Microsoft Excel is a commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. Pre-2007 versions of Excel use XLS as the primary format for saving files. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications. It has been a very widely applied spreadsheet for these platforms, especially since version 5 in 1993, and it has almost completely replaced Lotus 1-2-3 as the industry standard for spreadsheets. Excel forms part of Microsoft Office. The current versions are 2010 for Microsoft Windows and 2011 for Mac OS X.
Microsoft Excel up until 2007 version used a proprietary binary file format called Binary Interchange File Format (BIFF) as its primary format. Used as the basis for XLS files it is a persistence format that supports authoring and manipulating content in workbooks and workbook templates. Most versions of Microsoft Excel can read CSV, DBF, SYLK, DIF, and other legacy formats.
The MDB file extension was created by Microsoft and is the primary file type associated with the Microsoft Access applicaiton, which forms part of the Microsoft Office product set. The file type rose in popularity as a result of the success of Microsoft Office and is a popular relational database file type due to its simplicity for creation and use by a novice. An .mdb file contains fields, rows, tables, forms, macros, queries and reports.
An .mdb file extension can either be a self contained database based on its own Access Jet Database or be used as the front end representation with the backend linking to any ODBC compliant application such as Microsoft Excel, XML, SQL and Microsoft SharePoint. MDB files can be used to create simple applications. MDB files do not scale particularly well, with 1GB being the threshold in terms of file size before performance deteriorates.