Map the complete connection path
- Identify whether Delphi reaches ODBC through BDE, ADO or another component layer.
- Match application architecture to the correct 32-bit or 64-bit ODBC administrator and driver.
- Record system/user DSN scope, or test the exact DSN-less connection string.
- Capture the full ODBC diagnostic chain, not only the first message shown by a component.
- Test authentication, DNS, port and server reachability outside the application.
A DSN visible in a 64-bit administrator is invisible to a 32-bit process. Likewise, a successful driver connection does not prove that the surrounding BDE alias or Delphi component properties are correct.
Problems after connection
| Query syntax fails | Driver/database SQL dialect, identifier quoting or unsupported functions. |
|---|---|
| Text is damaged | Application, driver and server disagree on ANSI code page or Unicode handling. |
| Parameters differ | Type, size, order or date/decimal conversion is implicit. |
| Intermittent disconnect | Network, server timeout, pooling or stale connection state. |
Keep a minimal connection/query test beside the full application. It isolates driver and server behavior without BDE aliases, forms or business logic obscuring the result.
See Delphi SQL Server integration, BDE deployment and the Delphi pillar.