PG_CAST

PG_CAST records conversion relationships between data types.

**Table 1** PG_CAST columns
Column	Type	Description
castsource	oid	OID of the source data type.
casttarget	oid	OID of the target data type.
castfunc	oid	OID of the conversion function. If the value is 0, no conversion function is required.
castcontext	"char"	Conversion mode between the source and target data types e: indicates that only explicit conversion can be performed (using the CAST or :: syntax). i: indicates that only implicit conversion can be performed. a: indicates that both explicit and implicit conversion can be performed between data types.
castmethod	"char"	Conversion method f: indicates that conversion is performed using the specified function in the castfunc column. b: indicates that binary forcible conversion rather than the specified function in the castfunc column is performed between data types.