Temporary tables are similar like an ordinary tables have contains all the attributes of a table including information about rows and block, triggers, join cardinality, etc. .
temporary tables can't foreign keys related to other tables.
CREATE GLOBAL TEMPORARY TABLE tablename( columnname datatype [ NULL | NOT NULL ]);
CREATE GLOBAL TEMPORARY TABLE students (student_id numeric(11) NOT NULL, student_name varchar2(50) NOT NULL,student_city varchar2(50) );