Getting Class "mysqli" not found when using docker container to load mysql and php

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First time working with creating a docker container, i am trying to add a mysql container which seems to be added fine according to the command line however in the browser i get error class mysqli not found

I have added a docker file which includes the following Dockerfile

FROM php:8.0-apache
RUN docker-php-ext-install mysqli && docker-php-ext-enable mysqli
RUN apt-get update && apt-get upgrade -y

docker-compose.yml

version: '3.6'
services:
  php-apache-environment:
    container_name: php-apache
    image: php:8.0-apache 
    volumes:
      - ./php/src:/var/www/html/
    ports:
      - 8000:80
  db:
    container_name: db
    image: mysql
    restart: always
    environment:
        MYSQL_ROOT_PASSWORD: MYSQL_ROOT_PASSWORD
        MYSQL_DATABASE: MY_DATABASE
        MYSQL_USER: MYSQL_USER
        MYSQL_PASSWORD: MYSQL_PASSWORD
    ports:
        - "9906:3306"

I have also ran docker compose up However i am still getting error class mysqli not found