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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc (build 1.4.2_05) on Mon Mar 07 15:27:50 NZDT 2005 --><TITLE>DatabaseLoader</TITLE><META NAME="keywords" CONTENT="weka.core.converters.DatabaseLoader class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="DatabaseLoader";}</SCRIPT></HEAD><BODY BGCOLOR="white" onload="windowTitle();"><!-- ========= START OF TOP NAVBAR ======= --><A NAME="navbar_top"><!-- --></A><A HREF="#skip-navbar_top" title="Skip navigation links"></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""><TR><TD COLSPAN=3 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../Tutorial.pdf"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="http://www.cs.waikato.ac.nz/ml/weka/index.html"><FONT CLASS="NavBarFont1"><B>Weka's home</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../weka/core/converters/DatabaseConnection.html" title="class in weka.core.converters"><B>PREV CLASS</B></A> <A HREF="../../../weka/core/converters/DatabaseSaver.html" title="class in weka.core.converters"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../index.html" target="_top"><B>FRAMES</B></A> <A HREF="DatabaseLoader.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT> <A HREF="../../../allclasses-noframe.html"><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | <A HREF="#field_summary">FIELD</A> | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: <A HREF="#field_detail">FIELD</A> | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><A NAME="skip-navbar_top"></A><!-- ========= END OF TOP NAVBAR ========= --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">weka.core.converters</FONT><BR>Class DatabaseLoader</H2><PRE>java.lang.Object <IMG SRC="../../../resources/inherit.gif" ALT="extended by"><A HREF="../../../weka/core/converters/AbstractLoader.html" title="class in weka.core.converters">weka.core.converters.AbstractLoader</A> <IMG SRC="../../../resources/inherit.gif" ALT="extended by"><B>weka.core.converters.DatabaseLoader</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD><A HREF="../../../weka/core/converters/BatchConverter.html" title="interface in weka.core.converters">BatchConverter</A>, <A HREF="../../../weka/core/converters/DatabaseConverter.html" title="interface in weka.core.converters">DatabaseConverter</A>, <A HREF="../../../weka/core/converters/IncrementalConverter.html" title="interface in weka.core.converters">IncrementalConverter</A>, <A HREF="../../../weka/core/converters/Loader.html" title="interface in weka.core.converters">Loader</A>, <A HREF="../../../weka/core/OptionHandler.html" title="interface in weka.core">OptionHandler</A>, java.io.Serializable</DD></DL><HR><DL><DT>public class <B>DatabaseLoader</B><DT>extends <A HREF="../../../weka/core/converters/AbstractLoader.html" title="class in weka.core.converters">AbstractLoader</A><DT>implements <A HREF="../../../weka/core/converters/BatchConverter.html" title="interface in weka.core.converters">BatchConverter</A>, <A HREF="../../../weka/core/converters/IncrementalConverter.html" title="interface in weka.core.converters">IncrementalConverter</A>, <A HREF="../../../weka/core/converters/DatabaseConverter.html" title="interface in weka.core.converters">DatabaseConverter</A>, <A HREF="../../../weka/core/OptionHandler.html" title="interface in weka.core">OptionHandler</A></DL><P>Reads from a database. Can read a database in batch or incremental mode. In inremental mode MySQL and HSQLDB are supported. For all other DBMS set a pseudoincremental mode is used: In pseudo incremental mode the instances are read into main memory all at once and then incrementally provided to the user. For incremental loading the rows in the database table have to be ordered uniquely. The reason for this is that every time only a single row is fetched by extending the user" query by a LIMIT clause. If this extension is impossible instances will be loaded pseudoincrementally. To ensure that every row is fetched exaclty once, they have to ordered. Therefore a (primary) key is necessary.This approach is chosen, instead of using JDBC driver facilities, because the latter one differ betweeen different drivers. If you use the DatabaseSaver and save instances by generating automatically a primary key (its name is defined in DtabaseUtils), this primary key will be used for ordering but will not be part of the output. The user defined SQL query to extract the instances should not contain LIMIT and ORDER BY clauses (see -Q option). In addition, for incremental loading, you can define in the DatabaseUtils file how many distinct values a nominal attribute is allowed to have. If this number is exceeded, the column will become a string attribute. In batch mode no string attributes will be created. Available options are: -Q the query to specify which tuples to load<br> The query must have the form: SELECT *|<column-list> FROM <table> [WHERE} (default: SELECT * FROM Results0).