Accessing the Database

Chap Core stores its data in a PostgreSQL database that runs as the postgres service in Docker Compose. The database port is not published to the host, so you connect to it through the running postgres container rather than from your host machine.

The database credentials come from your .env file: POSTGRES_USER (default chap), POSTGRES_PASSWORD (default chap), and POSTGRES_DB (default chap_core).

Open a psql shell

To open an interactive psql session:

docker compose exec postgres sh -c 'psql -U "$POSTGRES_USER" -d "$POSTGRES_DB"'

Running it as sh -c '...' lets psql read the credentials from the container's own environment, so it works regardless of what you set in .env. From the prompt you can list the tables with \dt, run SQL queries, and type \q to exit.

Run a one-off command

To run a single command without opening an interactive session, pass it with -c. For example, to list the tables:

docker compose exec postgres sh -c 'psql -U "$POSTGRES_USER" -d "$POSTGRES_DB" -c "\dt"'

The same works for SQL queries, for example:

docker compose exec postgres sh -c 'psql -U "$POSTGRES_USER" -d "$POSTGRES_DB" -c "SELECT COUNT(*) FROM dataset;"'

Backing up and restoring

For creating and restoring database backups with pg_dump, see Backup Your Database in the upgrade guide.