Problem with DatabaseExampleSetWriter

Problem with DatabaseExampleSetWriter

Hi Ingo, Hi All,

I have a problem with the operator DatabaseExampleSetWriter. I tried an experiment where I want to "merge" (neither Join, nor Merge, nor anything else) two examplesets outside RM with raw SQL handling.

For that, I installed mySQL and WampServer on a standalone PC. I have verified access rights on a database I have created, called "travail_rapidminer". With or without password, RM does not seem to access this database properly, as I asked it to overwrite output exampleset onto it.

Here is my XML process code :


and the error box :


At last, here are my settings on database side :

And here is the dialog box that appears before the error box at running :

I precise that passwords are coherent, despite the XML experiment does not seem so on this point. Is it a bug, or did I misuse the operator ?


Re: Problem with DatabaseExampleSetWriter

Hi Jean-Charles,

hmm, I must admit that I don't have any clue right now what causes this problem. Did you try if reading from this database works well? The error occurs at a place which actually does not have anything to do which is specific to RM - it directly occurs at the place where the connection is constructed and there is no specific magic done. So I would still assume that there could be an error at the settings. Here is the relevant parts:

                <operator name="DatabaseExampleSetWriter (3)" class="DatabaseExampleSetWriter">
                    <parameter key="database_url" value="jdbc:mysql://localhost:80/travail_rapidminer"/>
                    <parameter key="overwrite_mode" value="overwrite"/>
                    <parameter key="table_name" value="table_elements"/>
                    <parameter key="username" value="root@localhost"/>

Some questions:

1. did reading from this database works with these settings?
2. port 80 is rather unusual for a database - the default for mySQL is 3306 if I am not mistaken
3. the user name root@localhost is also unusual - did you try "root" alone?

Sorry, I have no other ideas right now.


How to load processes in XML from the forum into RapidMiner: Read this!

Re: Problem with DatabaseExampleSetWriter

Hi Ingo, Hi All,

Sorry for the late reply  Smiley Tongue
I may try with a different port, 3306 instead of 80, you seem to be right...