Package weka.experiment

Class InstanceQuery

  • All Implemented Interfaces:
    java.io.Serializable, OptionHandler, RevisionHandler
    public class InstanceQuery
extends DatabaseUtils
implements OptionHandler
    Convert the results of a database query into instances. The jdbc driver and database to be used default to "jdbc.idbDriver" and "jdbc:idb=experiments.prp". These may be changed by creating a java properties file called DatabaseUtils.props in user.home or the current directory. eg: 

     jdbcDriver=jdbc.idbDriver
 jdbcURL=jdbc:idb=experiments.prp

    Command line use just outputs the instances to System.out.

    Valid options are: 

     -Q <query>
  SQL query to execute.
 
     -S
  Return sparse rather than normal instances.
 
     -U <username>
  The username to use for connecting.
 
     -P <password>
  The password to use for connecting.
 
     -D
  Enables debug output.
    Version:
    $Revision: 11887 $
    Author:
    Len Trigg (trigg@cs.waikato.ac.nz)
    See Also:
    Serialized Form

    • Constructor Detail

      • InstanceQuery

        public InstanceQuery()
              throws java.lang.Exception
        Sets up the database drivers
        Throws:
        java.lang.Exception - if an error occurs

    • Method Detail

      • listOptions

        public java.util.Enumeration listOptions()
        Returns an enumeration describing the available options

        Specified by:
        listOptions in interface OptionHandler
        Returns:
        an enumeration of all options

      • setOptions

        public void setOptions​(java.lang.String[] options)
                throws java.lang.Exception
        Parses a given list of options. Valid options are: 

         -Q <query>
  SQL query to execute.
 
         -S
  Return sparse rather than normal instances.
 
         -U <username>
  The username to use for connecting.
 
         -P <password>
  The password to use for connecting.
 
         -D
  Enables debug output.
        Specified by:
        setOptions in interface OptionHandler
        Parameters:
        options - the list of options as an array of strings
        Throws:
        java.lang.Exception - if an option is not supported

      • queryTipText

        public java.lang.String queryTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • setQuery

        public void setQuery​(java.lang.String q)
        Set the query to execute against the database
        Parameters:
        q - the query to execute

      • getQuery

        public java.lang.String getQuery()
        Get the query to execute against the database
        Returns:
        the query

      • sparseDataTipText

        public java.lang.String sparseDataTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • setSparseData

        public void setSparseData​(boolean s)
        Sets whether data should be encoded as sparse instances
        Parameters:
        s - true if data should be encoded as a set of sparse instances

      • getSparseData

        public boolean getSparseData()
        Gets whether data is to be returned as a set of sparse instances
        Returns:
        true if data is to be encoded as sparse instances

      • getOptions

        public java.lang.String[] getOptions()
        Gets the current settings of InstanceQuery
        Specified by:
        getOptions in interface OptionHandler
        Returns:
        an array of strings suitable for passing to setOptions()

      • retrieveInstances

        public Instances retrieveInstances()
                            throws java.lang.Exception
        Makes a database query using the query set through the -Q option to convert a table into a set of instances
        Returns:
        the instances contained in the result of the query
        Throws:
        java.lang.Exception - if an error occurs

      • retrieveInstances

        public Instances retrieveInstances​(java.lang.String query)
                            throws java.lang.Exception
        Makes a database query to convert a table into a set of instances
        Parameters:
        query - the query to convert to instances
        Returns:
        the instances contained in the result of the query, NULL if the SQL query doesn't return a ResultSet, e.g., DELETE/INSERT/UPDATE
        Throws:
        java.lang.Exception - if an error occurs

      • main

        public static void main​(java.lang.String[] args)
        Test the class from the command line. The instance query should be specified with -Q sql_query
        Parameters:
        args - contains options for the instance query