6.0.0-git
2021-10-27

Diff for Project/Rdo between 1 and 2

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+ Rdo - Rampage Data Objects



Rdo is a !DataMapper implementation for Horde, using domain/entity objects combined with Mapper objects that handle the actual data manipulation.



++ Bugs







++


++ People



ChuckHagenbuch

ChuckHagenbuch is the primary author of Rdo.



++ Description



+++ Notes on database abstraction



MDB2_Schema xslt:

http://cvs.php.net/viewvc.cgi/pear/MDB2_Schema/docs/





regarding
regarding charset support, here's a topic summary:



http://www.alberton.info/dbms_charset_settings_explained.html

http://oss.backendmedia.com/MDB2/CharacterSet

http://pear.php.net/bugs/4666



In MDB2, most drivers basically resort to a "SET NAMES" query.

The MySQL driver initially used the "SET character_set_client"

statement, but I changed it after some complaints, for it

was not effective for most setups.






Another thing that bothers me, is the fact that

there isn't a single charset naming convention.



http://www.postgresql.org/docs/8.2/interactive/multibyte.html#MULTIBYTE-CHARSET-SUPPORTED

http://dev.mysql.com/doc/refman/5.0/en/charset-charsets.html

http://www.destructor.de/firebird/charsets.htm

http://www.csee.umbc.edu/help/oracle8/server.815/a67789/appa.htm#956722

http://www.csee.umbc.edu/help/oracle8/server.815/a67789/appa.htm#956722

For instance, Traditional Chinese is labelled as "BIG_5",

"BIG5" or "ZHT16BIG5", Russian as "KOI8", "KOI8R" or "CL8KOI8R",

Western European as "latin1", "ISO8859_1" or "WE8ISO8859P1"...

In the end, a common setCharset() method is kind of pointless

without a standard charset naming convention...

Should the DBAL define a set of constants for the most

common charsets, and leave the mapping to the drivers?







"LIKE"


"LIKE" case sensitivity:




> I was not thinking of SQLite. I was thinking that MySQL LIKE operator is

> case insensitive (which is what most people want) but in other databases

> LIKE is case sensitive by default.



Not sure how you did in Metabase, but in MDB2 I have the following code for this:

            switch ($operator) {

            // case insensitive

            case 'ILIKE':

                $match = $field.'LIKE ';

                break;
                break;
            // case sensitive

            case 'LIKE':

                $match = $field.'LIKE BINARY ';

                break;



Not sure if I would use "ILIKE" again, probably I would use like with an optional

attribute to flag case sensitivity.





+++ Logging what Rdo does



See "ror_logs.png" attachment.


+++ Database field sizing

When possible, make varchar fields 2**n - 1 (255, etc). Internally (MySQL), one extra byte is needed to store the length of the string. So when you add the extra byte, the length is then an even power of two. This is desirable for technical reasons. In particular, it ensures that the field will be on an even word boundary given that eight byte words are used.

Obviously, an exception is when the data in a field is inherently of a particular length. For example, NYAuthUser.UserPass contains an MD5 hash of the actual password. md5() always returns exactly 32 characters. So the field should indeed be exactly 32 characters long - and thus a CHAR instead of a VARCHAR. CHAR fields don't need the extra byte.


+++ Paging



You hardly need a library for figuring out pagination. A very simple formula tells you how many "pages" you have.

<code type="php">

$itemsPerPage = 10;

$totalRecords = 52; //Result of SELECT FOUND_ROWS()

$pages = ceil($totalRecords/$itemsPerPage);

</code>



Based on those numbers, you know you have 6 pages of data. You can then create a loop to generate the links with the proper parameter(s), however you want to format them. For example:

<code>

link.php?page=3&itemsperpage=10

</code>



Would make the following query:

<code>

SELECT * FROM table LIMIT ($_GET['page']-1)*10,10

</code>

I may be off by 1 on that. Hope that helps.

On 10/18/07, Brent Baisley <brenttech@gmail.com> wrote:

You don't need to do an extra count query. If you are using MySQL, just add SQL_CALC_FOUND_ROWS to your select query. SELECT SQL_CALC_FOUND_ROWS * FROM ...

