clinical_app

 Prompt#1 :

Create a database called clinicals and use it.

Create tables with normalized design to properly capture patient and his clinical data and join them using patient key .

Insert sample data for 5 patients with 2 sample data each.

show databases;

drop database clinicals;

SHOW TABLES;


-- Create the database

CREATE DATABASE clinicals;


-- Use the database

USE clinicals;


-- Create Patients table

CREATE TABLE patient (

    id INT NOT NULL AUTO_INCREMENT,

    first_name VARCHAR(255) NOT NULL,

    last_name VARCHAR(255) NOT NULL,

    age INT,

    PRIMARY KEY (id)

);


-- Create Clinical Data table (joined to patient)

CREATE TABLE clinical_data (

    id INT NOT NULL AUTO_INCREMENT,

    patient_id INT NOT NULL,

    component_name VARCHAR(255) NOT NULL,

    component_value VARCHAR(255) NOT NULL,

    measured_date_time TIMESTAMP,

    PRIMARY KEY (id),

    FOREIGN KEY (patient_id) REFERENCES patient(id)

);


-- Insert sample patients

INSERT INTO patient (first_name, last_name, age) VALUES

('John', 'Doe', 52),

('Jane', 'Smith', 32),

('Alice', 'Johnson', 22),

('Bob', 'Williams', 33),

('Emily', 'Brown', 55);


-- Insert sample clinical data (2 records per patient)

INSERT INTO clinical_data (patient_id, component_name, component_value, measured_date_time) VALUES

(1, 'bp', '120/80', '2025-08-01 10:00:00'),

(1, 'heartrate', '72', '2025-08-01 10:05:00'),

(2, 'bp', '130/85', '2025-08-02 11:00:00'),

(2, 'heartrate', '75', '2025-08-02 11:05:00'),

(3, 'bp', '110/70', '2025-08-03 12:00:00'),

(3, 'heartrate', '68', '2025-08-03 12:05:00'),

(4, 'bp', '125/82', '2025-08-04 13:00:00'),

(4, 'heartrate', '80', '2025-08-04 13:05:00'),

(5, 'bp', '118/78', '2025-08-05 14:00:00'),

(5, 'heartrate', '70', '2025-08-05 14:05:00');



Check:


select first_name, last_name, age, component_name, component_value, measured_date_time from patient p , clinical_data d where p.id = d.patient_id;



drop table patient;

drop table clinical_data;

drop database clinic;

__________________________________________________________________________________________________________________________________


prompt#2: Open the command pallete


@vscode create java project


VCC > Java project > Spring boot > maven project >


spring web

spring jpa

mysql driver

package name : com.clinic

rest_app

create a folders

1. model

2. repos

3. Dto

4. Controllers

5. resources

__________________________________________________________________________________________________________________________________


JPA can be defined as Java Persistence API


Creating the JPA Models :


Prompt#3: 

Create a JPA model class for the below table

TABLE patient (

    id INT NOT NULL AUTO_INCREMENT,

    first_name VARCHAR(255) NOT NULL,

    last_name VARCHAR(255) NOT NULL,

    age INT,

    PRIMARY KEY (id)

);


Check for the below:


    1) Packages  - import jakarta.persistence.*;

    2) Annotations - @Entity, @Table @OneToMany, @JoinColumn

    @OneToMany(mappedBy = "patient", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)

    3) getters and setters for every datatypes and objects


import jakarta.persistence.*;


@Entity

@Table(name = "patient")

public class Patient {

    @Id

    @GeneratedValue(strategy = GenerationType.IDENTITY)



Prompt#4: 

Create a JPA model class for the below table with ManyToOne and JsonIgnore annotations


TABLE clinical_data (

    id INT NOT NULL AUTO_INCREMENT,

    patient_id INT NOT NULL,

    component_name VARCHAR(255) NOT NULL,

    component_value VARCHAR(255) NOT NULL,

    measured_date_time TIMESTAMP,

    PRIMARY KEY (id),

    FOREIGN KEY (patient_id) REFERENCES patient(id)

);


Check for the below:


    1) Packages  - import jakarta.persistence.*;

    2) Annotations - @Entity, @Table, @ManyToOne, @JoinColumn, @JsonIgnore, @CreationTimestamp

    3) getters and setters for every datatypes and objects


    @Entity

    @Table(name = "clinical_data")

    public class ClinicalData {

        @Id

        @GeneratedValue(strategy = GenerationType.IDENTITY)

        private Integer id;


        @ManyToOne

        @JoinColumn(name = "patient_id", nullable = false)


    change the package to import java.sql.Timestamp;



Check the ManyToOne and OneToMany dependancies in JPA.


