Method handle_table_existence_query

src/session/db_handler.rs:2711–2747

Handle SQLAlchemy table existence check query This optimizes the complex JOIN query by doing a simple table lookup

(&self, query: &str, session_id: &Uuid)

    /// Handle SQLAlchemy table existence check query
    /// This optimizes the complex JOIN query by doing a simple table lookup
    async fn handle_table_existence_query(&self, query: &str, session_id: &Uuid) -> Result<DbResponse, PgSqliteError> {
        // Extract table name from the query
        // Look for patterns like "relname = 'table_name'" or "relname = $1"
        let table_name = if let Some(captures) = RELNAME_REGEX.as_ref()
            .ok()
            .and_then(|regex| regex.captures(query)) {
            captures[1].to_string()
        } else {
            // For parameterized queries, we need to look at the actual parameters
            // For now, return empty result to indicate table doesn't exist
            // This will cause SQLAlchemy to proceed with CREATE TABLE
            return Ok(DbResponse {
                columns: vec!["relname".to_string()],
                rows: vec![],
                rows_affected: 0,
            });
        };
        
        debug!("Checking table existence for: {}", table_name);
        
        // Simple table existence check
        let existence_query = "SELECT name FROM sqlite_master WHERE type IN ('table', 'view') AND name = ? AND name NOT LIKE 'sqlite_%' AND name NOT LIKE '__pgsqlite_%'";
        
        self.connection_manager.execute_with_session(session_id, |conn| {
            let mut stmt = conn.prepare(existence_query)?;
            let rows: Result<Vec<_>, _> = stmt.query_map([&table_name], |row| {
                let name: String = row.get(0)?;
                Ok(vec![Some(name.into_bytes())])
            })?.collect();
            
            Ok(DbResponse {
                columns: vec!["relname".to_string()],
                rows: rows?,
                rows_affected: 0,
            })
        })
    }

    /// Store CREATE TABLE metadata including type mappings and numeric constraints
    fn store_create_table_metadata(