The catalog pg_opclass defines index access method operator classes. Each operator class defines semantics for index columns of a particular data type and a particular index access method. An operator class essentially specifies that a particular operator family is applicable to a particular indexable column data type. The set of operators from the family that are actually usable with the indexed column are whichever ones accept the column's data type as their left-hand input.
Operator classes are described at length in Section 35.14.
Table 45-31. pg_opclass Columns
|opcmethod||oid||pg_am.oid||Index access method operator class is for|
|opcname||name||Name of this operator class|
|opcnamespace||oid||pg_namespace.oid||Namespace of this operator class|
|opcowner||oid||pg_authid.oid||Owner of the operator class|
|opcfamily||oid||pg_opfamily.oid||Operator family containing the operator class|
|opcintype||oid||pg_type.oid||Data type that the operator class indexes|
|opcdefault||bool||True if this operator class is the default for opcintype|
|opckeytype||oid||pg_type.oid||Type of data stored in index, or zero if same as opcintype|
An operator class's opcmethod must match the opfmethod of its containing operator family. Also, there must be no more than one pg_opclass row having opcdefault true for any given combination of opcmethod and opcintype.
Please use this form to add your own comments regarding your experience with particular features of PostgreSQL, clarifications of the documentation, or hints for other users. Please note, this is not a support forum, and your IP address will be logged. If you have a question or need help, please see the faq, try a mailing list, or join us on IRC. Note that submissions containing URLs or other keywords commonly found in 'spam' comments may be silently discarded. Please contact the webmaster if you think this is happening to you in error.
Proceed to the comment form.