How to connect to local's database from docker containers using docker-compose?

Question

I'm working on Spring-boot app I want it to connect to the local's database from the insider docker containers. I'm using Ubuntu 18 and 1.28 for docker-compose. I have found several solutions but no luck on me,

Below are the solutions I've found on the Stackoverflow but it's not working,

1. network_mode: "host"

:

version: "3"

services:

  partner:
    container_name: customer
    image: cms/customer-service
    build:
      context: cms-customer-service/
    ports:
      - "8003:8000"
    restart: always
    network_mode: "host" 
    networks:
      - api_network      

networks:
  api_network:
    driver: bridge

This solution throws the error

'ERROR: 'network_mode' and 'networks' cannot be combined'

But If I remove the networks, how can the Docker Containers connect to each other ? Then I removed the "networks:" part, so I got this error

docker.errors.InvalidArgument: "host" network_mode is incompatible with port_bindings

2. host.docker.internal

I got "Connection to host.docker.internal:5432 refused" If I used host.docker.internal instead of localhost.

Please help.