Add initial SQLmem package structure with SQL parser, cache manager, column registry, and tests

src/sqlmem/executor.py

@@ -0,0 +1,42 @@
+import sqlite3
+
+from loguru import logger
+
+from .cache import CacheManager
+from .parser import ParsedQuery
+from .registry import ColumnRegistry
+
+
+class QueryExecutor:
+    def __init__(self, cache: CacheManager, registry: ColumnRegistry, source_conn: sqlite3.Connection) -> None:
+        self._cache = cache
+        self._registry = registry
+        self._source_conn = source_conn
+
+    def execute(self, parsed: ParsedQuery) -> list[dict]:
+        table = parsed.table
+        columns = parsed.columns
+
+        missing = self._registry.needs_refetch(table, columns)
+        table_cached = self._cache.is_table_cached(table)
+
+        if missing or not table_cached:
+            if table_cached and missing:
+                logger.warning(
+                    f"Re-fetching {table!r} — new columns requested: {missing}. "
+                    f"Expanding cache from {self._registry.get_columns(table)} + {missing}"
+                )
+            all_columns = list(self._registry.get_columns(table)) + missing
+            self._cache.load_table(table, all_columns, self._source_conn)
+            self._registry.update(table, all_columns)
+        else:
+            logger.debug(f"Cache hit: {table!r} columns={columns}")
+
+        return self._run_in_memory(parsed)
+
+    def _run_in_memory(self, parsed: ParsedQuery) -> list[dict]:
+        logger.debug(f"Executing in SQLite RAM: {parsed.original_sql!r}")
+        cursor = self._cache.connection.execute(parsed.original_sql)
+        col_names = [desc[0] for desc in cursor.description]
+        rows = cursor.fetchall()
+        return [dict(zip(col_names, row)) for row in rows]