for (Index idx : indexes.value()) {
NutEntityIndex index = new NutEntityIndex();
index.setUnique(idx.unique());
index.setName(idx.name());
for (String indexName : idx.fields()) {
EntityField ef = en.getField(indexName);
if (null == ef) {
throw Lang.makeThrow("Fail to find field '%s' in '%s' by @Index(%s:%s)",
indexName,
en.getType().getName(),
index.getName(),