Built-in B-tree operator class
The built-in secondary-access method (the generic B-tree) has a default operator class called btree_ops, which is defined in the sysopclasses system catalog table.
By default, the CREATE INDEX statement associates the btree_ops operator
class with it when you create a B-tree index. For example, the following
CREATE INDEX statement creates a generic B-tree index on the order_date column
of the orders table and associates with this index the default
operator class for the B-tree secondary-access method:
CREATE INDEX orddate_ix ON orders (order_date)Informix® uses
the btree_ops operator class to specify:
- The strategy functions to tell the query optimizer which filters in a query can use a B-tree index
- The support function to build and search the B-tree index