Database and Transaction Overview


A key benefit of NAS is its ability to interact with multiple databases to handle issues such as connection caching and creation of database threads. This allows developers to work at a higher level of abstraction. Code can be generic with specific database configuration information housed outside the code.

Data Access Engine

Netscape has preserved the Data Access Engine (DAE) from previous versions of the server. The advantage is that the DAE is a proven, known component of the Netscape server. A newer improved version of the DAE, called DAE2, is incorporated in the product. Both DAEs can run simultaneously to allow for backward compatibility. The DAE talks directly to the Database Access Driver (DAD).

Written in C++; C++ has three major benefits:

  • Increases performance
  • Allows a transparent interface across all databases
  • Integrates with other core NAS services

JDBC

The JDBC driver handles calls to multiple database engines. JDBC calls directly to the DAD for each supported database. Therefore, developers do not have to write specific code to connect to each driver. This also allows NAS to handle connection caching and pooling.

NAS 4.0 assumes that calls to the database occur and loads the JDBC driver at engine startup time.

JDBC can be called from a servlet, JavaServer Page (JSP), and Enterprise JavaBean (EJB). The application architect makes the decision on how the application makes calls to JDBC.