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From I D B Major <im5...@compsci.bristol.ac.uk>
Subject Re: Problem accessing two McKoi databases from Tomcat
Date Mon, 26 Jun 2006 14:18:53 GMT
Hi Brian,

many thanks for the suggestions, I'm sure I'm now close, but I'm not 
quite out of the trees yet. I have looked up the spec and followed your 
suggestion to specify the datasource and I have changed one of the 
context-params to simply dataSource. This means I now no longer get the 
same error message but instead I get an error message at the point where 
I call ShowTest (which is the context-param I changed) which has the 
root cause;

javax.servlet.ServletException: Unable to get connection, DataSource invalid: "java.sql.SQLException:
No suitable driver"

I'm not sure why this is. If you can see it please let me know.

Once again many thanks,

Iain.



Brian Buchanan wrote:

As I understand your problem, you have two JDBC Datasources setup,
jdbc/mydb and jdbc/curzon, and you are using JSTL which means to me that
your JSP pages have <sql:...> tags in them.

I think you are just missing the fact that the <sql:> tags *default* to
the JDBC connection as specified by the context param
javax.servlet.jsp.jstl.sql.dataSource.  That's only the DEFAULT value.
You can override the JDBC source in the tag:

You need the JSTL specification from here:
http://java.sun.com/products/jsp/jstl/index.jsp

and checkout page 121.

In short: specify dataSource attribute to override the default.

Finally, you should only define the value for the context-param
'javax.servlet.jsp.jstl.sql.dataSource' once in your web.xml.  It's only
setting the default for the context so having the second is only
overriding the first. (or the otherway around)

sample.jsp (untested)
----------
<%@ page language='java'%>
<%@ taglib prefix='sql' uri='http://java.sun.com/jsp/jstl/sql' %>
<%@ taglib prefix='c'   uri='http://java.sun.com/jsp/jstl/core' %>
<sql:query var='testmydb' dataSource='jdbc/mydb'>
select * from Film
</sql:query>
<sql:query var='testcurzon' dataSource='jdbc/curzon'>
select * from Film
</sql:query>
... etc.


I HTH.

._. Brian



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> -----Original Message-----
> From: I D B Major <im5033@compsci.bristol.ac.uk>
> Date: Mon, 26 Jun 2006 09:44:37 +0100
>
>   
>> Hi all,
>>
>> please can someone confirm whether I need to clarify anything in my 
>> question or take a different approach since I have had no replies and
>> am 
>> anxious to make sure I am doing all I can to seek help in the correct 
>> way. Please correct me if my approach is wrong!
>>
>> many thanks
>>
>>
>> Iain
>>
>>
>> I D B Major wrote:
>>     
>>> Hi
>>>
>>> I am a student trying to set up a project using JSP with JSTL custom 
>>> tags to provide dynamic pages to allow a web-based ticketing system 
>>> for independent cinemas. I am at the early stages of testing that I 
>>> can use the technologies. I have installed and configured Tomcat to 
>>> allow password protection to the site and I have embedded a McKoi 
>>> database which I can access and use to do insert, update and delete 
>>> queries using a test JSP page which has customised JSTL tags that are
>>> used to run the SQL query on the database.
>>>
>>> I am now trying to display data from two separate databases. I can
>>>       
>> get 
>>     
>>> each to display separately but not both at once. My issues seem to be
>>> around the details held in web.xml which are as follows;
>>>
>>>    <context-param>
>>>        <param-name>javax.servlet.jsp.jstl.sql.dataSource</param-name>
>>>        <param-value>jdbc/mydb</param-value>
>>>    </context-param>
>>>      <resource-ref>
>>>        <description>DB Connection</description>
>>>        <res-ref-name>jdbc/mydb</res-ref-name>
>>>        <res-type>javax.sql.DataSource</res-type>
>>>        <res-auth>Container</res-auth>
>>>    </resource-ref>
>>>      <context-param>
>>>        <param-name>javax.servlet.jsp.jstl.sql.dataSource</param-name>
>>>        <param-value>jdbc/curzon</param-value>
>>>    </context-param>
>>>      <resource-ref>
>>>        <description>DB Connection</description>
>>>        <res-ref-name>jdbc/curzon</res-ref-name>
>>>        <res-type>javax.sql.DataSource</res-type>
>>>        <res-auth>Container</res-auth>
>>>    </resource-ref>
>>>
>>> If I change the name of either of the <param-name> then the other
>>>       
>> will 
>>     
>>> work and allow database access to that database (ie <Resource>
>>>       
>> details 
>>     
>>> in server.xml are correctly recorded) but the one which is altered is
>>> not available so that Tomcat displays an error message to say the 
>>> table requested is not found;
>>>
>>> org.apache.jasper.JasperException: javax.servlet.jsp.JspException: 
>>>      select * from Film
>>>
>>>  : Table 'APP.Film' was not found.
>>>
>>> I have googled and googled, read the apache website in all areas I
>>>       
>> can 
>>     
>>> think of to look up and have asked my tutor for help. All without 
>>> success. I have discovered that the <param-name> given above is a 
>>> default so I tried adjusting the names (setting first one and then
>>>       
>> the 
>>     
>>> other to javax.servlet.jsp.jstl.dataSource.other or  
>>> javax.servlet.jsp.jstl..otherdataSource or other.dataSource) and even
>>> removing the <context-param> altogether but none of these work.
>>>
>>> Please can someone point me in the right direction for how to find
>>>       
>> out 
>>     
>>> what the <param-name> needs to be set to in order to allow two 
>>> databases to be accessed at once?
>>>
>>> many thanks,
>>>
>>> Iain M
>>>
>>>       


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