.mdb File — Microsoft Access Database

MDB (Microsoft Database) is the file format used by Microsoft Access 97 through 2003 for storing relational databases. MDB files contain tables, queries, forms, reports, macros, and VBA code modules in a single binary file using the Microsoft Jet Database Engine. The format supports relational tables with primary keys, foreign key relationships, indexes, data validation rules, and input masks. MDB files can contain up to 2 GB of data and support concurrent multi-user access through record-level locking and optimistic concurrency. Microsoft Access and MDB files have been widely used for small business applications, departmental databases, personal data management, and rapid application development. The visual query designer, form builder, and report generator made Access one of the most approachable database development environments. MDB files support ODBC connections for linking to external databases and can serve as data sources for other applications. The format was superseded by ACCDB in Access 2007, which added enhanced security (removing VBA code storage vulnerabilities), attachment data type, multi-valued fields, and integration with SharePoint. Legacy MDB files remain common in organizations that built custom Access applications over many years.