Am trying to understand problem in how to store every user date like ( comments ,questions,....etc ) ... or when having list of requernmints and we need to store each user checklist of the requirement separately.... i though of the following example :
here an example :
I have list of Questions related to Subject. Then Student will be able to chose subject and view list of the question and answer them.
teacher then can come and see the questions answered for every students in separate view .
How to design the model and the view so that I will be able to store each student Answers!! so teacher can come then and see view students list under his subject and can chose a student to check his answer of the question....
Here my model classes and relations,I don't know the logic of design it .... please guide me!
I hope I explained well
public class Subject
{
[Key]
public int SubjectID { get; set; }
public string SubjectName { get; set; }
public virtual ICollection<Questions> Questions { get; set; } ;
}
public class Teacher
{
[Key]
public int TeacherID { get; set; }
public string TeacherName { get; set; }
public virtual ICollection<Subjects> Subjects { get; set; } ;
}
public class Students
{
[Key]
public int StudentID { get; set; }
public string StudentName { get; set; }
public virtual ICollection<Answer> Answer{ get; set; } ;
}
public class Questions
{
[Key]
public int QuestionsID { get; set; }
public string TheQuestion { get; set; }
public virtual Subject Subject { get; set; }
}
public class Answer
{
[Key]
public int AnswerID { get; set; }
public string TheAnswer { get; set; }
public virtual Subject Subject { 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.
I am creating API in ASP .NET Core that will retrieve posts with user Id. Post should contain text and Id of a user who posted it.
I have two models Users and Posts and I need help on how to configure this relationship
I want one User to have many posts
Currently my user model contains
public class User
{
public int Id { get; set; }
public string Username { get; set; }
public List<Post> Posts { get; set; }
}
And my Post model
public class Post
{
public int Id { get; set; }
public string Text { get; set; }
}
What is the best way to do this ?
One to many relationships ( User to have many posts).
public class User{
public int Id { get; set; }
public string Username { get; set; }
public List<Post> Posts { get; set; }
}
public class Post
{
public int Id { get; set; }
public string Text { get; set; }
//Navigation
public int UserId { get; set; }
public User User{ get; set; }
}
this is your Model Class:
public class User
{
public int Id { get; set; }
public string Username { get; set; }
public Virtual List<Post> Posts { get; set; }
}
public class Post
{
public int Id { get; set; }
public string Text { get; set; }
public int UserId { get; set; }
public Virtual User User { get; set; }
}
and in your DbContext:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// configures one-to-many relationship
modelBuilder.Entity<User>().HasMany(x=>x.Posts).WithRequired(x=>x.User)
.HasForeignKey<int>(s => s.UserId);
}
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; }
I have a requirement that I am not sure how to accomplish, in my existing data I have a list of customers, each customer should be assigned a staffMember to work with them, so would this be a 1 to 1 relationship or a 1 to many relationship, having trouble wrapping my head around how to model the data, as I want to figure out how to model this correctly. Since a staff member can be assigned to many different customers How should I model this? Does this look correct?
What I would like is to have the form pull the list of staff members available from the staff table, when inputting a new customer, ideally by the name
which I figure I could probably do using linq..
public class Customer
{
public int CustomerId { get; set; }
public string Name { get; set; }
public string BusinessName { get; set; }
public string Phone { get; set; }
public string Email { get; set; }
public DateTime RequestDate { get; set; }
public Staff Staff { get; set; }
public List<CustomerJob> CustomerJobs { get; set; }
}
public class Staff
{
public int ID { get; set; }
public string Name { get; set; }
public string Phone { get; set; }
public string EMail { get; set; }
public int CustomerId { get; set; }
}
Customer have exactly 1 Staff while a single Staff maybe assigned to more than 1 Customer. So this is a one-to-many relation.
It is better that Customer be aware of its Staff. It could be called AssignedStaff. Staff itslef does not need to have a property to show all its Csutomers. Tough you can extract Customer list of a Staff using a simple query.
My recommended class structure is as follow:
public class Customer
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string BusinessName { get; set; }
public string Phone { get; set; }
public string Email { get; set; }
public DateTime RequestDate { get; set; }
public Staff AssignedStaff { get; set; }
public List<CustomerJob> CustomerJobs { get; set; }
}
public class Staff
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Phone { get; set; }
public string EMail { get; set; }
}
A query for extracting Customer list of a Staff:
var customers = _dbContext.Customers.Where(x => x.AssignedStaff.Id == staffId);
I'm having a bit of an issue mapping this out to my model. I have a Question model that represents (obviously) a question, and a QuestionType that represents the types of questions possible (text, multiple choice, list, multi-line text, and so on...).
The issue i'm having right now is trying to set the options associated with each of QuestionType Model back to the Question Model. So for example, if the QuestionType was a list type, and the list contained three elements, i'm trying to join those elements back on the Question model. The problem i'm having is that not all Questions need to have the QuestionOptions variable set. For example, for just a simple text question (not shown in code).
Any suggestions on how to achieve this?
Question Model
[Table("Questions")]
public class Question {
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int QuestionId { get; set; }
[Required]
public String Question { get; set; }
public int QuestionTypeId { get; set; }
[ForeignKey("QuestionTypeId")]
public virtual QuestionType QuestionType { get; set; }
public virtual ICollection<QuestionOptions> QuestionOptions { get; set; }
}
QuestionType Model
[Table("QuestionTypes")]
public class QuestionType {
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int QuestionTypeId { get; set; }
[Required]
public String QuestionType { get; set; }
}
QuestionOptions Model
public abstract class QuestionOptions {
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int OptionId { get; set; }
public int? QuestionId { get; set; }
[ForeignKey("QuestionId")]
public virtual Question Question { get; set; }
}
[Table("questionType_List")]
public class ListQuestion : QuestionOptions {
[Required]
public String Item { get; set; }
}
QuestionContext
public class QuestionContext : DbContext {
public QuestionContext() : base("DefaultConnection") { }
protected override void OnModelCreating(DbModelBuilder modelBuilder) {
Database.SetInitializer<QuestionContext>(null);
public DbSet<Question> Questions { get; set; }
public DbSet<QuestionType> QuestionTypes { get; set; }
public DbSet<ListQuestion> ListQuestions { get; set; }
}
Personally I would have QuestionOptions for all questions, even if that was a blank entry in the table or perhaps some sort of identifier that allows you to know if its multi-line or single line text.