I may be off by 1 on that. Hope that helps.



On 10/18/07, Brent Baisley <brenttech@gmail.com> wrote:



You don't need to do an extra count query. If you are using MySQL, just add SQL_CALC_FOUND_ROWS to your select query. SELECT SQL_CALC_FOUND_ROWS * FROM ...



YouYou can then run SELECT FOUND_ROWS() to get the total rows without any limits. It's still 2 queries, but the second one is essentially free.





+++ Adding backup database servers



> I'm kind of of the opinion that this sort of thing (failover) belongs on the database server, not in the app.

In our environment, the apps that we use all utilize this sort of thing for a rudimentary failover behaviour (postfix, amavisd, etc). We modified courier-authlib and dovecot to include this type of behaviour.  We can handle a complete crash of our primary r/w db server and still keep our imap/http/pop3/smtp services operational.

We have two database servers that are circular redundant -> mysql-01 and mysql-02.  mysql-01 is the primary r/w server.  If an app cannot connecto mysql-01, then I would like to to connec to to mysql-02 and process as normal.  When mysql-01 comes back online, it reads the updates from -02 and continues normal operation.  We also have a handful of r/o slave servers for the mx servers to query for user metadata.

In our environment, the apps that we use all utilize this sort of thing for a rudimentary failover behaviour (postfix, amavisd, etc). We modified courier-authlib and dovecot to include this type of behaviour.  We can handle a complete crash of our primary r/w db server and still keep our imap/http/pop3/smtp services operational.



We have two database servers that are circular redundant -> mysql-01 and mysql-02.  mysql-01 is the primary r/w server.  If an app cannot connecto mysql-01, then I would like to to connec to to mysql-02 and process as normal.  When mysql-01 comes back online, it reads the updates from -02 and continues normal operation.  We also have a handful of r/o slave servers for the mx servers to query for user metadata.



HowHow would you suggest the database server handle this instead of the app?  Obviously ifif the db server isis down, it won't bebe able to process a message to redirect the host to the next server...



Horde is the only app that we have that doesn't include some sort of failover (on connect).  I quick whipped up a patch if you think it might be usefull, otherwise we will just use it here.  I have tested it and it works sufficent for our needs.  We have had to modify the framework, horde, jonah, kronolith, and turba.  The modifications are minor to each file and I have attached them.  All changes are off of CVS HEAD.



See "Re_ _horde_ adding backup servers to mysql db driver.zip" attachment.


Horde is the only app that we have that doesn't include some sort of failover (on connect).  I quick whipped up a patch if you think it might be usefull, otherwise we will just use it here.  I have tested it and it works sufficent for our needs.  We have had to modify the framework, horde, jonah, kronolith, and turba.  The modifications are minor to each file and I have attached them.  All changes are off of CVS HEAD.

See "Re_ _horde_ adding backup servers to mysql db driver.zip" attachment.


++ Resources



http://ajaxian.com/archives/ext-scaffold-generator-plugin-for-rails

http://ajaxian.com/archives/lipsiadmin-rails-20-ext-admin

http://blog.stuartherbert.com/php/2008/05/08/what-should-an-orm-offer/

http://code.nytimes.com/projects/dbslayer

http://www.phpdoctrine.org/index.php/documentation/manual?chapter=migration

http://michaelkimsal.com/blog/gorm-goodness-in-php/

http://grails.org/GORM

http://jan.kneschke.de/2007/2/19/typesafe-objects-in-php

http://jeremy.zawodny.com/mysql/mysql-optimization.html

http://kore-nordmann.de/blog/why_active_record_sucks.html

http://code.google.com/p/pdorm/

http://phing.info/docs/guide/current/chapters/appendixes/AppendixC-OptionalTasks.html#DbDeployTask

http://pooteeweet.org/blog/0/918#m918

http://pooteeweet.org/blog/0/1083#m1083

http://sebastian-bergmann.de/archives/751-Testing-with-SQLite-In-Memory-Databases.html

http://www.blobstreaming.org/

http://www.ddataobjects.com/current/prog/

http://www.phpdoctrine.org/documentation/manual?chapter=migration

http://framework.zend.com/manual/en/zend.db.profiler.html





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