自动生成的外键数据库

Question

在执行插入步骤时，我想在表上自动生成外键值。我尝试了NOTNULL Identity (1,1)，但是它不起作用，我想插入一篇文章，并使用3个带有数据实体的自动生成的外键。

Answer 1

这是您的课程...

• 米是实体
• MeterMap是ENTITY CONFIGURATION
• YourDbContext是数据库上下文
• YourDbContextUnitOfWork工作单位

干杯！

public partial class Meter
{
    public int MeterId { get; set; } //<-- This is the IDENTITY

    public string MeterNumber { get; set; }

    public string MeterName { get; set; }
}

public MeterMap(DbModelBuilder modelBuilder) : EntityTypeConfiguration<Meter>
{
    // Maps Table to Concrete Types
    Map(m => m.MapInheritedProperties());

    ToTable("Meter", "dbo")
        .HasKey(m => m.MeterId);

    Property(m => m.MeterId)
        .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity)
        .IsRequired();

    Property(m => m.MeterNumber)
        .HasMaxLength(20)
        .HasColumnType("varchar")
        .HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_Meter_AlternateKey", 1) { IsUnique = false }))
        .IsOptional();

    Property(m => m.MeterName)
        .HasMaxLength(50)
        .HasColumnType("varchar")
        .HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_Meter_AlternateKey", 2) { IsUnique = false }))
        .IsOptional();
}

public class YourDbContext : DbContext
{
    public YourDbContext() : base("Your.ConnectionString.Name")
    {
        Database.SetInitializer<YourDbContext>(null);
        Database.CommandTimeout = WhatEverIntegerValueYouLike;

    } 

    public virtual DbSet<Meter> Meter { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.Configurations.Add(new MeterMap(modelBuilder));
    } 
}

public sealed class YourDbContextUnitOfWork : IUnitOfWork
{
    #region <Constructors>

    public YourDbContextUnitOfWork(YourDbContext dbContext)
    {
        DbContext = dbContext
    } 

    public DbContext DbContext { get; set; }

    [SetterProperty]
    public ICompositeRepository<Meter> Meter { get; set; }

    [DebuggerStepThrough]
    public void Dispose()
    {
        // Free managed resources
        if (DbContext != null)
            DbContext.Dispose();

        GC.SuppressFinalize(this);
    }

    [DebuggerStepThrough]
    public void SubmitChanges()
    {
        DbContext.SaveChanges();
    } 
}