Question

我的技术问题非常简短：如何更新使用Code First Migration时创建的关系表？

此处 StockKeepingUnitFeature 表是自动创建的，但我没有任何对象类来更新该表。我们该怎么办？

protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();

            modelBuilder.Entity<StockKeepingUnit>()
            .HasMany(b => b.Feature)
            .WithMany(a => a.StockKeepingUnit)
            .Map(m => m.MapLeftKey("StockKeepingUnitId")
                          .MapRightKey("FeatureId")
                          .ToTable("StockKeepingUnitFeature"));
        }

谢谢！

Answer 1

这里的解决方案：我发现微软的链接，非常有帮助！ Relationships, Navigation Properties, and Foreign Keys

此后我的代码更新了关系表：

public IQueryable<TEntity> AllIncluding(params Expression<Func<TEntity, object>>[] includeProperties)
    {
        IQueryable<TEntity> query = context.Set<TEntity>();
        foreach (var includeProperty in includeProperties)
        {
            query = query.Include(includeProperty);
        }
        return query;
    }
/// <summary>
    /// Update the relational StockKeepingUnitFeature table
    /// </summary>
    /// <param name="stockKeepingUnitSlug"></param>
    /// <param name="featureSlug"></param>
    /// <returns></returns>
    public bool AddFeatureToStockKeepingUnit(string stockKeepingUnitSlug, string featureSlug)
    {
        StockKeepingUnit sku = this.AllIncluding(stockKeepingUnit => stockKeepingUnit.Feature).Where(s => s.Slug == stockKeepingUnitSlug).FirstOrDefault();
        Feature feature = context.Features.FirstOrDefault(f => f.Slug == featureSlug);

        if (feature != null && sku != null)
        {
            sku.Feature.Add(feature);
            context.StockKeepingUnits.Attach(sku);
            context.SaveChanges();
            return true;
        }

        return false;
    }
    /// <summary>
    /// Update the relational StockKeepingUnitFeature database
    /// </summary>
    /// <param name="stockKeepingUnitSlug"></param>
    /// <param name="featureSlug"></param>
    /// <returns></returns>
    public bool RemoveFeatureFromStockKeepingUnit(string stockKeepingUnitSlug, string featureSlug)
    {
        StockKeepingUnit sku = this.AllIncluding(stockKeepingUnit => stockKeepingUnit.Feature).Where(s => s.Slug == stockKeepingUnitSlug).FirstOrDefault();
        Feature feature = context.Features.FirstOrDefault(f => f.Slug == featureSlug);

        if (feature != null && sku != null)
        {
            context.Entry(feature).Collection(s => s.StockKeepingUnit).CurrentValue = null;
            context.SaveChanges();
            return true;
        }

        return false;
    }

希望它对社区有用，

干杯

如何使用代码首次迁移更新关系表

1 个答案: