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https://github.com/bbonkr/sample.ef.mtom
Changes many to many relation implementation in EntityFrameworkCore
https://github.com/bbonkr/sample.ef.mtom
dotnet entityframeworkcore
Last synced: 25 days ago
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Changes many to many relation implementation in EntityFrameworkCore
- Host: GitHub
- URL: https://github.com/bbonkr/sample.ef.mtom
- Owner: bbonkr
- Created: 2021-12-17T03:40:22.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2021-12-18T05:46:37.000Z (almost 3 years ago)
- Last Synced: 2024-04-09T21:56:09.084Z (7 months ago)
- Topics: dotnet, entityframeworkcore
- Language: C#
- Homepage:
- Size: 37.1 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
## Tables
### Student
| Name | Nullable | Constaint |
| :---- | :------: | :-------: |
| Id | NN | PK |
| Name | NN | |
### Cource
| Name | Nullable | Constaint |
| :---- | :-----: | :--------: |
| Id | NN | PK |
| Title | NN | |
### Enrollment
| Name | Nullable | Constaint |
| :-------- | :------: | :-------: |
| StudentId | NN | PK |
| CourseId | NN | PK |
## EntityTypeConfiguration
EntityTypeConfiguration of Enrollment entity
### .net core 3.1
```csharp
public class EnrollmentEntityTypeConfiguration : IEntityTypeConfiguration
{
public void Configure(EntityTypeBuilder builder)
{
builder.HasKey(x => new { x.StudentId, x.CourseId });
builder.Property(x => x.StudentId)
.IsRequired();
builder.Property(x => x.CourseId)
.IsRequired();
builder.HasOne(x => x.Student)
.WithMany(x => x.Enrollments)
.HasForeignKey(x => x.StudentId);
builder.HasOne(x => x.Course)
.WithMany(x => x.Enrollments)
.HasForeignKey(x => x.CourseId);
}
}
```
### .NET 5
No change
### .NET 6
Remove EnrollmentEntityTypeConfiguration class, configure in course entity type configuration
```csharp
public class CourseEntityTypeConfiguration : IEntityTypeConfiguration
{
public void Configure(EntityTypeBuilder builder)
{
builder.HasKey(x => x.Id);
builder.Property(x => x.Id)
.IsRequired()
.ValueGeneratedOnAdd();
builder.Property(x => x.Title)
.IsRequired();
builder.HasMany(x => x.Students)
.WithMany(x => x.Courses)
.UsingEntity(
j => j.HasOne(x => x.Student).WithMany(x => x.Enrollments).HasForeignKey(x => x.StudentId),
j => j.HasOne(x => x.Course).WithMany(x => x.Enrollments).HasForeignKey(x => x.CourseId),
j =>
{
j.HasKey(x => new { x.StudentId, x.CourseId });
});
}
}
```
There is No change in migrations codes after Changed entity type configuration. [20211218051811_Change mtom](https://github.com/bbonkr/sample.ef.mtom/blob/features/net6/src/Sample.Data.SqlServer/Migrations/20211218051811_Change%20mtom.cs)
## Usages
### .net core 3.1
Get student and their enrolled courses
```csharp
var students = await Context.Students
.Include(x => x.Enrollments)
.Select(student => new
{
Name = student.Name,
Courses = x.Enrollments.Select(enrollment => new
{
Title = enrollment.Course.Title,
}),
});
```
```csharp
var enrollments = Context.Courses
.ToList()
.Where((_, index) => index < value)
.Select(x => new Enrollment
{
CourseId = x.Id,
});
student.Enrollments
.AddRange(enrollments);
```
### .NET 5
No change
### .NET 6
Can access course of student enrollment directly. Does not need to access through enrollments.
```csharp
var students = await Context.Students
.Include(x => x.Courses)
.Select(student => new
{
Name = student.Name,
Courses = student.Courses.Select(course => new
{
Title = course.Title,
}),
})
```
Also, can insert course of student directly. Does not need to access through enrollments.
```csharp
var coursesToEnroll = Context.Courses
.ToList()
.Where((_, index) => index < value);
student.Courses.AddRange(coursesToEnroll);
```
## Others
### dotnet-ef tool
If install dotnet tool locally, make sure to create manifest file first.
```bash
$ dotnet new tool-manifest
```
Pelase see [nuget: dotnet-ef](https://www.nuget.org/packages/dotnet-ef/) versions tab.
.net core 3.1
```bash
$ dotnet tool install --local dotnet-ef --version 3.1.22
```
.net 5
```bash
$ dotnet tool update --local dotnet-ef --version 5.0.13
```
.net 6
```bash
$ dotnet tool update --local dotnet-ef --version 6.0.1
```
### Add migrations
```bash
$ cd src/Sample.Data
$ dotnet ef migrations add "Migrations name" --context AppDbContext --startup-project ../Sample.App --project ../Sample.Data.SqlServer
```