How to make (patient id) forgein key in table of bill? - sql

Question

I try to create three tables by using website suport compiler any code but I have a problem in the table of the bill.
When I run it I get to error show me it is near in foreign key
These are codes of three tables
CREATE TABLE patient (
Patient Id (5) Primary key,
Name Varchar (20) Not null ,
Age Int Not null ,
Weight Int Not null ,
Gender Varchar (10) Not null,
Address Varchar (50) Not null ,
Disease Varchar (20) Not null
);
CREATE TABLE doctors (
DoctorId Varchar (5) Primary key,
Doctorname Varchar (15) Not null,
Dept Varchar (15) Not null
);
CREATE TABLE bill (
Bill_no Varchar (50) Primary key,
Patient_Id Varchar (5) Foreign key,,
doctor_charge Int Not null,
patient_type Varchar (10) null,
no_of_days Int null,
lab_charge Int null,
bill Int Not null
);

Answer 1

Patient Table
CREATE TABLE patient
(
patient_id VARCHAR (5) PRIMARY KEY,
name VARCHAR (20) NOT NULL,
age INT NOT NULL,
weight INT NOT NULL,
gender VARCHAR (10) NOT NULL,
address VARCHAR (50) NOT NULL,
disease VARCHAR (20) NOT NULL
);
Errors
No data type has been assigned in Patient id column (Patient Id (5)
Primary key)
Patient id column name contains spaces. You need to
enclose the column name in double quotes or replace space with something else
(ex: _). It's not recommended to use spaces.
A column name with space
CREATE TABLE tablename ("column name" datatype);
Doctors Table
CREATE TABLE doctors
(
doctorid VARCHAR (5) PRIMARY KEY,
doctorname VARCHAR (15) NOT NULL,
dept VARCHAR (15) NOT NULL
);
Bill Table
CREATE TABLE bill
(
bill_no VARCHAR (50) PRIMARY KEY,
patient_id VARCHAR (5),
doctor_charge INT NOT NULL,
patient_type VARCHAR (10) NULL,
no_of_days INT NULL,
lab_charge INT NULL,
bill INT NOT NULL,
FOREIGN KEY (patient_id) REFERENCES patient(patient_id)
);
Errors
The way you have assigned foreign key is wrong. Please refer this and this article for more information. (Patient_Id Varchar (5) Foreign key,,)
There are two commans in the Patient_Id column (Patient_Id Varchar (5) Foreign key,,)

Answer 2

You have to provide reference of the table for which you want to use the reference key.
For example, you have table Persons which has Primary key PersonID, in that case if you want to use that as foreign key in another table, lets say Orders.
In Oracle
CREATE TABLE Orders (
OrderID numeric(10) not null,
OrderNumber numeric(10) not null,
PersonID numeric(10) not null,
CONSTRAINT fk_person_id
FOREIGN KEY (PersonID )
REFERENCES Persons(PersonID )
Your Case :
CREATE TABLE bill
( Bill_no Varchar (50) Primary key,
Patient_Id Varchar (5),
doctor_charge Int Not null,
patient_type Varchar (10) null,
no_of_days Int null,
lab_charge Int null,
bill Int Not null,
CONSTRAINT fk_patient_id
FOREIGN KEY (Patient_Id)
REFERENCES patient(Patient_Id)
);

Answer 3

Remove the 'Foreign Key' from the table creation script.
Add this to your SQL script:
ALTER TABLE [Bill] WITH CHECK ADD CONSTRAINT [FK_Bill_Patient] FOREIGN KEY([Patient_Id])
REFERENCES [Patient] ([Patient_Id])
GO
ALTER TABLE [Bill] CHECK CONSTRAINT [FK_Bill_Patient]
GO

Answer 4

The words FOREIGN KEY are only needed for introducing the name of the FK constraint. Since your other constraints are not named, you might as well skip that part and go straight to REFERENCES.
If you specify a foreign key constraint as part of the column definition, you can omit the datatype to allow it to inherit from its parent at the time of creation, which I think is good practice as the types will automatically match.
We use VARCHAR2 in Oracle, not VARCHAR.
You don't need to specify NULL for columns that are allowed to be null.
I am not sure a 5-character string is a good datatype for a unique ID. How will you generate the values? Normally an auto-incrementing sequence number simplifies this.
create table doctors
( doctorid varchar2(5) primary key
, doctorname varchar2(15) not null
, dept varchar2(15) not null );
create table patients
( patient_id varchar2(5) primary key
, name varchar2(20) not null
, age integer not null
, weight integer not null
, gender varchar2(10) not null
, address varchar2(50) not null
, disease varchar2(20) not null );
create table bills
( bill_no varchar2(50) primary key
, patient_id references patients -- Allow datatype to inherit from parent
, patient_type varchar2(10)
, no_of_days integer
, lab_charge integer
, bill integer not null );