_____________________________________________________________________________________________


Create the JPA Model Repositories:


Create the JPA Model Repository for the JPA Model Patient.java in repos folder

Create the JPA Model Repository for the JPA Model ClinicalData.java in repos folder


Check:

1. import the model java 

2. @Repository

3. interface ClinicalDataRepository extends JpaRepository

_____________________________________________________________________________________________


Create Dto:


Create a PatientDataRequest java file  

Create a ClinicalDataRequest java file


Checks:

    1. patient id should be integer

    2. getters and setters

_____________________________________________________________________________________________


Rest Controllers


Prompt: 

Create a Rest controller that uses PatienetRepository.java and exposes a rest api to perform CRUD operations



Checks:

import section 


model class

repo class 


Annotations:

@RestController

@RequestMapping("/api/patients")

@CrossOrigin(origins = "*")


CRUD operations


Prompt: 

Create a Rest controller that uses ClinicalDataRepository.java and exposes a rest api to perform CRUD operations


import section 


model class

Annotations:

@RestController

@RequestMapping("/api/patients")

@CrossOrigin(origins = "*")

@annotate repo classes 

CRUD operations

Add a save method uses ClinicalDataRequest object as parameter to save clinical data


_____________________________________________________________________________________________


Configure Data Source and properties


spring.application.name=clinicals_rest_app

spring.datasource.url=jdbc:mysql://localhost:3306/clinic

spring.datasource.username=root

spring.datasource.password=MysqlAdmin@123

spring.jpa.hibernate.ddl-auto=update

spring.jpa.show-sql=true


server.servlet.context-path=/clinicalservices


_____________________________________________________________________________________________


Main SpringBootApplication:


@SpringBootApplication

public class ClinicalsDemoApplication {


Run the stand alone application using Postman.


Pre - Checks:

Package structure - main class package is base . controller , model, repos packages are subpackages


Run the 

ClinicalsDemoApplication.java 


Logs check:

 Tomcat started on port 8080 (http) with context path '/clinicalservices'


 port is ok

 context path is ok


Test using postman or browser:

 

http://localhost:8080/clinicalservices/api/patients

 

http://localhost:8080/clinicalservices/api/patients/4


http://localhost:8080/clinicalservices/api/clinicaldata


_____________________________________________________________________________________________


Possible errors:

Helper   : SQL Error: 1045, SQLState: 28000

2025-08-21T09:21:38.550+08:00 ERROR 2528 --- [clinicals_rest_app] [           main] o.h.engine.jdbc.spi.SqlExceptionHelper   : Access denied for user 'root'@'localhost' (using password: YES)

2025-08-21T09:21:38.552+08:00  WARN 2528 --- [clinicals_rest_app] [           main] o.h.e.j.e.i.JdbcEnvironmentInitiator     : HHH000342: Could not obtain connection to query metadata


org.hibernate.exception.GenericJDBCException: unable to obtain isolated JDBC connection [Access denied for user 'root'@'localhost' (using password: YES)] [n/a]

        at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:63) ~[hibernate-core-6.6.22.Final.jar:6.6.22.Final]

        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:108) ~[hibernate-core-6.6.22.Final.jar:6.6.22.Final]

        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:94) ~[hibernate-core-6.6.22.Fi


_____________________________________________________________________________________________


Create a React project


1. npx create-react-app@latest clinicals-webapp

2. npm install react-router-dom

3. npm install axios

4. npm install react-toastify


cd clinicals-app

npm start



Open the clinicals-app in Code editor


create a component folder 

Create a place holder files

Home.js

Patient.js

Clinical.js

export default function Home (){

return (

<b> Home </b>

);

