src/query/executor/db.py

"""DbExecutor — runs compiled SQL on a user's external DB.

Pipeline:
  IR → SqlCompiler → SQL string + params
       ↓
  sqlglot validation (SELECT-only, whitelist tables/columns, LIMIT enforced)
       ↓
  asyncpg / pymysql in read-only transaction with timeout (30s)
       ↓
  QueryResult
"""

from ...catalog.models import Catalog
from ..compiler.sql import SqlCompiler
from ..ir.models import QueryIR
from .base import BaseExecutor, QueryResult


class DbExecutor(BaseExecutor):
    def __init__(self, catalog: Catalog) -> None:
        self._catalog = catalog
        self._compiler = SqlCompiler(catalog)

    async def run(self, ir: QueryIR) -> QueryResult:
        raise NotImplementedError