Linking Importing and Exporting Overview

Linking to external data means creating a pointer to an external data source that allows you to interact directly with the underlying data. Importing external data literally imports a copy of the data into your application. Exporting data refers to the idea of extracting data from your application to an external file or format.

Here are some situations when you should consider linking:

□ The data resides on a database server that your application and others can use.

□ The data is used by another program that requires the native file format.

□ The underlying data needs to be updated on a regular basis in its native format.

Here are some instances when you should consider importing:

□ An existing system is being migrated to a new application and the data from the old system will be used in the new application. (In some cases, you may be able to migrate to another system but keep the data on a database server without needing to import the data).

□ Numerous data operations must be run against the data from another source. You can obtain performance improvements by importing the data, but the underlying data will be out of sync if you make any changes to the data after it is imported.

Access allows you to link to and import from data sources such as Access (Jet) databases, SQL Server databases, other ODBC databases, Microsoft Sharepoint, XML documents, HTML documents, text files, Microsoft Exchange, Microsoft Outlook, and spreadsheets such as Microsoft Excel and Lotus.

Many of the techniques covered in this chapter can also be implemented using menus and wizards in Access. To import or link data using the menus and Wizards, select File C> Get External Data and then select either the Import or Link Tables option. You can export data by selecting a particular object (table, for example) in the Database Window, right-clicking, and selecting the Export option from the pop-up box.

Now that you understand the high-level concept of importing, linking, and exporting, you can jump right in to learning the techniques that will allow you to work with some of these supported data sources.

Create a blank database to use for the examples in this chapter. To do so, select File C> New C> Blank Database and specify Ch7CodeExamples for the filename and then click the Create button.

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