Database Applications in IIS
ActiveX? Data Objects (ADO) and ADO.NET provide a common programming model for any OLE DB data source; it is essentially a collection of objects that expose the attributes and methods used to communicate with a data source. ADO uses general OLE DB providers to access unique features of specific data sources; it also uses native OLE DB providers, including a specific OLE DB provider that provides access to Open Database Connectivity (ODBC) drivers. Designed to replace the need for all other high-level data access methods, ADO can access relational, Indexed Sequential Access Method (ISAM), or hierarchical databases, or any type of data source-as long as there is an ODBC-compliant driver.
ADO
ADO's ease of use, speed, and low memory overhead make it ideal for server-side scripting. In fact, ADO is the recommended technology for data access for ASP applications. ADO can be called directly from server-side scripts or from business components.
Unlike earlier data access methods, ADO does not require navigation through a hierarchy to create objects; most ADO objects can be created independently, which allows greater flexibility in reusing objects in different contexts and reduces memory consumption. ADO also takes advantage of ODBC 3.0 connection pooling for ODBC data sources, and session pooling for OLE DB providers. This eliminates the need to continuously create new Connection objects for each user, which is very resource intensive.
OLE DB, the foundation of the Universal Data Access model, is a set of COM interfaces that provides a standard way for programs to access data. The way your application uses ADO functionality will be partially determined by whether or not there is an OLE DB provider for the data. ADO is designed to work with OLE DB, and in most instances your ADO components will communicate with databases through OLE DB; you can also use ADO to communicate directly with the ODBC driver, if no OLE DB provider is available. Using ADO through an OLE DB provider has an impact on using stored procedures and choosing the client networking library.
For example of code that uses ADO, see ADO Code Examples in the ActiveX? Data Objects (ADO) SDK. For specific examples of ASP code that use ADO, see Accessing Databases in IIS Applications
ADO.NET
Complete information about developing ADO.NET applications can be found in the .NET Framework SDK under Accessing Data with ADO.NET.
The following topics are examples of information that is described in that section: