What s New with Access 2000?

Access 2000 makes major strides in many areas. Microsoft has created a profoundly new product that still feels like the Access you know. This book highlights five specific areas of innovation: ActiveX Data Objects (ADO), enhanced SQL Server interoperability, Visual Basic for Applications (VBA) and packaging enhancements, Microsoft Jet engine improvements, and improved Web interoperability.

ActiveX Data Objects

ADO replaces nearly all of the data access functions that you previously performed with Data Access Objects (DAO). Access 2000 offers ADO functionality via three libraries: ADODB, ADOX, and JRO.

The ActiveX Data Objects 2.1 (ADODB) library offers core data access processing functions. The main ADODB objects include the Connection, Recordset, and Command objects. You can use these objects, along with their properties and methods, to connect to and manipulate a data source. The Connection object offers an interface to the new OLE DB provider technology. This technology is critical to the Microsoft Universal Data Access (UDA) architecture that provides high-performance access to a variety of data formats (both relational and nonrelational) on multiple platforms across the enterprise. UDA facilitates the integrated processing of traditional data sources, such as Jet and SQL Server data sources, with non-traditional sources, such as mail, file directories, and even video. UDA represents an evolutionary advance beyond today's standard data interfaces, such as Open Database Connectivity (ODBC), Remote Data Objects (RDO), and DAO.

The Microsoft ADO Extensions 2.1 for DDL and Security (ADOX) library offers an object-based approach to data definition and user-level security. It provides the traditional Jet user-level collections of Users and Groups. It ties permissions in database files to members of the Users and Groups collections in a workgroup information file. The ADOX model for this library tackles data definition chores using such objects as Tables, Columns, Indexes, Keys, Views, and Procedures. You can use these objects to dynamically define new tables, indexes, and relationships among tables. You can also define queries on the tables.

The Microsoft Jet and Replication Objects 2.1 (JRO) library primarily delivers Jet engine replication services through an ADO interface. This new ADO model lets you take advantage of all the new programmatic Jet database replication features. In addition, this model includes Jet engine functions such as compacting databases and refreshing the cache.

Enhanced SQL Server Interoperability

With Access 2000, you can process enterprise databases as easily as you work with Microsoft Jet databases. ADO connectivity is a part of the reason. However, integration is even tighter for SQL Server 6.5 and SQL Server 7 with the new Access Project. This new file type (.adp) works with SQL Server and Microsoft Data Engine (MSDE) databases in much the same way that .mdb files facilitate the processing of Jet databases. MSDE is a new database engine built on the SQL Server 7 model; it is meant for small workgroup solutions and complements the traditional Jet database engine. You can use either Jet or MSDE to develop solutions.

Access Projects explicitly expose views and procedures in the familiar database container framework. You can instantly connect to remote SQL Server databases, with the same graphical simplicity that you have with Jet databases. You can also use the SQL Server data with Access forms and reports (just as you do Jet data).

You also have seamless OLE DB interoperability with SQL Server and other back-end data sources. Using the ADO Connection object and OLE DB providers, you can connect to remote data sources and easily reference them programmatically for your custom applications.

VBA and Packaging Enhancements

Access continues to move toward VBA parity with the rest of Office. Access 2000 introduces a Visual Basic Editor (VBE) that has the same user interface as the one in Microsoft Word, Excel, and PowerPoint. You can transfer your code management and development skills directly to these other packages and thus enrich non-Access applications with data access functions.

The Office 2000 Developer Edition offers improved packaging and deployment options. For example, you can deploy solutions with MSDE and solutions that rely on a SQL Server-like database. You get the richness of views and procedures from the graphical interface as well as the programmatic interface. This is particularly important if an application might grow to require the capabilities of a full-fledged SQL Server database.

A new deployment option lets you deploy custom setup packages for your solutions via the Internet. You can thus vastly extend the range of clients that you serve. Your pool of potential development clients expands to include anyone around the globe with an Internet connection.

Jet Engine Improvements

Access 2000 ships with version 4 of the Jet database engine, which offers improvements in several areas of functionality. Particularly attractive is the availability of row-level page locking. Prior versions of Access performed locking at no lower than the page level. One reason for the introduction of row-level locking is the availability of Unicode support for text characters. You can now represent text data in different languages in multilingual applications. The new coding for text-based fields expands the space requirements for each character from 1 to 2 bytes and the page size from 2 to 4 KB. Since the page size has grown, Microsoft has enabled row-level locking to reduce the possibility of concurrent locks on the same page in multi-user applications.

Database replication has also improved in several areas. One improvement is the availability of column-level replication. In previous Jet versions, conflicts were detected at the row level so two replicas conflicted even if they changed different fields for the same record. Column-level replication improves performance by eliminating such conflicts. Access 2000 also introduces two-way replication between Jet and SQL databases. The prior version permitted only one-way replication from SQL Server to Jet.

Another praiseworthy improvement is programmatic control for changing the value of AutoNumber fields. You can set the initial and step values for AutoNumber fields when you create a table. You can also change these values for the next record in a table. In an Access Project, you can set AutoNumber fields from Table Design view. You can also change these values after a table is initially created.

Jet also offers SQL-level access to views and procedures. The Jet SQL improvements let you create and alter both types of database object models.

Improved Web Interoperability

One of the most significant new features of Access 2000 is data access pages, which act like Access forms and reports on the Web. You can design Web pages that bind directly to Jet or SQL Server data sources. With pages that act like forms, users can edit, add, and delete records graphically from a page. You can use design-time tools to programmatically control these features as well as sorting and filtering capabilities. While these pages do not enable subforms, you can create grouped data access pages that expand conditionally based on user input.

Data access pages can also serve as a host for the new Office 2000 Web Components, which you can use to create pages that contain interactive spreadsheets, dynamic charts, and pivot tables. You can also tie the spreadsheet and charting Web components to data displayed in grouped and ungrouped data access pages. This means that you can present calculations and charts that change dynamically as you move from one record to the next. Data access pages with pivot tables do not interact with other data sources on a page, but they do offer Excel-style "pivoting"—graphically moving parts of the data for a different view. In addition, pivot tables can be used for the analysis of multiple kinds of data, including SQL Server, Jet, and online analytical processing (OLAP) data sources.



Programming Microsoft Access 2000
Programming Microsoft Access 2000 (Microsoft Programming Series)
ISBN: 0735605009
EAN: 2147483647
Year: 1998
Pages: 97
Authors: Rick Dobson

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