43.8. pg_cast

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

Table 43-8. pg_cast Columns

NameTypeReferencesDescription
castsourceoidpg_type.oidOID of the source data type
casttargetoidpg_type.oidOID of the target data type
castfuncoidpg_proc.oid The OID of the function to use to perform this cast. Zero is stored if the data types are binary compatible (that is, no run-time operation is needed to perform the cast).
castcontextchar  Indicates what contexts the cast may be invoked in. e means only as an explicit cast (using CAST, ::, or function-call 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.
the column is an array type; otherwise 0.