pg_cast stores data type conversion paths defined with CREATE CAST plus the built-in conversions.
Table 3-8. pg_cast Columns
| Name | Type | References | Description |
|---|---|---|---|
| castsource | oid | pg_type.oid | OID of the source data type |
| casttarget | oid | pg_type.oid | OID of the target data type |
| castfunc | oid | pg_proc.oid | The OID of the function to use to perform this cast. A 0 is stored if the data types are binary compatible (that is, no function is needed to perform the cast). |
| castimplicit | bool | Indication whether this cast can be invoked implicitly |