Flags (bit fields) which identify properties of an index.
public enum ul_index_flag
The index is a primary key.
The index is a primary key or index created for a unique constraint (nulls not allowed).
The index was created with the UNIQUE flag (or is a primary key).
The index is a foreign key.
The foreign key allows nulls.
Referential integrity checks are performed on commit (rather than on insert/update).
Syntax