Force Entity Framework to update several records in one round trip.

Question

I have to update multiple records in EF and I've come up with the following two methods:

Method 1: ExecuteSqlCommand (direct SQL)

customDB.Database.ExecuteSqlCommand(
@"UPDATE  dbo.UserInfo
SET     dbo.UserInfo.Email = dbo.IAMUser.Email,
        dbo.UserInfo.Mobile = dbo.IAMUser.Phone
FROM    dbo.UserInfo
        INNER JOIN dbo.IAMUserMapping ON dbo.UserInfo.UserID = dbo.IAMUserMapping.fUserId
        INNER JOIN dbo.IAMUser ON IAMUser.IAMID = IAMUserMapping.fIAMID
WHERE   dbo.IAMUser.IAMID = @iamid ", new SqlParameter("@iamid", SqlDbType.UniqueIdentifier) { Value = IAMID });

Method 2: Linq foreach:

var ui = from userInfo in customDB.UserInfo
     join userMapping in customDB.IAMUserMapping 
         on userInfo.UserID equals userMapping.fUserId
     join iamUser in customDB.IAMUser 
         on userMapping.IAMUser.IAMID equals iamUser.IAMID
     where iamUser.IAMID == IAMID
     select new
     {
         userInfo.UserID,
         iamUser.Email,
         iamUser.Phone
     };

foreach (var x1 in ui)
{
    var u = new UserInfo
    {
        UserID = x1.UserID,
        Email = x1.Email,
        Mobile = x1.Phone
    };
    customDB.UserInfo.Attach(u);
    var entry = customDB.Entry(u);
    entry.Property(e => e.Email).IsModified = true;
    entry.Property(e => e.Mobile).IsModified = true;
}
customDB.SaveChanges();

Method #1 is the most efficient, resulting in a single SQL query.

Method #2 is as efficient on the SQL Server side of things, but it generates a lot more round trips to the server. 1 select to get the records, then 1 update for each record that is updated.

Method #2 will give a compile time error if anything in the DB is changed, while #1 will give a run time error.

What do people consider the best practice in cases like these?

Is there any way to get the best of both worlds?

Answer 1

With first approach problems that you may faced will be much more critical and harder to solve, eg when renaming/restructuring of entities. Compile time errors are much better, easy to solve then runtime ones.

Also, I am not sure how ExecuteSqlCommand method works, but looks like this code is vulnerable to SQL Injection. So, I will definitelly choose linq approach.