[英]Insert new record in pivot table with many to many relationship using Entity Framework Core
I am building an application using ASP.NET Core MVC.我正在使用 ASP.NET Core MVC 构建应用程序。 I am trying to insert a new record with a many-to-many relationship.我正在尝试插入具有多对多关系的新记录。 I have 3 tables Repairs
, Parts
and RepairParts
.我有 3 个表Repairs
, Parts
和RepairParts
。
How can I insert the RepairId
and PartId
into the RepairParts
table?如何将RepairId
和PartId
插入到RepairParts
表中? Does EF Core provide something for this? EF Core 是否为此提供了一些东西? I searched the documentation but it doesn't mention anything about how to do this.我搜索了文档,但没有提到有关如何执行此操作的任何信息。
Does Entity Framework do this automatically?实体框架会自动执行此操作吗? (insert to the pivot table) Or do I need to do it manually? (插入数据透视表)还是我需要手动完成? An example would help.一个例子会有所帮助。
Repair class:维修类:
public class Repair
{
[Key]
public int RepairId { get; set; }
public int VehicleId { get; set; }
public string Notes { get; set; }
public string Mileage { get; set; }
public DateTime RepairDate { get; set; }
public string uuid { get; set; }
[ForeignKey("VehicleId")]
public Vehicle Vehicle { get; set; }
public virtual ICollection<RepairParts> RepairParts { get; set; }
}
Part class:零件类:
public class Part
{
public int PartId { get; set; }
public int Code { get; set; }
public string PartCode { get; set; }
public string Type { get; set; }
public string Name { get; set; }
public string Descr { get; set; }
public string Manufacturer { get; set; }
public string uuid { get; set; }
public virtual ICollection<RepairParts> RepairParts { get; set; }
}
RepairPart class:维修零件类:
public class RepairParts
{
public int RepairId { get; set; }
public Repair Repair { get; set; }
public int PartId { get; set; }
public Part Part { get; set; }
public decimal price { get; set; }
}
DbContext class: DbContext类:
public class ApplicationDbContext : IdentityDbContext
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
public DbSet<Customer> Customers { get; set; }
public DbSet<TaxOffice> TaxOffices { get; set; }
public DbSet<Vehicle> Vehicles { get; set; }
public DbSet<Part> Parts { get; set; }
public DbSet<Repair> Repairs { get; set; }
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<Customer>()
.HasMany(v => v.Vehicles)
.WithOne(b => b.Customer);
builder.Entity<Vehicle>()
.HasOne(c => c.Customer)
.WithMany(b => b.Vehicles);
builder.Entity<Vehicle>()
.HasMany(v => v.Repairs)
.WithOne(c => c.Vehicle);
builder.Entity<RepairParts>()
.HasKey(t => new { t.RepairId, t.PartId });
builder.Entity<RepairParts>()
.HasOne(r => r.Repair)
.WithMany(t => t.RepairParts)
.HasForeignKey(f => f.RepairId);
builder.Entity<RepairParts>()
.HasOne(r => r.Part)
.WithMany(p => p.RepairParts)
.HasForeignKey(f => f.PartId);
}
}
Here are two options for you:这里有两个选项供您选择:
Insert RepairParts
by public virtual ICollection<RepairParts> RepairParts { get; set; }
通过public virtual ICollection<RepairParts> RepairParts { get; set; }
插入RepairParts
public virtual ICollection<RepairParts> RepairParts { get; set; }
var repaire = new Repair { uuid = "R3" }; var part = new Part { Code = 3 }; var reparePart = new RepairParts { Repair = repaire, Part = part }; repaire.RepairParts = new List<RepairParts>() { reparePart }; _context.Add(repaire); _context.SaveChanges();
Insert RepairParts
explictly by _context.Add(reparePart1);
通过_context.Add(reparePart1);
显式插入RepairParts
_context.Add(reparePart1);
var repaire1 = new Repair { uuid = "RR1" }; var part1 = new Part { Code = 4 }; var reparePart1 = new RepairParts { Repair = repaire1, Part = part1 }; _context.Add(repaire1); _context.Add(part1); _context.Add(reparePart1); _context.SaveChanges();
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