public virtual string HandleDefault(IHasDefaultSource item)
 {
     return(item.DefaultSource?.ToString());
 }
        public virtual IEnumerable <Command> HandleAlterDefault(Func <string, string> alterActionFactory, IHasDefaultSource @default, IHasDefaultSource otherDefault)
        {
            if (otherDefault.DefaultSource != @default.DefaultSource)
            {
                if (otherDefault.DefaultSource != null)
                {
                    yield return(new Command().Append(alterActionFactory("DROP DEFAULT")));
                }

                if (@default.DefaultSource != null)
                {
                    yield return(new Command().Append(alterActionFactory($"SET {@default.DefaultSource}")));
                }
            }
        }