pg_cast

The pg_cast table stores data type conversion paths, both built-in paths and those defined with CREATE CAST.

Column Type References Description

Column	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. `0` is stored if the cast method does not require a function
castcontext	char	—	Indicates what contexts the cast may be invoked in: `e` means only as an explicit cast (using `CAST` or `::` syntax). `a` means implicitly in assignment to a target column, as well as explicitly. `i` means implicitly in expressions, as well as the other cases.
castmethod	char	—	Indicates how the cast is performed: `f` — the function identified in the `castfunc` field is used. `i` — the input/output functions are used. `b` — the types are binary-coercible, and no conversion is required.

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. 0 is stored if the cast method does not require a function

castcontext

char

—

Indicates what contexts the cast may be invoked in:

castmethod

char

—

Indicates how the cast is performed: