A primary purpose of MORPHO is to help the ecologist find data of interest. Since the data is described by metadata, finding data requires searches (queries) of metadata collections.
MORPHO allows the user to search metadata in a variety of ways. The most straightforward is a simple full text search for a word or phrase. This capability can be carried out in the toolbar using the 'QuickSearch' button. Other more powerful searches can be carried out using several screens which appear under the "Search Documents" tab. The details are described elsewhere (and some are not yet implemented).
Note that searches can be carried out both locally and on the centralized catalog system. The centralized catalog system uses an Oracle database and can potentially search a very large number of documents. The local search simply examines all XML files that are contained in a directory defined in the configuration files (see the "local_xml_directory" parameter for the name of that directory). Local searches use XPath expressions to carry out queries on each XML file (using the Xalan software from http://xml.apache.org) Local searches are much faster after the initial local search. This is because the local XML files are parsed and stored in memory the first time they are accessed. Subsequent searches use the DOM representations of the files that are stored in RAM. The number of local XML files that can be searched is thus limited by computer memory. Nevertheless, it appears that several thousand typical metadata files can be searched on a modern PC in a few seconds.