private static Dictionary <string, List <Schema.Column> > MapFromNames(Schema schema, IEnumerable <KeyValuePair <ColumnRole, string> > roles, bool opt = false)
{
Contracts.AssertValue(schema);
Contracts.AssertValue(roles);
var map = new Dictionary <string, List <Schema.Column> >();
foreach (var kvp in roles)
{
Contracts.AssertNonEmpty(kvp.Key.Value);
if (string.IsNullOrEmpty(kvp.Value))
{
continue;
}
var info = schema.GetColumnOrNull(kvp.Value);
if (info.HasValue)
{
Add(map, kvp.Key.Value, info.Value);
}
else if (!opt)
{
throw Contracts.ExceptParam(nameof(schema), $"{kvp.Value} column '{kvp.Key.Value}' not found");
}
}
return(map);
}