Chapter 25. Basic Concepts

Table of Contents
Hostvariables
Statements
Resultset

This chpater gives an overview of the concepts of the ADBC interface.

The ADBC interface is based upon the following major components:

  1. Hostvariables

  2. Statements

  3. Resultsets

Hostvariables

Host variables are used to transfer data between the data base and the application. In a query the hostvariables are indicated by a name preceeded by an ':' in a query. The API allowes to associcate Ada 95 host variables with these names. An Ada 95 hostvariable provides the value and the additional attribute Is_Null to the application programmer, which means the variable is has a value or is not set.

Driver dependencies: Not all database drivers do provide the null indication for a colon in the result set. As a consequence the driver may not be able to support this. The driver should always return true and a defined value.