RE: [Classifier4j-devel] Training and Classifying

[Neil G. <np...@nt...>]

Hi Nick,

> Is PostgreSQL case sensitive with respect to table names?

PostgreSQL is not case-sensitive - I have tested this.

> If that doesn't help, can please send the result set returned from the
> following code:
> 
> DatabaseMetaData dbm = con.getMetaData();
> ResultSet rs = dbm.getTables(null, null, "word_probability", null);

I'm not too sure what you mean when you say to "send the result set" to
you.
What method should I call on the ResultSet.

When I do:
	ResultSetMetaData rM = rs.getMetaData();
	String name = rM.getColumnName(2);

The value of name is "table_schem".  Shouldn't it be one of the names of
the columns in the word_probability table??

Regards

Neil


> -----Original Message-----
> From: cla...@li...
[mailto:classifier4j-
> dev...@li...] On Behalf Of Nick Lothian
> Sent: 18 May 2004 12:51
> To: cla...@li...
> Subject: Re: [Classifier4j-devel] Training and Classifying
> 
> Neil Gandhi wrote:
> 
> >Hi Nick,
> >
> >Thanks for the reply, however there is still a problem.
> >
> >The following outlines how I am trying to access the data I have
trained
> >in the "word_probability" table.  I wish to classify the String
> >'contents' against the data in the "word_probability" table:
> >
> >	DriverMangerJDBCConnectionManager cm = new
> >DriverMangerJDBCConnectionManager(connString, user, pw);
> >
> >	JDBCWordsDataSource wds = new JDBCWordsDataSource(cm);
> >
> >	ITokenizer tokenizer = new DefaultTokenizer();
> >
> >	IClassifier classifier = new BayesianClassifier(wds, tokenizer);
> >
> >	classifier.classify(contents);
> >
> >
> >I get a system error message saying:
> >net.sf.classifier4J.bayesian.WordsDataSourceException: Problem
creating
> >table
> >
> >and
> >
> >Caused by: java.sql.SQLException: ERROR:  Relation 'word_probability'
> >already exists
> >
> >It seems as if the JDBCWordsDataSource constructor is always trying
to
> >create a table, when I just want to be able to read from the existing
> >table!
> >
> >I am using a Postgres SQL database.
> >
> >I would very much appreciate you providing some code which enables me
to
> >read from the "word_probability" table and then use the standard
methods
> >to classify an unknown string.
> >
> >
> >
> 
> The code you have is exactly correct.
> 
> As previously noted, Classifier4J has been tested with MySQL & HSQLDB.
> PostgreSQL _should_ work fine with it, provided the JDBC driver
supports
> the database metadata functionality correctly.
> 
> Is PostgreSQL case sensitive with respect to table names? If so there
> was a bug we fixed after the 0.5 release that may effect you. Get the
> latest version from CVS, (or do the change yourself: see
>
<http://cvs.sourceforge.net/viewcvs.py/classifier4j/Classifier4J/src/jav
a/
>
net/sf/classifier4J/bayesian/JDBCWordsDataSource.java?r1=1.13&r2=1.14>)
> 
> If that doesn't help, can please send the result set returned from the
> following code:
> 
> DatabaseMetaData dbm = con.getMetaData();
> ResultSet rs = dbm.getTables(null, null, "word_probability", null);
> 
> Nick
> 
> 
> 
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