<p> -P comma separted list of columns that are a unqiue key <br> Only needed for incremental loading, if it cannot be detected automatically<p> -I <br> Sets incremental loading<P><P><DL><DT><B>Version:</B></DT> <DD>$Revision: 1.1 $</DD><DT><B>Author:</B></DT> <DD>Stefan Mutter (mutter@cs.waikato.ac.nz)</DD><DT><B>See Also:</B><DD><A HREF="../../../weka/core/converters/Loader.html" title="interface in weka.core.converters"><CODE>Loader</CODE></A>, <A HREF="../../../serialized-form.html#weka.core.converters.DatabaseLoader">Serialized Form</A></DL><HR><P><!-- ======== NESTED CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><A NAME="field_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Field Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#BOOL">BOOL</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#BYTE">BYTE</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#DATE">DATE</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#DOUBLE">DOUBLE</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#FLOAT">FLOAT</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#INTEGER">INTEGER</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#LONG">LONG</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#SHORT">SHORT</A></B></CODE><BR> </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#STRING">STRING</A></B></CODE><BR> </TD></TR></TABLE> <!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#DatabaseLoader()">DatabaseLoader</A></B>()</CODE><BR> Constructor</TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#connectToDatabase()">connectToDatabase</A></B>()</CODE><BR> Opens a connection to the database</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../../weka/core/Instances.html" title="class in weka.core">Instances</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getDataSet()">getDataSet</A></B>()</CODE><BR> Return the full data set in batch mode (header and all intances at once).</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getKeys()">getKeys</A></B>()</CODE><BR> Gets the key columns' name</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../../weka/core/Instance.html" title="class in weka.core">Instance</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getNextInstance()">getNextInstance</A></B>()</CODE><BR> Read the data set incrementally---get the next instance in the data set or returns null if there are no more instances to get.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String[]</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getOptions()">getOptions</A></B>()</CODE><BR> Gets the setting</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getQuery()">getQuery</A></B>()</CODE><BR> Gets the query to execute against the database</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../../weka/core/Instances.html" title="class in weka.core">Instances</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getStructure()">getStructure</A></B>()</CODE><BR> Determines and returns (if possible) the structure (internally the header) of the data set as an empty set of instances.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getUrl()">getUrl</A></B>()</CODE><BR> Gets the URL</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#getUser()">getUser</A></B>()</CODE><BR> Gets the user name</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#globalInfo()">globalInfo</A></B>()</CODE><BR> Returns a string describing this Loader</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#keysTipText()">keysTipText</A></B>()</CODE><BR> the tip text for this property</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.util.Enumeration</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#listOptions()">listOptions</A></B>()</CODE><BR> Lists the available options</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#main(java.lang.String[])">main</A></B>(java.lang.String[] options)</CODE><BR> Main method.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#passwordTipText()">passwordTipText</A></B>()</CODE><BR> the tip text for this property</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#queryTipText()">queryTipText</A></B>()</CODE><BR> the tip text for this property</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#reset()">reset</A></B>()</CODE><BR> Resets the Loader ready to read a new data set</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#resetStructure()">resetStructure</A></B>()</CODE><BR> Resets the structure of instances</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#setKeys(java.lang.String)">setKeys</A></B>(java.lang.String keys)</CODE><BR> Sets the key columns of a database table</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../weka/core/converters/DatabaseLoader.html#setOptions(java.lang.String[])">setOptions</A></B>(java.lang.String[] options)</CODE>⌨️ 快捷键说明
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