Chapter 16: Working with External Data
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acquiring an Oracle ODBC driver. Not only are vendors supplying drivers for their own products,
but there are now software vendors who only create and supply ODBC drivers.Cross-Reference
Linking to ODBC sources is discussed in detail in Chapter 37. In that chapter, you’ll learn about setting up
ODBC data sources and linking to those sources. Although SQL Server is used as the example in Chapter 37,
the same principles apply to all ODBC data sources.
Linking to xBase files
Unlike Access, dBASE and FoxPro (and other xBase systems) store each table as a separate file with
a .dbf extension. Each .dbf file may be accompanied by an .ndx or .mdx file containing the
indexes associated with the dBASE table.When you link to a dBASE table, Access might ask you if you want to link to the index file associ-
ated with the dBASE table. In almost every case, you’ll want to include the index file in the linking
operation. Otherwise, the dBASE data will be read-only and not updatable.One other significant difference between Access and dBASE is that table and field names are much
shorter in dBASE than they are in Access, and they’re almost always expressed in all uppercase
characters.Linking to dBASE or other xBase data files is much like linking to an external Access table. The
main difference is that you select dBASE or FoxPro from the Files of Type drop-down list in the
File Open dialog box. Also, because each xBase file is a table, you don’t have to specify which table
to link. Otherwise, the processes are virtually identical.On the CD-ROM
This book’s CD includes a dBASE IV file named CONTACTS.dbf containing a copy of the Contacts table
from the Collectible Mini Cars application. You might want to use this file to practice linking the base tables.
Linking to non-database data
You can also link to non-database data, such as Excel, HTML, and text files. When you select one
of these types of data sources, Access runs a Link Wizard that prompts you through the process.Linking to Excel
The main issues to keep in mind when linking to Excel data arel (^) An Excel .xls spreadsheet file might contain multiple worksheets. You must choose
which worksheet within a workbook file to link (unless you’re using named ranges).
l (^) You may link to named ranges within an Excel worksheet. Each range becomes a separate
linked table in Access.