You can use the Microsoft Jet database engine to access other popular desktop database files, spreadsheets, Microsoft Exchange and Microsoft Outlook folders and address books, tables in HTML files, and textual data stored in tabular format. One way to access external data is through installable indexed-sequential access method (IISAM) drivers. These are called ISAM databases because Microsoft Jet accesses them using IISAM drivers. The IISAM drivers expose the desktop database to Data Access Objects (DAO) as a Microsoft Jet database, supporting most of the querying, searching, and data-definition functionality of a native Microsoft Jet database file.
All external data sources are considered either Open Database Connectivity (ODBC) databases or desktop databases. With DAO 3.5, you can connect to ODBC databases either by using the Microsoft Jet database engine or through an ODBCDirect workspace.
See Also For information about how to access external data through ODBC and how to use ODBCDirect, see Chapter 9, “Developing Client/Server Applications.”
Supported desktop database IISAM formats include older versions of Microsoft Jet, Microsoft FoxPro, dBASE, and Paradox. Supported spreadsheets include Microsoft Excel and Lotus 1-2-3. Additional support is provided for Microsoft Exchange and Outlook folders and address books, HTML tables and lists, and text files in character-delimited and fixed-length formats.
This chapter discusses general strategies and techniques for accessing external data through IISAM drivers and linked ODBC tables and includes specific examples. In addition, it provides detailed information on managing access to text data.
Understanding Data Sources and Access Methods
Establishing Access to External Data
Performance Optimization and Troubleshooting Tips
You can use the code examples in this chapter to help you understand the concepts discussed, or you can modify them and use them in your own applications.
The code examples are located in the JetBook\Samples subfolder on the companion CD-ROM. The code examples for Microsoft Access 97 are in JetSamples.mdb, and the corresponding code examples for Microsoft Visual Basic version 5.0 and other applications that support Visual Basic for Applications are referenced in JetSamples.vbp. Both JetSamples.mdb and JetSamples.vbp use tables and queries in NorthwindTables.mdb, also located in the JetBook\Samples subfolder.
Examples in this chapter also use files in external data formats. The dBASE sample files are located in the JetBook\Samples\dBASE folder. The Microsoft Excel sample files are located in the JetBook\Samples\Excel folder. The Microsoft FoxPro sample files are located in the JetBook\Samples\FoxTables folder. The HTML sample files are located in the JetBook\Samples\HTML folder. The Paradox sample files are located in the JetBook\Samples\Pdx folder. The text sample files are located in the JetBook\Samples\Text folder.
To use the code examples, copy the sample files to your hard disk. Be sure to copy NorthwindTables.mdb as well so that you can use the code examples to work with data.
See Also For more information about copying and using the code examples from the companion CD-ROM, see “Using the Companion CD-ROM” in the Preface.