Creating operator classes

Finally, all the components are in place, and it is possible to create the operator class that's needed by the index:

CREATE OPERATOR CLASS sva_special_ops 
FOR TYPE text USING btree 
AS 
   OPERATOR 1 <# , 
   OPERATOR 2 <=# , 
   OPERATOR 3 = , 
   OPERATOR 4 >=# , 
   OPERATOR 5 ># , 

   FUNCTION 1 si_same(text, text);

The CREATE OPERATOR CLASS command connects strategies and operators to OPERATOR 1. <# means that strategy 1 will use the <# operator. Finally, the the _same function is connected with the operator class.

Note that the operator class has a name, and that it has been explicitly defined to work with B-trees. The operator class can already be used during index creation:

CREATE INDEX idx_special ON t_sva (sva sva_special_ops);

Creating an index works in a slightly different way than before: sva sva_special_ops means that the sva column is indexed using the sva_special_ops operator class. If sva_special_ops is not explicitly used, then PostgreSQL will not go for our special sort order, and will instead decide on the default operator class.