AllTopics (query directive)
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(Difference between revisions)
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Note that retrieving all topics of a large topic map can be very costly operation in terms of time. Thus whenever possible, try to avoid using this directive. If you for example want all topics that are instances of some other topic, instead of using something like new AllTopics().where(new IsOfType(a)) use new Instances().from(a). | Note that retrieving all topics of a large topic map can be very costly operation in terms of time. Thus whenever possible, try to avoid using this directive. If you for example want all topics that are instances of some other topic, instead of using something like new AllTopics().where(new IsOfType(a)) use new Instances().from(a). | ||
| + | |||
| + | == Examples == | ||
| + | |||
| + | importPackage(org.wandora.query2); | ||
| + | new BaseName().from(new AllTopics().as("#topic")) | ||
| + | .where("#DEFAULT","=",null) | ||
| + | |||
| + | This finds all topics in the topic map which do not have a base name. | ||
[[Category:Query directives]] | [[Category:Query directives]] | ||
Latest revision as of 11:14, 21 August 2009
Contents |
[edit] Description
Returns all topics of the topic map.
[edit] Constructor
AllTopics()
[edit] Notes
Note that retrieving all topics of a large topic map can be very costly operation in terms of time. Thus whenever possible, try to avoid using this directive. If you for example want all topics that are instances of some other topic, instead of using something like new AllTopics().where(new IsOfType(a)) use new Instances().from(a).
[edit] Examples
importPackage(org.wandora.query2);
new BaseName().from(new AllTopics().as("#topic"))
.where("#DEFAULT","=",null)
This finds all topics in the topic map which do not have a base name.
