How to perform SQL batch updates to update one property in Entity Framework Core 6 C#

I have the following code to perform an update in Azure SQL table using Entity Framework

public class DatabaseRepo
{
    private readonly UserContext _context;
    
    public DatabaseRepo(UserContext userContext)
    {
        _context = userContext;
    }        

    public async Task BatchUpdateUsersAsync(List<User> users)
    {           
        foreach (var user in users)
        {
	        var entity = await _context.Users
                                       .FirstOrDefaultAsync(item => item.Id == user.Id);
	        entity.StartDate = user.StartDate;

	        await _context.SaveChangesAsync();
	    }
    }
}

All I want to do update StartDate value of all these users. Is there a better way to do batch update?

I'm using EF Core 6

I tried this:

public async Task BatchUpdateUsersAsync(List<User> users)
{
        foreach (var user in users)
        {                
            var entry = _context.Set<User>().Add(user);
            entry.State = EntityState.Modified;
        }

        await _context.SaveChangesAsync();
}

but this throws an error about some other property can't be null.

EF Core 7 introduces new bulk update features, including update and delete.
Info from Microsoft: ExecuteUpdate and ExecuteDelete

You can use the following:

var dateTime = DateTime.Now;
_context.Users
       .Where(p => p.IsActive || p.Username == "DoNotUpdateMe")
       .ExecuteUpdate(p => p.SetProperty(x => x.StartDate, x => dateTime));
      _context.SaveChanges();

Attach Updates only Required column's those are IsModified =true code will be as follows

   public async Task BatchUpdateUsersAsync(List<User> users)
    {
        foreach (var user in users)
        {
            _context.Set<User>().Attach(user);
            _OSTContext.Entry(user).Property(x => x.StartDate).IsModified = true; //updates only Startdate Column
        }

        await _context.SaveChangesAsync();
    }

This will be use any Entity Frame work version

You can use the Select method for batch updates, the performance values ​​in the documentation are shared below.

More Info

public class DatabaseRepo
{
    private readonly UserContext _context;
    
    public DatabaseRepo(UserContext userContext)
    {
        _context = userContext;
    }        

    public async Task BatchUpdateUsersAsync(List<User> users)
    {           
        var entities = users.Select(async (user) => await _context.Users.FirstOrDefaultAsync(item => item.Id == user.Id));
        entities.ExecuteUpdate(p => p.SetProperty(u => u.StartDate, u => DateTime.Now));
        await _context.SaveChangesAsync();
    }
}