Query topic map

Query topic map is a special topic map implementation in Wandora. A query topic map is defined by a number of queries in the Wandora query language. Each query will return one type of associations and the topic map consists of all these associations and the topics needed by the associations. All queries are executed in the context of some other topic map.

For example, you may define a query topic map with a query that will return the transitive closure of superclass-subclass associations. Then you give the query topic map a context topic map where this query will be executed. This will produce a topic map that seemingly contains the superclass-subclass associations making up the closure of such associations in the context topic map.

Setting up a query topic map

To set up a query topic map you need to make a new query topic map layer. Right click on the layer stack at lower left corner and select New Layer. Give your layer a name and select the Query type. For the query topic map to contain anything, you will need to add one or more queries. You can edit or add new queries also later by right clicking the layer and selecting Configure Layer. See next chapter about creating queries.

You will also need to set the context topic map. You can do this by dragging any layer in the layer stack under the query topic map layer or creating a new topic layer map under it. Note that the contents of the context topic map are not directly visible when it is under query topic map. Only contents produced by the query topic map are visible. For this reason you will usually want to create a special linked topic map. A linked topic map is a link to some other topic map in the layer and will contain everything in the topic map the link is pointing to contains. All edits made to either the linked topic map or the link target are reflected in the other. This way you can use a query topic map to complement another topic map, for example produce a transitional closure of associations.