How can I efficiently delete all records in a table using Entity Framework without using SQL?

Question

I need to remove all records in a given table, using a DbContext in Entity Framework. I need this to be portable, so it can't rely on SQL statements or stored procedures. I've looked through the answers to this question , but none of them meet my requirements or are ideal solutions for a variety of reasons.

I could use the RemoveRange method, ie

DbContext.Table.RemoveRange(all);

But this doesn't scale well, because it selects all entries before deleting, which could take a long, long time with Entity Framework. Iterating through each record and removing them individually with Remove(record) has the same problem.

Using SQL this is simple, using a TRUNCATE command. Even a simple DELETE FROM [TableName] command works, but I don't know how scalable that is.

Is there any solution that uses only Entity Framework (no SQL), and doesn't require selecting all records first before deleting them?

Answer 1

This is currently not something that is possible using Entity Framework. see https://github.com/dotnet/efcore/issues/795

There may be an extension out there that will allow you to do that, but I am not sure it will work will all RDBMS systems.

Answer 2

Let's suppose you have BrandData table with records about some brands:

public class BrandData
    {
        [Key]
        public int Id { get; set; }

        public string Name { get; set; }

        public string Description { get; set; }
    }

Also you've created a dbcontext:

public class MyDbContext : DbContext
    {
        public MyDbContext(DbContextOptions<MyDbContext> options) : base(options)
        {
            Database.Migrate();
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Entity<BrandData>().HasData(new BrandData { Id = 999, Name = "LG", Description = "TV brand" });
            
        }
        public DbSet<BrandData> BrandData { get; set; }

    }

Finally, this is the method that deletes brand by its ID:

public async Task DeleteModelAsync(int id)
        {
            var data = _dbContext.ModelData.FirstOrDefault(b => b.Id == id);
            if (data != null)
            {
                _dbContext.ModelData.Remove(data);
                await _dbContext.SaveChangesAsync();
            }
        }

Changes will be done after SaveChangesAsync() method run.

UPDATE

To delete all records:

    var brands = await _dbContext.BrandData.ToListAsync();
    
                    foreach(var brand in brands)
                    {
                        _dbContext.BrandData.Remove(brand);
                    }

    await _dbContext.SaveChangesAsync();