Free online S3DB to MDB converter

Applications built for Microsoft Access may require an .mdb database instead of an .s3db file, especially when importing legacy data or sharing it with older Windows systems. The conversion usually means moving tables from a SQLite database into an Access 2002–2003 database, not simply renaming the extension.

What the S3DB format is

.s3db is commonly used for a SQLite database. SQLite stores tables, indexes, views, triggers, and data in one portable file, so S3DB files are often found in desktop applications, embedded devices, mobile apps, scientific tools, and database utilities.

The extension is not a complete format specification: some programs may use S3DB for a specialized SQLite or SQLite-compatible database. Verify the file before converting. With the SQLite command-line utility, run sqlite3 input.s3db ".tables"; a list of tables confirms that the file is readable as SQLite.

What the MDB format is

.mdb is the Microsoft Access 2000–2003 database format. It supports relational tables, indexes, queries, forms, reports, and Access-specific relationships, and is useful when a legacy application or an older version of Microsoft Access cannot open the newer .accdb format.

MDB is not a SQLite container. Its data types, SQL syntax, relationship definitions, and metadata differ from those in S3DB, so a proper conversion creates new Access tables and transfers the records.

How to convert S3DB to MDB

Using Microsoft Access and an SQLite ODBC driver

1. Make a backup of input.s3db. Open the copy with a SQLite tool and check the tables, row counts, indexes, and views.
2. Install a compatible SQLite ODBC driver and create a system or user DSN pointing to the S3DB file. The driver must match the bitness of Microsoft Access: 32-bit Access needs a 32-bit driver, and 64-bit Access needs a 64-bit driver.
3. Open Microsoft Access and create a blank database. If Access creates an .accdb initially, that is acceptable during import.
4. Choose External Data → New Data Source → From Other Sources → ODBC Database, select Import the source data into a new table in the current database, choose the SQLite DSN, and select the tables to import.
5. Review each imported table. Set primary keys, indexes, relationships, required fields, and appropriate field sizes where Access did not infer them correctly.
6. Choose File → Save As → Access 2002–2003 Database (*.mdb). Reopen the resulting output.mdb and test representative queries and records.

Using an intermediate export

If an ODBC import is unavailable, export each SQLite table to CSV with a database utility or the SQLite command-line tool, then use External Data → New Data Source → From File → Text File in Access. A complete SQLite dump can be saved with sqlite3 input.s3db ".dump" > backup.sql, but SQLite SQL is not directly executable in Access; it requires schema and syntax changes before it can be used.

For a no-installation conversion, 101convert.com provides a free online S3DB-to-MDB conversion option. Use the desktop ODBC method for confidential databases or files containing data that should not be uploaded.

Compatibility and limitations

• SQLite dynamic typing does not map exactly to Access types. Check dates, Boolean values, large integers, decimal precision, and Unicode text after import.
• SQLite views and triggers generally do not become equivalent Access objects. Recreate them as Access queries, macros, or VBA code where required.
• Foreign-key relationships, collations, indexes, and autoincrement behavior may need manual reconstruction. Verify primary keys before creating relationships.
• Binary large objects, JSON stored as text, and custom SQLite extensions require application-specific handling.
• Access MDB has a maximum database size of approximately 2 GB, subject to Access version and system limitations. Compact and repair the database after a large import, then compare source and destination row counts.