CREATE TABLE "JOB_HISTORY" 
   (	"EMPLOYEE_ID" NUMBER(6,0) CONSTRAINT "JHIST_EMPLOYEE_NN" NOT NULL ENABLE, 
	"START_DATE" DATE CONSTRAINT "JHIST_START_DATE_NN" NOT NULL ENABLE, 
	"END_DATE" DATE CONSTRAINT "JHIST_END_DATE_NN" NOT NULL ENABLE, 
	"JOB_ID" VARCHAR2(10) CONSTRAINT "JHIST_JOB_NN" NOT NULL ENABLE, 
	"DEPARTMENT_ID" NUMBER(4,0), 
	 CONSTRAINT "JHIST_DATE_INTERVAL" CHECK (end_date > start_date) ENABLE, 
	 CONSTRAINT "JHIST_JOB_FK" FOREIGN KEY ("JOB_ID")
	  REFERENCES "JOBS" ("JOB_ID") ENABLE, 
	 CONSTRAINT "JHIST_EMP_FK" FOREIGN KEY ("EMPLOYEE_ID")
	  REFERENCES "EMPLOYEES" ("EMPLOYEE_ID") ENABLE, 
	 CONSTRAINT "JHIST_DEPT_FK" FOREIGN KEY ("DEPARTMENT_ID")
	  REFERENCES "DEPARTMENTS" ("DEPARTMENT_ID") ENABLE
   ) ;
  CREATE UNIQUE INDEX "JHIST_EMP_ID_ST_DATE_PK" ON "JOB_HISTORY" ("EMPLOYEE_ID", "START_DATE") 
  ;
ALTER TABLE "JOB_HISTORY" ADD CONSTRAINT "JHIST_EMP_ID_ST_DATE_PK" PRIMARY KEY ("EMPLOYEE_ID", "START_DATE")
  USING INDEX "JHIST_EMP_ID_ST_DATE_PK"  ENABLE;