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IUMSC   Indiana University Molecular Structure Center

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Architecture

The old search examined the contents of one text file for each structure on the web server every time a search (but not "go to structure") was executed.  For a small number of structures this was fine, but with a large number of structures it became very slow.

The new search constructs a query and executes it against a database of structural information.  This will still slow down as the number of structures increases, but it is much faster than the old search all the same.



Classes of Users

There are three classes of users of the IUMSC search system, distinguished according to level of access.  From least access to most access they are

  • "guest" or "public" users,
  • research group users, and
  • IUMSC staff users.

Your user class is established based on how you enter the system and on what, if any, authorization credentials you present.  The "search" link on the IUMSC home page does not ask for credentials and provides access to the search engine as a guest user.  For greater access one must use the "Authorized User Options" link on the homepage and enter a valid username and password; the system determines the appropriate user class from the username.

Note: The username/password pairs used for research group access through the new search engine are the same as those that were (and are) used with the old MSC system, but the MSC staff must enter those passwords into the new system before they are active with the new search.  We have done so with those passwords of which we had records, but our security policy has generally been to not retain such records.  If you have difficulty obtaining access to the authorized user search then please contact the IUMSC staff for assistance.

Important: once you have logged on to the Authorized User Options, you must close the browser to cause those credentials to be discarded.  This is a limitation of the HTTP protocol.



Data Availability by User Class

The previous search interface often presented among its results structures inaccessible to the user because of password protection.  Both for improved security and for improved usability, the new search presents only those structures that the search user can actually access.  For public class users that means only structures that have been published or otherwise specially marked as accessible will be found.  For research group class users that means that in addition to those structures available to public class users, structures marked as belonging to that research group will be accessible as well.



Constructing a Query

The search form contains a large number of fields for various search criteria.  At least one field must be filled in.  As many criteria as are entered are conjoined to form the query, which is submitted to the database when the search button is clicked.  Results (if any) are presented in a table that includes for each hit the MSC number, the formulae, and the contents of the fields against which the query was conducted.  The MSC numbers in the results table are hyperlinks to the respective web data pages for the structures found.



Usage Notes

  • Searches on the comment, compound name, and formula fields are implemented as substring searches.
  • The "Structured Empirical Formula" criteria collectively are one of the more powerful new features.  Check them out as an alternative to searches on the empirical formula field!
  • Numeric fields on the search form specify a range search of the form value = x +/- y%.  The y parameter can be set to zero to specify an exact match.
  • Keywords are currently inconsistently implemented in the database, and as a result, keyword searches are not currently very useful.  This is an area of ongoing work.  Contact the MSC staff if you have suggestions for new keywords or for structures that should be flagged with one of the existing keywords.
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