}



App.js


1. Create a Header with light background and minimum height 10vh

2. Create a <NAV> and nav list with background , flex type , list style none , horizontal menu type, left sided

3. Add Routing details

<BrowseRouter>

<Routes>

<Route>

<Route>

<Route>

</Routes>

</BrowseRouter>

4. Create a Footer 

5. Add ToastContainer


_________________________________________________________________________________________________________________________________


Impement Home.js


Prompt : react component that makes a api call using axios to fetch the patient details and then renders them as html table.


check the Name  Home

Check the constants patients and set patients

fetch() - set the path  axios.get ('http://localhost:8080/patientservices/patients')

useeffect as soon as mounted ( [] )

rendering - return statement


CORS issue - (No access is allowed for cross origint request )

__________________________________________________________________________________________________________________________________


CORS Error fix in Spring boot


Add the annotation 

@CrossOrigin(origins="*")


__________________________________________________________________________________________________________________________________


Add Patient.js


prompt : Create a React component that gathers patinet information like first name, last name , age and makes axios api call to save the patient object.


check the name

check the constatnts for each field

check the functions to set the values

check the handle submit function

check the axios api call

__________________________________________________________________________________________________________________________________


React Toastify 


<ToastContainer autoClose={2000}/>

import { toast} from 'react-toastify'


__________________________________________________________________________________________________________________________________


Add Clinical Data - Part 1


Prompt: Retrieve the patient details for a given Patient Id and render the details in table.


Check the name 

Check the constatnts - parent

Check the param - 


Add Clinical Data - Part 2


Prompt: Gather the component name , value using html forms and make an api call using axios to save the data.


submit function - axios fetch


__________________________________________________________________________________________________________________________________

Add Back links 


__________________________________________________________________________________________________________________________________


Styling 


___________________________________________________________________________________


Datasource:


Possible errors:


    Helper   : SQL Error: 1045, SQLState: 28000

    2025-08-21T09:21:38.550+08:00 ERROR 2528 --- [clinicals_rest_app] [           main] o.h.engine.jdbc.spi.SqlExceptionHelper   : Access denied for user 'root'@'localhost' (using password: YES)

    2025-08-21T09:21:38.552+08:00  WARN 2528 --- [clinicals_rest_app] [           main] o.h.e.j.e.i.JdbcEnvironmentInitiator     : HHH000342: Could not obtain connection to query metadata


    org.hibernate.exception.GenericJDBCException: unable to obtain isolated JDBC connection [Access denied for user 'root'@'localhost' (using password: YES)] [n/a]

            at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:63) ~[hibernate-core-6.6.22.Final.jar:6.6.22.Final]

            at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:108) ~[hibernate-core-6.6.22.Final.jar:6.6.22.Final]

            at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:94) ~[hibernate-core-6.6.22.Fi


Fix:


spring.datasource.url=jdbc:mysql://localhost:3306/clinic - clinic is a database name

spring.datasource.username=root

spring.datasource.password=MysqlAdmin@123 - correct password


_____________________________________________________________________________________________


Controller is not working:


Check the application logs for the full stack trace of the error. It will show the exact cause.


Make sure all clinical_data rows in your database have valid patient_id values that exist in the patient table.


Ensure your ClinicalData entity uses the correct type for the measuredDateTime field (e.g., Timestamp or LocalDateTime) and matches the database column type.


If you have circular references (e.g., Patient has a list of ClinicalData and vice versa), use @JsonIgnore or @JsonManagedReference/@JsonBackReference to avoid infinite recursion in JSON serialization.




_____________________________________________________________________________________________

This error is caused by Jackson (JSON serialization) trying to serialize a Hibernate proxy object, usually due to lazy loading and bidirectional relationships.


How to fix:


Add @JsonIgnore to the patient field in ClinicalData:

@ManyToOne

@JoinColumn(name = "patient_id", nullable = false)

@JsonIgnore

private Patient patient;




Or, use @JsonManagedReference and @JsonBackReference for bidirectional relationships:


    On the patient field in ClinicalData:


    @ManyToOne

    @JoinColumn(name = "patient_id", nullable = false)

    @JsonBackReference

    private Patient patient;




    On the list of clinical data in Patient (if present):


    @OneToMany(mappedBy = "patient")

    @JsonManagedReference

    private List<ClinicalData> clinicalDataList;

___________________________________________________________________________________


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