PG_OPCLASS
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 data types that accept the left-hand column.
Name |
Type |
Reference |
Description |
---|---|---|---|
oid |
oid |
- |
Row identifier (hidden attribute, which must be specified) |
opcmethod |
oid |
PG_AM.oid |
Index access method operator class served by an operator class |
opcname |
name |
- |
Name of the operator class |
opcnamespace |
oid |
PG_NAMESPACE.oid |
Namespace of the 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 |
boolean |
- |
The value is t (true) if the operator class is the default for opcintype. Otherwise, the value is f (false). |
opckeytype |
oid |
PG_TYPE.oid |
Type of data stored in an index, or zero if same as opcintype |
An operator class's opcmethod must match the opfmethod of its containing operator family.
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