Connection information file created by Microsoft Excel, a spreadsheet application included with Microsoft Office; contains properties to connect to, and retrieve data from, an external data source; may include a connection string, data queries, authentication information, and other settings.

Office Data Connection (ODC) files are used to store reusable connection and data query information. This is useful for sharing connection information, as well as for performing periodic data refreshes within an Excel workbook. ODC files can be created using the Data Connection Wizard in Microsoft Excel, which generates the connection information using HTML markup with included segments of XML. Existing data connections may be viewed in Excel by selecting Data → Connections. NOTE: Since ODC files are stored using HTML and XML, they are viewable in any Web browser or text editor. ODC files are used by Microsoft Excel 2007 and later.