What are the best practices for handling parameters in an ODBC application to avoid "invalid descriptor index" and similar errors?

To consistently avoid this error and ensure robust ODBC parameter handling: 1. **Parametrization:** Always use parameterized queries (`?` placeholders) instead of string concatenation to prevent SQL injection and reduce parsing ambiguity. 2. **Accurate Parameter Counting:** Before binding, reliably count the number of `?` in your SQL string. Consider a utility function to ensure precision. 3. **Strict 1-Based Indexing:** Consistently use 1-based indexing for all ODBC functions dealing with parameters (`SQLBindParameter`) and columns (`SQLBindCol`, `SQLGetData`). 4. **Type Matching:** Ensure the C data type and SQL data type specified in `SQLBindParameter` (or `SQLBindCol`) accurately match the data being sent/received and the column/parameter definition in SQL Server. 5. **Correct Length Indicators:** Provide the `StrLen_or_IndPtr` in `SQLBindParameter` correctly for string and binary types. Use `SQL_NTS` for null-terminated strings and `SQL_NULL_DATA` for NULL values. 6. **Robust Error Checking:** Check the return code of *every* ODBC API call. If it's not `SQL_SUCCESS` or `SQL_SUCCESS_WITH_INFO`, retrieve diagnostic records immediately using `SQLGetDiagRec` for detailed error information. 7. **Resource Management:** Properly allocate, use, and deallocate all ODBC handles (environment, connection, statement) to prevent resource leaks and state corruption. 8. **Use Metadata Functions:** Leverage `SQLNumParams`, `SQLDescribeParam`, and `SQLNumResultCols` to dynamically query parameter and result set metadata, ensuring your application's expectations align with what the driver reports.