Loading ...
Sorry, an error occurred while loading the content.

RE: [metabase-dev] create tables

Expand Messages
  • Lukas Smith
    ... gather ... unsure ... and so I have done :-) http://www.psiweb-guide.aa.psiweb.com/MySQL/manual/manual_Performance.ht ml#Row_format so it really seems to
    Message 1 of 9 , Dec 3, 2001
    • 0 Attachment
      > Actually I will make some more research on that. But from what I
      gather
      > if you have and index on a table with fixed column lengths it can
      > quickly skip around in it because the DB knows the length of each row.
      > But I must admit after writing that email I was becoming sort of
      unsure
      > myself where I got this (maybe it was in some university course where
      > they talk about theory and not reality :-) )
      >

      and so I have done :-)

      http://www.psiweb-guide.aa.psiweb.com/MySQL/manual/manual_Performance.ht
      ml#Row_format

      so it really seems to only matter when all tables are of fixed length.

      Best regards,
      Lukas Smith
      smith@...
      _______________________________
      DybNet Internet Solutions GbR
      Alt Moabit 89
      10559 Berlin
      Tel. : +49 30 83 22 50 00
      Fax : +49 30 83 22 50 07
      www.dybnet.de info@...
      _______________________________

      > -----Original Message-----
      > From: Lukas Smith [mailto:smith@...]
      > Sent: Friday, November 30, 2001 12:44 PM
      > To: metabase-dev@yahoogroups.com
      > Subject: RE: [metabase-dev] create tables
      >
      > Best regards,
      > Lukas Smith
      > smith@...
      > _______________________________
      > DybNet Internet Solutions GbR
      > Alt Moabit 89
      > 10559 Berlin
      > Tel. : +49 30 83 22 50 00
      > Fax : +49 30 83 22 50 07
      > www.dybnet.de info@...
      > _______________________________
      >
      > > -----Original Message-----
      > > From: mlemos@... [mailto:mlemos@...] On
      > Behalf
      > > Of Manuel Lemos
      > > Sent: Friday, November 30, 2001 7:03 AM
      > > To: metabase-dev@yahoogroups.com
      > > Subject: Re: [metabase-dev] create tables
      > >
      > > Hello,
      > >
      > > Lukas Smith wrote:
      > > >
      > > > Sorry ... will switch to text emails
      > > > Primary Keys:
      > > > Aha ... is this in the documentation?
      > > > Well I did not test the functions, I just looked at the API/docs.
      > > > Its probably under individual RDBMS limitations.
      > >
      > > No, primary keys will be supported explicitly soon or later, so I
      > > decided to not mention that.
      > >
      > >
      > > > No actually I rarely use char.
      > > > I think we currently have one instance. But actually I do the
      > padding
      > > > myself in that case. But I was thinking of using char's in my
      > > > searchengine.
      > > >
      > > > I wanted to build the searchengine with separate tables based on
      > word
      > > > length:
      > > > 4 letter words
      > > > 5
      > > > 6
      > > > 7
      > > > 8
      > > > 9
      > > > 10
      > > > 11+
      > > >
      > > > for example
      > > > this would be mainly for performance reasons
      > > > Then again I was planning on using a checksum in the 11+ table in
      > order
      > > > to make all of those of the same length as well. Again for
      > performance
      > > > reasons.
      > > > Since a char is always the same length it can speed up searches
      > quite a
      > > > bit.
      > >
      > > Are you sure about that? I thought it would not make a difference.
      > >
      > >
      > >
      > > > In terms of the API.
      > > > I am also one of those people that would prefer a different API.
      > > > So would you be ok if we provide a wrapper for metabase instead?
      > >
      > > As I mentioned, it would be convinient if it would be viable to wrap
      > > Metabase around PEAR-DB API.
      > >
      > >
      > > > Obviously it would not be professional to just drop all those
      users
      > of
      > > > metabase. So in either way we will have to provide a migration
      path
      > for
      > > > both sides.
      > >
      > > Yes, Metabase can carry one having the current API and an enhanced
      > > PEAR-DB like API and everybody would be happy, don't you think?
      > >
      > > Regards,
      > > Manuel Lemos
      > >
      > > ------------------------ Yahoo! Groups Sponsor
      > >
      > > To Unsubscribe, send a blank message to: metabase-dev-
      > > unsubscribe@...
      > > Need other Metabase drivers?
      http://www.egroups.com/surveys/metabase-
      > > dev?id=263873
      > > Latest beta version: http://www.egroups.com/files/metabase-dev
      > > Vote on Metabase: http://www.zend.com/apps.php?id=122&single=1
      > >
      > >
      > > Your use of Yahoo! Groups is subject to
      > http://docs.yahoo.com/info/terms/
      > >
      >
      >
      >
      > ------------------------ Yahoo! Groups Sponsor
      >
      > To Unsubscribe, send a blank message to: metabase-dev-
      > unsubscribe@...
      > Need other Metabase drivers? http://www.egroups.com/surveys/metabase-
      > dev?id=263873
      > Latest beta version: http://www.egroups.com/files/metabase-dev
      > Vote on Metabase: http://www.zend.com/apps.php?id=122&single=1
      >
      >
      > Your use of Yahoo! Groups is subject to
      http://docs.yahoo.com/info/terms/
      >
    • Manuel Lemos
      Hello, ... Ok, I was not aware. Anyway, it seems that MySQL does not support real CHAR and VARCHAR fields as it strips all trailing spaces, and it is not only
      Message 2 of 9 , Dec 3, 2001
      • 0 Attachment
        Hello,

        Lukas Smith wrote:
        >
        > > Actually I will make some more research on that. But from what I
        > gather
        > > if you have and index on a table with fixed column lengths it can
        > > quickly skip around in it because the DB knows the length of each row.
        > > But I must admit after writing that email I was becoming sort of
        > unsure
        > > myself where I got this (maybe it was in some university course where
        > > they talk about theory and not reality :-) )
        > >
        >
        > and so I have done :-)
        >
        > http://www.psiweb-guide.aa.psiweb.com/MySQL/manual/manual_Performance.ht
        > ml#Row_format
        >
        > so it really seems to only matter when all tables are of fixed length.

        Ok, I was not aware. Anyway, it seems that MySQL does not support real
        CHAR and VARCHAR fields as it strips all trailing spaces, and it is not
        only it fetches data. I tried, inserting data into tables with char and
        another with varchar. MySQL always strings trailing spaces. Selecting
        fields length always return the length of the fields stripped from
        trailing spaces. So, MySQL is not ANSI conformant because it strips
        spaces whether you want them or not, and also it does not pad CHAR
        fields with spaces as the standard defines.

        Anyway, I may add support for a <fixed>1</fixed> tag to field properties
        in the database schema, but I need to document this MySQL uncompliance
        that may lead to non-portable software if the space padding is important
        for applications. I may add a work around in MySQL driver to pad results
        of selected query fields, but that won't solve the problem completely.

        I wish MySQL programmers had been more careful with this. It is like
        that Oracle annoyance of storing NULLs when you pass an empty string to
        a VARCHAR field.

        Regards,
        Manuel Lemos
      Your message has been successfully submitted and would be delivered to recipients shortly.