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• Declaring the target concept space
  The coded node set (variable 'cns') is initially declared to query the NCI Thesaurus vocabulary. At this point the concept space included by the set can be thought of as unrestricted, addressing every defined coded entry (the 'false' value on the declaration indicates to also include inactive concepts). However, it important to note that no search is performed by the LexEVS service at this time.
• Applying filter criteria
  Similarly, no computation is performed (to realize query results) during invocation of the restrictToMatchingDesignations() and restrictToMatchingProperties() methods. However, these calls effectively narrow the target space even further, indicating that filters should be applied to the information returned by the LexEVS query service.
• Using the Lucene Query Syntax and other text matching functions
  • The text criteria applied in methods such as restrictToMatchingDesignations() uses one of a number of powerful text processing applications to provide the user with broad capability for text based searches. Text matches can be simple applications of exactMatch, startsWith or contains algorithms as well as powerful regular expressions and Lucene Query syntax (used in the LuceneQuery function.) As shown above these options are passed into the restrictToMatchingDesignations() Method as parameters.
  • Lucene Queries are well documented and can be very powerful. The uninitiated user may need some background on their use however. The user should start here with the official Lucene Query Parser documentation.
  • Keep in mind that some LexEVS queries such as "startsWith" and "contains" use wild card searches under the covers, so that use of wild cards in this context can cause errors in searches involving these search types.
  • Instead it is best to use the flexibility of the Lucene Query searches in the matchingDesignation by using the Lucene Query searches in LexEVS where most searches will work much as described in the query syntax documentation.
  • Special characters in the Lucene Query search can cause unexpected results. If you are not using special characters as recommended for various ** Lucene search mechanisms then your searches may not return expected results or may return an error. If the value you are searching upon contains say, parenthesis, you will need to place the value in quotations. The escape characters described in the Lucene Documentation do not work at this time.
  • Likewise you should not expect to see a Lucene Query narrow down search results as you progressively enter a longer substring more closely matching your term of interest. Instead use the contains method.
• Applying sorting criteria
  Multiple sort algorithms can be applied to control the order of items returned. In this case, we indicate that results are to be sorted based on primary and secondary criteria. The "matchToQuery" algorithm indicates to sort the result according to best match as determined by the search engine. The "code" item indicates to perform a secondary sort based on concept code.

  Info
  title Note
  the list of all available sort algorithms can be listed using the 'ListExtensions -s' admin script. Restricting the information returned for matching items The LexEVS API also allows the programmer to restrict the values returned for each matching concept. In this example, we chose to return only the UMLS CUI and assigned text presentations. Retrieving the result A query is finally performed during the 'resolve' step, with results returned to the declared list. It is at this point that the LexEVS service does the heavy lifting. By declaring the full extent of the request up front (namespace, match criteria, sort criteria, and returned values), the service then has the opportunity to optimize the query path. In addition, in this example we restrict the number of items returned to a maximum of 6. This combined approach has the benefit of reducing server-side processing while minimizing the volume and frequency of traffic between the client program and the LexEVS service. Info title Note While this section provides one example of combining criteria, this same pattern can be applied to many of the CodedNodeSet and CodedNodeGraph operations. It is strongly recommended that programmers familiarize themselves with this programming model and its application. Additional Resources Reserved for links to Code Snippets and Overview of the Software. LexEVS GUI The LexEVS Graphical User Interface, or GUI, is an optional component of the LexEVS install which will be in the /gui folder of the base LexEVS installation (see file breakdown in VKC:Overview of the Software). The GUI is meant to provide a simple tool to test LexEVS API methods and quickly view the results; almost all public methods defined by the LexEVS API are supported. This guide provides a brief overview of how the GUI can aid programmers in writing code to the LexEVS API. Info title Note The LexEVS GUI supports both administrative and test functions. Please refer to the LexEVS Administrator's Guide for instructions on using the GUI as an administration tool. Launching the GUI Depending on the operating systems that you selected at installation time, you should have one or more of the following programs in the /gui folder: Code Block Linux_64-lbGUI.sh Linux-lbGUI.sh OSX-lbGUI.command Windows-lbGUI.bat Launch the GUI by executing the appropriate script for your platform. You will be presented with an application that looks like this: Image Modified Overview The upper section of the GUI shows all of the code systems currently loaded, along with corresponding metadata. The lower section of the GUI is used to combine, restrict and resolve Code Sets and Code Graphs. The lower left section is where you can perform Boolean logic on Code Sets and Code Graphs. The lower right section is where you can introduce restrictions on Code Sets and Code Graphs and browse results. Info title Note The menu options are used primarily for administrative functions

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• and are covered in detail by the LexEVS

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• 5.x Administration Guide. In addition, all of the disabled buttons in the top half of the application are used for administrative functions, and are also described in the

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• Administration Guide.

Creating New Queries

There are four buttons on the top half that are of interest for creating queries.

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• Union - This button is enabled if two Code Sets or two Code Graphs are selected in the lower left. Clicking the button creates a new virtual Code Set or Code Graph which represents the Boolean union of the two selected items. All restrictions applied to the individual items still apply.
• Intersection - This button is enabled if two Code Sets or two Code Graphs are selected in the lower left. Clicking the button creates a new virtual Code Set or Code Graph which represents the Boolean intersection of the two selected items. All restrictions applied to the individual items still apply.
• Difference - This button is enabled if two Code Sets or two Code Graphs are selected in the lower left. Clicking the button creates a new virtual Code Set which represents the Boolean difference of the two selected Code Sets. All restrictions applied to the individual items still apply. *
• Restrict to Codes - This button is enabled if a Code Set and a Code Graph are selected in the lower left. Clicking the button creates a new virtual Code Graph which will be restricted to concept codes occurring in the selected Code Set.
• Restrict to Source Codes - This button is enabled if a Code Set and a Code Graph are selected in the lower left. Clicking the button creates a new virtual Code Graph which will have its source codes restricted to codes occurring in the selected Code Set.
• Restrict to Target Codes - This button is enabled if a Code Set and a Code Graph are selected in the lower left. Clicking the button creates a new virtual Code Graph which will have its target codes restricted to codes occurring in the selected Code Set.
• Remove - This button is enabled if any Code Set or Code Graph (or virtual Code Set or Code Graph) is selected in the lower left. Clicking the button will remove the selected item from the list.

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