How to *Count the number of Dr who are visiting 'KEM" hospital in Many to Many Relationship
I have created 3 Tables
Doctor dno PRIMARY KEY
Hospital dno PRIMARY KEY
Dochos dno REFERENCES Doctor
hno REFERENCES Hospital
CREATE TABLE Doctor (
dno NUMBER(7) PRIMARY KEY,
dname VARCHAR2(33),
city VARCHAR2(33) not null);
INSERT INTO Doctor VALUES (&dno, &dname, &City);
[CODEE]CREATE TABLE Hospital (
hno NUMBER(7) PRIMARY KEY,
hname VARCHAR2(20),
hcity VARCHAR2(20) not null);
INSERT INTO Hospital VALUES (&hno, &hame, &hcity);
CREATE TABLE Dochos (
dno NUMBER(7) REFERENCES Doctor,
hno NUMBER(7) REFERENCES Hospital);
INSERT INTO Dochos VALUES (&dno, &hno);
SQL> SELECT * FROM Doctor;
DNO DNAME CITY
---------- --------------------------------- ----------------------
1 Sharma Pune
2 Varma Pune
3 Swami Delhi
4 Rashmi Mumbai
QL> SELECT * FROM Hospital;
HNO HNAME HCITY
--------- -------------------- --------------------
1 Sasoon Pune
2 Jehagir Mumbai
3 Rakshak Clinic Delhi
4 Budani Pune
5 KEM Patna
SQL> SELECT * FROM Dochos;
DNO HNO
---------- ----------
1 1
2 2
3 3
4 4[/CODE]
I have created 3 Tables
Doctor dno PRIMARY KEY
Hospital dno PRIMARY KEY
Dochos dno REFERENCES Doctor
hno REFERENCES Hospital
CREATE TABLE Doctor (
dno NUMBER(7) PRIMARY KEY,
dname VARCHAR2(33),
city VARCHAR2(33) not null);
INSERT INTO Doctor VALUES (&dno, &dname, &City);
[CODEE]CREATE TABLE Hospital (
hno NUMBER(7) PRIMARY KEY,
hname VARCHAR2(20),
hcity VARCHAR2(20) not null);
INSERT INTO Hospital VALUES (&hno, &hame, &hcity);
CREATE TABLE Dochos (
dno NUMBER(7) REFERENCES Doctor,
hno NUMBER(7) REFERENCES Hospital);
INSERT INTO Dochos VALUES (&dno, &hno);
SQL> SELECT * FROM Doctor;
DNO DNAME CITY
---------- --------------------------------- ----------------------
1 Sharma Pune
2 Varma Pune
3 Swami Delhi
4 Rashmi Mumbai
QL> SELECT * FROM Hospital;
HNO HNAME HCITY
--------- -------------------- --------------------
1 Sasoon Pune
2 Jehagir Mumbai
3 Rakshak Clinic Delhi
4 Budani Pune
5 KEM Patna
SQL> SELECT * FROM Dochos;
DNO HNO
---------- ----------
1 1
2 2
3 3
4 4[/CODE]