode")]
public string _Barcode { get; set; }
[Column("_SkuRef")]
[MaxLength(16)]
public byte[] _SkuRef { get; set; }
[Key]
[Column("Id")]
public long Id { get; set; }
// need to comment this out
//[Column("_SkuId")]
//[StringLength(36)]
//public string _SkuId { get; set; }
public virtual SKU SKU { get; set; }
}
[Table("SKU")]
public partial class SKU
{
[Column("_Code", Order = 0)]
[StringLength(11)]
public string _Code { get; set; }
[Column("_Description", Order = 1)]
[StringLength(150)]
public string _Description { get; set; }
[Column("_ProductId", Order = 2)]
[StringLength(50)]
public string _ProductId { get; set; }
[Column("_Ref", Order = 3)]
[MaxLength(16)]
public byte[] _Ref { get; set; }
[Key]
[Column(Order = 4)]
[StringLength(36)]
public string Id { get; set; }
public virtual ICollection<Barcode> Barcodes { get; set; }
}
You got error because your table does not contains foreign key. The foreign key attribute will not help cause you don't have such relationship in database.
If you are using ORM, such as Entity Framework, the solution will be to write a stored procedure and to make EF to work with it.
Another way is to implement your own business logic using classes from System.Data.SqlClient by specific reading, writing, etc..
So I consider that such an exercise does not needed in your simple situation. But if you are going just in this straight way, without changing tables, be ready for tons of documentation.
Using code first, I have some abstract classes and some classes derived from those abstracted classes.
// Abstracted Classes
public abstract class Brand
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
}
public abstract class Model
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
}
// Derived Classes
[Table("ComparisonBrand")]
public class ComparisonBrand : Brand
{
public ComparisonBrand()
{
ComparisonValues = new List<ComparisonValue>();
Models = new List<ComparisonModel>();
}
public virtual ICollection<ComparisonValue> ComparisonValues { get; set; }
public virtual ICollection<ComparisonModel> Models { get; set; }
}
[Table("ComparisonModel")]
public class ComparisonModel : Model
{
public int? BrandId { get; set; }
public int? LogoId { get; set; }
[ForeignKey("BrandId")]
public virtual ComparisonBrand ComparisonBrand { get; set; }
[ForeignKey("LogoId")]
public virtual ComparisonLogo ComparisonBrand { get; set; }
public virtual ICollection<ComparisonValue> ComparisonValues { get; set; }
}
My issue is that the migration generates foreign keys for:
ComparisonModel.Id > Models.Id
ComparisonModel.BrandId > Brands.Id
ComparisonModel.BrandId > ComparisonBrand.Id
Since ComparisonBrand.Id is a FK to Brands.BrandId, I get an error when deleting a Brand record. If I delete the ComparisonModel.BrandId > ComparisonBrand.Id relationship, however, the delete works fine.
How can I prevent a relationship from being formed between both the abstracted table and the derived table (Brands and ComparisonBrand)?
You are using the virtual keyword this causes Lazy Loading. You are telling EF to generate Foreign keys for them through this feature. Drop the virtual and you will not create the keys any longer