|What is VO2Jet ?
||VO2Jet is a Class Library for CA-Visual Objects (VO) that gives VO developers an efficient and easy to use interface to the Microsoft Jet Engine, the database engine behind Microsoft Access, Microsoft Visual Basic and Microsoft Visual C++.
The Class library consists of a set of classes that talk directly to the Microsoft Jet engine using the DAO programming layer.
It also has a set of higher level DbServer compatible classes that allows VO developers to use the Jet Engine in combination with the VO DataWindow and Databrowser classes.
||VO2Jet comes with its own Editor subsystem that integrates into the VO Integrated Development Environment. This subsystem generates both the necessary binary entities to use Jet databases with the autolayout function in the Window Editor, and also generates sourcecode for the Jet database classes. The sourcecode generation is template based, so highly configurable. (For creating and maintaining databases we recommend other tools such as Microsoft Access)
||VO2Jet comes with full source code to the class library and a number of samples, and with documentation in the form of a Windows Online Help file.
|Who should use VO2Jet ?
||VO2Jet is invaluable for Visual Objects developers that have to interface to applications written in Microsoft Access, Microsoft Visual Basic of Microsoft Visual C++ .
VO2Jet can also be of use to those developers that are looking for an powerful and easy to use alternative for the DBF databases. The Microsoft Jet Engine has a number of powerful features such as referential integrity and transaction support.
|What is the Microsoft Jet Engine ?
||The Microsoft Jet Engine is the database engine that is included with products such as Microsoft Visual Basic, Microsoft Visual C++ and Microsoft Access. Since these are three very popular development environments, a lot of commercial applications also use the Microsoft Jet Engine to store their data.
The Microsoft Jet Engine offers developers access to a number of different database formats:
- Microsoft Access MDB Databases
- Microsoft FoxPro, versions 2.0, 2.5, 2.6, 3.0, and DBC
- dBASE III, dBASE IV, and dBASE 5.0
- Paradox, versions 3.x, 4.x, and 5.x
- Microsoft Excel versions 3.0, 4.0, 5.0, and 8.0 worksheets
- Lotus 1-2-3 WKS, WK1, WK3, and WK4 spreadsheets
- ASCII text files in tabular format
- Microsoft Exchange and Outlook folders and address books
- Microsoft Jet, versions 2.x
- All ODBC Data sources
The Microsoft Jet engine allows developers to use access data both with a record oriented approach and with a set oriented approach (using SQL syntax). Queries can mix tables from different database formats, and a Query optimizer is included in to get fast response even with complex queries.When using tables in the Access database format the Microsoft Jet engine supports referential integrity including cascading & restricted updates & deletes! It also includes transaction support for Access data and for ODBC data (if driver supports it). Finally includes on the fly encryption and authorization for the Access Databases.The programming interface to the Microsoft Jet Engine is called Data Access Objects (DAO) and consist of a complete object model that allows developers to create databases, tables and queries and to access and update data.
VO2Jet uses this DAO programming interface to talk to the Microsoft Jet Engine.
List of the most important VO2Jet classes
|VO DataServer classes
These classes allow you to use the Jet databases in a similar way as you use the DbServer and SqlSelect classes that come with VO.
These classes are added to VO2Jet to handle different data types that are not available in Visual Objects:
|DAO wrapper classes
You can use these classes to directly talk to the Microsoft Jet Engine. They allow you to query and update the database definition and to retrieve and update data.
- DaoConnection DaoContainer DaoDatabase DaoDbEngine DaoDocument DaoError DaoField DaoGroup DaoIndex DaoParameter DaoProperty DaoQueryDef DaoRecordset DaoRelation DaoTableDef DaoUser
These classes allow you to access the various collections of objects that the Jet Engine uses
||To use VO2Jet you need to have:
- A computer with Windows 95, Windows 98 or Windows NT 4.0
- CA-Visual Objects 2.0b-3
- To use Vo2Jet, you also need to have a valid license and a functioning installation of the Microsofts Jet engine version 3.5 and DAO 3.5 (Data Access Objects). This is the case if you have completely installed Microsoft Office Professional for Windows 97, Microsoft Access for Windows 97, Visual Basic Professional 5.0, or Visual C++ 5.0.