Named Volume — State 의 옳은 디폴트

# Create explicitly (optional — auto-created on first use)
docker volume create pgdata

# List
docker volume ls

# Inspect (where it lives, options, labels)
docker volume inspect pgdata

# Remove (only when no container uses it)
docker volume rm pgdata

# Remove all unused volumes (ASK YOURSELF FIRST)
docker volume prune

# First container
docker run -d --name db \
  -v pgdata:/var/lib/postgresql/data \
  -e POSTGRES_PASSWORD=secret \
  postgres:16

# Insert data
docker exec -it db psql -U postgres -c "CREATE TABLE t(x int); INSERT INTO t VALUES(7);"

# Tear down completely
docker rm -f db

# Recreate
docker run -d --name db \
  -v pgdata:/var/lib/postgresql/data \
  -e POSTGRES_PASSWORD=secret \
  postgres:16

# Verify
docker exec -it db psql -U postgres -c "SELECT * FROM t;"
# x | 7  ← still there