Question

Using the table below, Write 2 simple/short TRIGGER STATEMENTS (WITH GOOD BUSINESS VALUE),

After writing the trigger statements, please comment on what the TRIGGER IS DOING.

CREATE TABLE STUDENT_TBL
(
STU_ID       NUMBER (8) NULL,
F_NAME       VARCHAR (20) NULL,  
L_NAME       VARCHAR (30) NULL,  
STU_MAJOR       VARCHAR (20) NULL,  
STU_ADDR        VARCHAR (50) NULL,
STU_EMAIL       VARCHAR (30) NULL,
CONSTRAINT PKSTU primary key (STU_ID)
);
DESCRIBE STUDENT_TBL;

CREATE TABLE ENROLL_TBL
(
ENR_ID   NUMBER (8),
ENR_DATE     DATE (10) NULL,  
ENR_LOCATION        VARCHAR (10) NULL,
ENR_GRADE    VARCHAR (10) NULL,
CL_ID     VARCHAR (10) NULL,
CONSTRAINT PKENR    primary key (ENR_ID),

);
DESCRIBE ENROLL_TBL;

CREATE TABLE CLASS_TBL
(
CL_ID NUMBER (8),
CL_SECTION     VARCHAR (10) NULL,  
CL_TIME    VARCHAR (18) NULL,  
ROOM_CAPACITY    VARCHAR (10) NULL,  
PROFESSOR_ID    VARCHAR (10) NULL,  
CONSTRAINT PKCL       primary key (CL_ID),
CONSTRAINT FKPROF     foreign key (PROF_ID) references PROFESSOR,
CONSTRAINT FKRMCAPACITY     foreign key (ROOM_CAPACITY) references ROOM

);

DESCRIBE CLASS_TBL;

CREATE TABLE COURSE_TBL
(
CRS_ID    NUMBER (8),
CRS_DESCRIPTION   VARCHAR (20) NULL,  
CRS_NAME       VARCHAR (20) NULL,  
CRS_CREDIT       VARCHAR (5) NULL,  
CRS_LOCATION       VARCHAR (10) NULL,
CONSTRAINT PKCRS     primary key (CRS_ID)
);
DESCRIBE COURSE_TBL;

CREATE TABLE PROFESSOR_TBL
(
PROF_ID       NUMBER,
PROF_FNAME       VARCHAR (10) NULL,  
PROF_LNAME      VARCHAR (20) NULL,  
PROF_EMAIL       VARCHAR (30) NULL,
PROF_DEPT       VARCHAR (20) NULL,
PROF_PHONE        VARCHAR (18) NULL,
CONSTRAINT PKPROF     primary key (PROF_ID)
);
DESCRIBE PROFESSOR_TBL;

CREATE TABLE ROOM_TBL
(
RM_ID           NUMBER,
RM_NAME       VARCHAR (10) NULL,  
RM_TYPE       VARCHAR (20) NULL,  
RM_TIME       VARCHAR (18) NULL,
RM_CAPACITY   VARCHAR (10) NULL,
CONSTRAINT PKRM     primary key (RM_ID)
);