+ If "indexes" is specified, it must be an array of zero or more
+ <column-set>s. A <column-set> is an array of one or more strings,
+ each of which names a column. Each <column-set> is a set of
+ columns whose values, taken together within any given row, must be
+ unique within the table. This is a "deferred" constraint,
+ enforced only at transaction commit time, after unreferenced rows
+ are deleted and dangling weak references are removed. Ephemeral
+ columns may not be part of indexes.
+