fix: handle result sets for SHOW, CREATE TABLE, and DESCRIBE commands

[designcomputer]

Fix: Handle Result Sets for SHOW, CREATE TABLE, and DESCRIBE Commands

Problem

When executing SHOW INDEX FROM table_name, SHOW CREATE TABLE table_name, or DESCRIBE table_name through the MCP tool, it returns an error: "Error executing query: Unread result found". This happens because the code was specifically checking for queries that start with "SELECT" rather than checking if the query returns a result set.

Solution

This PR changes the condition from checking the query syntax (query.strip().upper().startswith("SELECT")) to checking the existence of a result set (cursor.description is not None). This makes the code more robust and allows it to handle all types of queries that return result sets, not just SELECT queries.

Additionally, it adds more robust error handling for result fetching operations and improves debug output.

Changes Made

1. Changed the condition from:

elif query.strip().upper().startswith("SELECT"):

To:

elif cursor.description is not None:

2. Added error handling for fetchall():

try:
    rows = cursor.fetchall()
    # Process rows...
except Error as e:
    logger.warning(f"Error fetching results: {str(e)}")
    return [TextContent(type="text", text=f"Query executed but error fetching results: {str(e)}")]

3. Added additional debug output to stderr for better troubleshooting

Testing

I've tested this change with various command types:

• SELECT queries: Work as before
• SHOW CREATE TABLE: Now works correctly
• SHOW INDEX: Now works correctly
• DESCRIBE: Now works correctly

Related Issues

This PR addresses PR #7 which introduced a similar fix but didn't include the additional error handling.