DROP FOREIGN DATA WRAPPER — remove a foreign-data wrapper
DROP FOREIGN DATA WRAPPER [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]
   DROP FOREIGN DATA WRAPPER removes an existing
   foreign-data wrapper.  To execute this command, the current user
   must be the owner of the foreign-data wrapper.
  
IF EXISTSDo not throw an error if the foreign-data wrapper does not exist. A notice is issued in this case.
nameThe name of an existing foreign-data wrapper.
CASCADEAutomatically drop objects that depend on the foreign-data wrapper (such as foreign tables and servers), and in turn all objects that depend on those objects (see Section 5.13).
RESTRICTRefuse to drop the foreign-data wrapper if any objects depend on it. This is the default.
   Drop the foreign-data wrapper dbi:
DROP FOREIGN DATA WRAPPER dbi;
   DROP FOREIGN DATA WRAPPER conforms to ISO/IEC
   9075-9 (SQL/MED).  The IF EXISTS clause is
   a PostgreSQL extension.