UserActivity log = new UserActivity();

                    ApplicationDbContext db = new ApplicationDbContext();

                    log.UserEmail = User.Identity.Name;
                    log.SQL_Query = queryString;
                    log.Query_Start = String.Format("{0:hh:mm:ss}", start);
                    log.Query_End = String.Format("{0:hh:mm:ss}", end);
                    log.Query_Time = String.Format("{0:mm:ss.ff}", Duration.ToString());

                    db.UserActivities.Add(log);

                    db.SaveChanges();

CREATE TABLE [dbo].[UserActivities] (
    [Id]            INT            NOT NULL,
    [UserEmail]     VARCHAR (255)  NOT NULL,
    [SQL_Query ]    VARCHAR (1000) NOT NULL,
    [Query_Start]   VARCHAR (11)   NULL,
    [Query_End]     VARCHAR (11)   NULL,
    [Query_Time]    VARCHAR (11)   NULL,
    [Error_Message] VARCHAR (255)  NULL,
    PRIMARY KEY CLUSTERED ([Id] ASC)
);

log.UserEmail.Length;
        21
        log.Query_End.Length;
        8
        log.Query_Start.Length;
        8
        log.SQL_Query.Length;
        32