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Re: Re: [xml-dbms] Re: roadmap & java 1.4

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  • Tim
    Hi Ron, I looked in the code for getting the meta data for the connection and it returns 1 as the max statements per conncetion for the Informix JDBC Driver,
    Message 1 of 8 , Aug 1, 2002
      Hi Ron,

      I looked in the code for getting the meta data for the connection and it returns 1 as the max statements per conncetion for the Informix JDBC Driver, to test things out I changed this to 10, and ran the program. It completed successfully and returned an XML document which I was able to put on my MQSeries queue. If the driver seems to work with more than one statement per connection why would it return 1 as its max. Are there hidden dangers in what I have done (Apart from it being a horrible hack).

      Thanks for your help.

      Tim
      >
      > From: Ronald Bourret <rpbourret@...>
      > Date: Wed, 31 Jul 2002 04:00:51 -0700
      > To: xml-dbms@yahoogroups.com
      > Subject: Re: [xml-dbms] Re: roadmap & java 1.4
      >
      >


      [Non-text portions of this message have been removed]
    • Ronald Bourret
      This looks like a driver bug. These are fairly common in implementations of the DatabaseMetaData class, presumably since the docs are vague. You might want to
      Message 2 of 8 , Aug 1, 2002
        This looks like a driver bug. These are fairly common in implementations
        of the DatabaseMetaData class, presumably since the docs are vague.

        You might want to check the Informix documentation and see if there are
        any restrictions on the number of result sets you can have open on a
        single connection (this is what max active statements really means). If
        there are no restrictions, then change the return value to 0, which
        means "no restrictions".

        While I make no guarantees, I can't think of any dangerous problems this
        can cause. If there really is a limit, the code will simply hit it and
        throw an exception.

        -- Ron

        Tim wrote:
        >
        > Hi Ron,
        >
        > I looked in the code for getting the meta data for the connection and it returns 1 as the max statements per conncetion for the Informix JDBC Driver, to test things out I changed this to 10, and ran the program. It completed successfully and returned an XML document which I was able to put on my MQSeries queue. If the driver seems to work with more than one statement per connection why would it return 1 as its max. Are there hidden dangers in what I have done (Apart from it being a horrible hack).
      • xxx_oneill
        Hi Ron, Thanks again, I think I will go this route as I need this finished in a week or two and don t really want to lose the functionality that xml-dbms
        Message 3 of 8 , Aug 1, 2002
          Hi Ron,

          Thanks again, I think I will go this route as I need this finished in
          a week or two and don't really want to lose the functionality that
          xml-dbms provides. The DB is being migrated to Oracle in the new year
          so these problems will go away then anyway.

          Regards,

          Tim

          --- In xml-dbms@y..., Ronald Bourret <rpbourret@r...> wrote:
          > This looks like a driver bug. These are fairly common in
          implementations
          > of the DatabaseMetaData class, presumably since the docs are vague.
          >
          > You might want to check the Informix documentation and see if there
          are
          > any restrictions on the number of result sets you can have open on a
          > single connection (this is what max active statements really
          means). If
          > there are no restrictions, then change the return value to 0, which
          > means "no restrictions".
          >
          > While I make no guarantees, I can't think of any dangerous problems
          this
          > can cause. If there really is a limit, the code will simply hit it
          and
          > throw an exception.
          >
          > -- Ron
          >
          > Tim wrote:
          > >
          > > Hi Ron,
          > >
          > > I looked in the code for getting the meta data for the connection
          and it returns 1 as the max statements per conncetion for the
          Informix JDBC Driver, to test things out I changed this to 10, and
          ran the program. It completed successfully and returned an XML
          document which I was able to put on my MQSeries queue. If the driver
          seems to work with more than one statement per connection why would
          it return 1 as its max. Are there hidden dangers in what I have done
          (Apart from it being a horrible hack).
        • Ronald Bourret
          One last comment is that you can test this by creating a series of nested tables: t1 (t1_pk, t1_data) t2 (t2_pk, t1_fk, t2_data) t3 (t3_pk, t2_fk, t3_data) ...
          Message 4 of 8 , Aug 1, 2002
            One last comment is that you can test this by creating a series of
            nested tables:

            t1 (t1_pk, t1_data)
            t2 (t2_pk, t1_fk, t2_data)
            t3 (t3_pk, t2_fk, t3_data)
            ...

            Map these so that you get the following XML document:

            <t1>
            <data>xxx</data>
            <t2>
            <data>xxx</data>
            <t3>
            <data>xxx</data>
            ...
            </t3>
            </t2>
            </t1>

            Since XML-DBMS opens one result set per nesting level when retrieving
            data, you can easily test the maximum number of "active statements". As
            long as this number is greater than or equal to the maximum depth of
            your production documents, you won't hit any troubles in your production
            system.

            -- Ron

            xxx_oneill wrote:
            >
            > Hi Ron,
            >
            > Thanks again, I think I will go this route as I need this finished in
            > a week or two and don't really want to lose the functionality that
            > xml-dbms provides. The DB is being migrated to Oracle in the new year
            > so these problems will go away then anyway.
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