diff --git a/scripts/enterdb.sh b/scripts/enterdb.sh
new file mode 100644
index 0000000..32ffa94
--- /dev/null
+++ b/scripts/enterdb.sh
@@ -0,0 +1,83 @@
+#!/usr/bin/env sh
+set -eu
+
+SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
+PROJECT_DIR=$(dirname -- "$SCRIPT_DIR")
+cd "$PROJECT_DIR"
+
+fatal() {
+    printf 'enterdb: %s\n' "$*" >&2
+    exit 1
+}
+
+command -v docker >/dev/null 2>&1 || fatal "docker is not available in PATH"
+docker compose version >/dev/null 2>&1 || fatal "docker compose is not available"
+
+service_running() {
+    docker compose ps --status running --services 2>/dev/null | grep -Fxq "$1"
+}
+
+# DATABASE_URL from the running application is the source of truth for the selected database engine.
+DATABASE_URL_VALUE=""
+if service_running app; then
+    DATABASE_URL_VALUE=$(docker compose exec -T app sh -c 'printf "%s" "${DATABASE_URL:-}"' 2>/dev/null || true)
+fi
+
+case "$DATABASE_URL_VALUE" in
+    postgres://*|postgresql://*)
+        DATABASE_ENGINE=postgres
+        ;;
+    mysql://*)
+        DATABASE_ENGINE=mysql
+        ;;
+    sqlite://*)
+        fatal "the application uses SQLite; this script supports PostgreSQL and MySQL"
+        ;;
+    "")
+        POSTGRES_RUNNING=false
+        MYSQL_RUNNING=false
+        service_running postgres && POSTGRES_RUNNING=true
+        service_running mysql && MYSQL_RUNNING=true
+
+        if [ "$POSTGRES_RUNNING" = true ] && [ "$MYSQL_RUNNING" = false ]; then
+            DATABASE_ENGINE=postgres
+        elif [ "$MYSQL_RUNNING" = true ] && [ "$POSTGRES_RUNNING" = false ]; then
+            DATABASE_ENGINE=mysql
+        elif [ "$POSTGRES_RUNNING" = true ] && [ "$MYSQL_RUNNING" = true ]; then
+            fatal "PostgreSQL and MySQL are both running, and DATABASE_URL could not be read from the app service"
+        else
+            fatal "no running postgres or mysql service was found"
+        fi
+        ;;
+    *)
+        fatal "unsupported DATABASE_URL: $DATABASE_URL_VALUE"
+        ;;
+esac
+
+case "$DATABASE_ENGINE" in
+    postgres)
+        service_running postgres || fatal "the postgres service is not running"
+        printf 'Connecting to PostgreSQL...\n' >&2
+        exec docker compose exec postgres sh -lc '
+            export PGPASSWORD="${POSTGRES_PASSWORD:-rustpad}"
+            exec psql --host=127.0.0.1 --username="${POSTGRES_USER:-rustpad}" --dbname="${POSTGRES_DB:-rustpad}"
+        '
+        ;;
+    mysql)
+        service_running mysql || fatal "the mysql service is not running"
+        printf 'Connecting to MySQL...\n' >&2
+        exec docker compose exec mysql sh -lc '
+            if command -v mysql >/dev/null 2>&1; then
+                client=mysql
+            elif command -v mariadb >/dev/null 2>&1; then
+                client=mariadb
+            else
+                echo "enterdb: no mysql/mariadb client is available in the container" >&2
+                exit 1
+            fi
+
+            export MYSQL_PWD="${MYSQL_PASSWORD:-rustpad}"
+            exec "$client" --user="${MYSQL_USER:-rustpad}" "${MYSQL_DATABASE:-rustpad}"
+        '
+        ;;
+esac
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