Call Level Interface
Designing the Call Level Interface:
Before going to implement the system, the CLI must be designed in detail. Otherwise it would be too difficult to change the CLI in later phases of development. Let’s discuss on the practical aspects of CLI design. The design of CLI must consider the following :
- Simple to use.
- Must be aware of system capabilities and allow applications to access full potential of Data Processor.
- Must be efficient.
- Handle preprocessed/raw calls.
- Development and maintenance must be convenient.
We need to define various calls or structures that can hold the SQL/Data information. The Call Level Interface will need more or less the following control structures.
# Admin Control Block : The admin block should be designed separately, because it should support all the special privileges available to administrator. The privileges may be starting/stopping the system, running preventive validations on data, checking/managing the current connections/sessions, etc.
# System Control Block : The system control parameters can be stored that would be used by every query comming through the CLI.
# Application Parameter Block :This will have the instructions sent by the external application.
# Session Manager Block : This will contain the session specific information.
# Request Handler Block : This will include the request specific details.
# Buffer Control Block : This will keep the details of buffer used by the CLI calls.