Query Capabilities: Search Methods and Wrappers

Some sources offer limited query capabilities. For instance, most web sources can only be queried with constraints imposed by a specific HTML query form.

The description of the query capabilities in Virtual DataPort is done through the so-called search methods. For each view, the administrator can define one or more search methods.

When creating a search method, the following elements should be specified: the list of query constraints, the list of output attributes and the wrapper, created beforehand using the statement CREATE WRAPPER, which is responsible for extracting the data from the source.