What is the ADX file format?
.ADX index files for Lotus Approach databases allow the application to locate records quickly, storing offset data that maps field values to their positions in the paired .DBF data file. This binary index format accelerates query and search operations in Approach's relational database engine. It was used throughout the Lotus SmartSuite era; IBM Lotus SmartSuite 9.8 (2002) was the final release, and the product was officially discontinued around 2014. The SmartSuite software package, which included the Lotus/IBM Approach database systems, is no longer being developed and supported.
Creating .ADX Files in Relational Databases
.ADX index files for Approach databases were created automatically - users never generated them manually. These are known as SmartIndex files. They were saved by default in the same directory as the .DBF (or .DBT memo) database file. However, they may cause certain recurring problems:
- Their size is not verified, and they are created incrementally, which may cause them to occupy more disk space than the database itself over time.
- If the database is used by other applications, the
.ADXfile might become incorrect and outdated. - The file may store incorrect data due to errors, causing wrong indexes to be returned during searches.
These situations in Approach databases can usually be remedied by compacting the database, or by deleting or repairing the .ADX file - Approach will rebuild it automatically on next open.
Possible Consequences of Deleting an .ADX File in Approach dBase
In certain cases of maintaining databases and working with .ADX files, complications may arise. If the database has field names that do not comply with the dBase IV format, uses automatically increasing serial numbers, or is also utilized by other software, deleting the .ADX file may disrupt its structure. Therefore, other methods of fixing problems with SmartIndex .ADX files have been developed for these situations.
Security & safety
RISK: LOWPure binary index file; contains no executable code. Risk is only from obsolete/unmaintained software needed to open it.
Format details
in a nutshell- CRI ADX Audio File - Proprietary lossy audio format by CRI Middleware (1996), widely used in Sega Dreamcast, GameCube, PS2, and later console games; starts with 0x80 0x00 header, ends '(c)CRI' marker. Supported by VGMStream, foobar2000 (foo_input_vgmstream), Audacity.
- AutoCAD Database Exchange File - Index or exchange file generated by some AutoCAD/ADE workflows; rare.
Programs that open ADX files
Windows2 apps
Lotus Approach (SmartSuite)
Paid Open the companion .APR project file; Approach loads the ADX index automatically. Software is EOL - no longer purchasable or officially supported.
Microsoft Access (data recovery only)
Paid Import the companion .DBF file (File → External Data → Import → dBASE file). ADX index itself is not importable, but the DBF data can be recovered. Technical details
deep spec| File type | Binary index companion to Lotus Approach .APR and .DBF database files |
| Encoding | Binary, little-endian |
| Index function | Stores record-location offsets to accelerate queries on dBase-format tables |
| Creation | Auto-generated by Lotus Approach; never created or edited by users directly |
| Default location | Same directory as the paired .DBF data file |
| Growth issue | Created incrementally without size verification - can grow larger than the database itself over time |
| Staleness risk | Becomes outdated if the .DBF is modified by another application while Approach is not open |
| Rebuild trigger | Deleting the .ADX causes Approach to regenerate it automatically on next open |
| Deletion risk | May disrupt the database if field names are non-dBase-IV-compliant or auto-increment fields are in use |
| Platform | Windows (IBM Lotus SmartSuite environment) |
| Software era | Lotus Approach 3.0 (1994) through SmartSuite 9.8 (2002); product discontinued approximately 2014 |
| Typical file size | Under 1 MB (index overhead for a database table) |
| Released | 1994 (Lotus Approach 3.0) |
| Latest version | Lotus Approach 9.8 / SmartSuite 9.8 (2002) |
ADX conversions
Community Q&A
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