[英]ASP.NET Core : Fluent Api relationships configuration
网上有很多关于如何使用Fluent API的例子,但主要是展示如何配置两个模型之间的一种关系。 就我而言,我需要 2 个模型之间的 3 个关系。 如何使用 Fluent API 配置以下模型之间的关系?
public class Company
{
public int Id { get; set; }
public string Name { get; set; }
public int FinanceEstimateId { get; set; }
public Estimate FinanceEstimate { get; set; }
public int EnvironmentEstimateId { get; set; }
public Estimate EnvironmentEstimate { get; set; }
public int SelfEstimateId { get; set; }
public Estimate SelfEstimate { get; set; }
}
public class Estimate
{
public int Id { get; set; }
public string Name { get; set; } // like: bad, good, excellent
public float Value { get; set; } // like: 1,2,3
}
也许这为您指明了正确的方向。
对于 2 种配置,我会使用 go,例如:
public class CompanyConfiguration : IEntityTypeConfiguration<Company>
{
public void Configure(EntityTypeBuilder<Company> builder)
{
builder.ToTable("Companies");
builder
.HasOne(x => x.EnvironmentEstimate)
.WithMany()
.HasForeignKey(x => x.EnvironmentEstimateId)
.OnDelete(DeleteBehavior.NoAction);
builder
.HasOne(x => x.FinanceEstimate)
.WithMany()
.HasForeignKey(x => x.FinanceEstimateId)
.OnDelete(DeleteBehavior.NoAction);
builder
.HasOne(x => x.SelfEstimate)
.WithMany()
.HasForeignKey(x => x.SelfEstimateId)
.OnDelete(DeleteBehavior.NoAction);
}
}
public class EstimateConfiguration : IEntityTypeConfiguration<Estimate>
{
public void Configure(EntityTypeBuilder<Estimate> builder)
{
builder.ToTable("Estimates");
}
}
你需要一个 DbContext:
public class MyDbContext : DbContext
{
public DbSet<Company> Companies { get; set; } = null!;
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer(@"CONNECTIONSTRING");
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// applies the configuration (those IEntityTypeConfiguration<T> things)
modelBuilder.ApplyConfigurationsFromAssembly(typeof(MyDbContext).Assembly);
}
}
我创建了一个控制台应用程序来演示用法
using var ctx = new MyDbContext();
await ctx.Database.EnsureDeletedAsync();
await ctx.Database.EnsureCreatedAsync();
var company1 = new Company
{
Name = "Name1",
EnvironmentEstimate = new Estimate { Name = "EnvironmentEstimate1", Value = 1 },
FinanceEstimate = new Estimate { Name = "FinanceEstimate1", Value = 2 },
SelfEstimate = new Estimate { Name = "SelfEstimate1", Value = 3 }
};
var company2 = new Company
{
Name = "Name2",
EnvironmentEstimate = new Estimate { Name = "EnvironmentEstimate2", Value = 4 },
FinanceEstimate = new Estimate { Name = "FinanceEstimate2", Value = 5 },
SelfEstimate = new Estimate { Name = "SelfEstimate2", Value = 6 }
};
await ctx.Companies.AddAsync(company1);
await ctx.Companies.AddAsync(company2);
await ctx.SaveChangesAsync();
var result = await ctx.Companies.ToListAsync();
Console.WriteLine("Done");
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