Variables passed to the PL/pgSQL TRIGGER function

The following is a complete list of variables available to a trigger function written in PL/pgSQL:

OLD, NEW	RECORD	before and after images of the row the trigger is called on. OLD is unassigned for INSERT and NEW is unassigned for DELETE. Both are UNASSIGNED in statement-level triggers.
TG_NAME	name	The name of the trigger (this and following from the trigger definition).
TG_WHEN	text	One of BEFORE, AFTER, or INSTEAD OF.
TG_LEVEL	text	ROW or STATEMENT.
TG_OP	text	One of INSERT, UPDATE, DELETE, or TRUNCATE.
TG_RELID	oid	OID of the table the trigger is created on.
TG_TABLE_NAME	name	The name of the table (old spelling TG_RELNAME is deprecated but still available).
TG_TABLE_SCHEMA	name	The schema name of the table.
TG_NARGS, TG_ARGV[]	Int, text[]	Number of arguments and the array of the arguments from trigger definition.