Data in a Microsoft Office Excel workbook that has been displayed in Excel Services can come from two different locations. The data may be stored directly in the workbook, or it may be stored in an external data source, such as in a database or in
Data in a Microsoft Office Excel workbook that has been displayed in Excel Services can come from two different locations. The data may be stored directly in the workbook, or it may be stored in an external data source, such as in a database or in an Online Analytical Processing (OLAP) cube.
If the data comes from an external data source, the workbook author or administrator has defined the connection information, often in an Office data connection (.odc) file, which describes how to locate, log in, query, and access the external data source.
When you are connected to an external data source, you can perform a refresh operation to retrieve the updated data. Each time that you refresh data, you see the most recent version of the data, including any changes that were made to the data since it was last refreshed.
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Learn about refreshing data
The following illustration explains the basic process of what happens when you refresh data connected to an external data source.
A refresh operation gets up-to-date data.
A connection, often saved to a connection file, defines all the information needed to access and retrieve data from an external data source.
There are a variety of data sources you can access, such as OLAP, SQL Server, OLEDB providers, and ODBC drivers.
Up-to-date data is added to the current workbook.
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Learn about security concerns
When you are connected to an external data source and you attempt to refresh the data, it's important to be aware of potential security issues, and to know what you can do about any security issues.
A data connection file often contains one or more queries that are used to refresh external data. By replacing this file, a user who has malicious intent can design a query to access confidential information and distribute it to other users or perform other harmful actions. Therefore, it's important to ensure that:
- The connection file was authored by a reliable individual.
- The connection file is secure and comes from a trusted Data Connection Library (DCL).
For more information on how an administrator can author connection files, create trusted locations, and secure connection files, see Microsoft Office Excel 2007 Help and Office SharePoint Server Central Administration Help.
Security Accessing an external data source usually requires credentials (such as a user name and a password) that are used to authenticate the user. Make sure that these credentials are provided to you in a safe and secure manner, and that you do not inadvertently reveal these credentials to others.
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Control how data is refreshed
You can control how to refresh data from an external data source by doing one or more of the following:
Refresh on open
In Microsoft Office Excel 2007, a workbook author can create a workbook that automatically refreshes external data when the workbook is opened by selecting the Refresh data when opening the file check box in the Connection Properties dialog box. (On the Data tab, in the Connections group, click Connections, select the connection, click Properties, click the Usage ta