Explicit Operation Specification for Component Databases

Database queries within a component framework usually take the form of a string passed to an operation in a component's interface. The interface operation accepts a value of type string as an actual parameter and implements the necessary support to resolve the query. In such an approach, a component's interface does not explicitly state the queries supported by that component. In this paper, we present an approach in which queries supported by a component are explicitly defined in its interface enabling a contract between a client of an interface and a component to be agreed. In our approach, a client creates a well-defined context within which interface operations can be executed. A context enables more complex queries to be constructed as sequences of related queries and saved contexts can be further combined to form more complex environments for query execution.