- * Returns an appropriately quoted sequence value for inserting a new row.
- * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
- * subclass will return an integer, and save the value for insertId()
+ * Deprecated method, calls should be removed.
+ *
+ * This was formerly used for PostgreSQL and Oracle to handle
+ * self::insertId() auto-incrementing fields. It is no longer necessary
+ * since DatabasePostgres::insertId() has been reimplemented using
+ * `lastval()` and Oracle has been reimplemented using triggers.
+ *
+ * Implementations should return null if inserting `NULL` into an
+ * auto-incrementing field works, otherwise it should return an instance of
+ * NextSequenceValue and filter it on calls to relevant methods.