A project team needs to consider the following questions before choosing a data access technology:
Developers can use differing data access technologies to implement useful data access and application communication strategies; such strategies are listed in Table 9.7.
Table 9.7 Key characteristics for data access technologies
Best choice is… | If the application requires… | Remarks |
---|---|---|
ADO | Mainframe data or programcommunications | With Microsoft SNA Server, developers can set up OLE DB data providers for mainframe data sources such as VSAM, CICS, IMS, and AS/400 files. |
Reengineering | For existing applications, developers should consider reengineering with ADO. As an alternative, developers could continue with previous data access methods. | |
New development | For all new development, use Microsoft's ADO data access technology. | |
Uniform access to a variety data sources and data types | ADO is a common interface for all data access of requirements. | |
Fast development | ADO helps minimize development cost because it is uniform, consistent, and easy to use. The team can be trained once and benefit continuously thereafter. | |
High performance | ADO provides rapid performance. | |
Web: Internet Information Service's (IIS) Active Server Pages (ASP) | If the application uses IIS with ASP to generate browser-independent HTML from databases, use ADO. | |
OLE DB | Custom File Access | The team can write custom OLE DB data providers for virtually any data source. Once written, ADO can then be used as the data access technology. |
RDO | Fast access to existing ODBC data | RDO is very fast. |
ODBCDirect | Access to ODBC data | ODBCDirect provides a performance improvement over the older DAO data access technology. |
DAO | Enhancements to existing data access | DAO provides a consistent programming model for DAOsituations where some of the data access services must be provided using Microsoft Jet. If developers already have large amounts of DAO code and are willing to over- look the design, coding, and performance benefits provided by ADO, there's no reason to change it. |
Running within a 16-bit environment | DAO is the only choice. | |
ODBC API | Fast access to existing ODBC data | If the team is willing to develop and maintain complex code using the ODBC API, this is a good choice. |