Most of us using databases or doing data minings are not aware of SQL-92 specification seemingly these days.

SQL-92 specifiaction is the SQL database query language standard.

Oracle,mysql postgresql,mssql and DB2 - most widely recognized SQL database programs - are all closely related to SQL-92 specification for the use of query nevertheless how they implemented SQL-92 specification features inside in the program.

Implementation of SQL-92 specification features are applied in the order of Oracle, postgresql and mysql. These databases might have specific database query language dedicated to its own feature due to its systematic features of the program or/and traditions or/and add-on for the convenience of the users.

As long as you're aware of the figures implemented in specific database programs, you can write the program using query languages that can be used for other programs.

For instance, sub-query was not implemented in mysql as of version three line. When you want to write the program which can run in postgresql and oracle version at the time of mysql version three lines, you should be aware of the figure that sub-query is not implemented for mysql at the time as well as other features that might prevent the program not to run by posgresql,Oracle and etc.

This is the SQL-92 specification although it is only Second Informal Review Draft and the hypher text link toward this version is http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt.


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Have a nice day!

My blog : silverbluewater.blogspot.com

This post has been edited by Silver Bluewater: Jun 5 2007, 01:21 PM

Thanks for the info and the link.

Best regards,

I'm not so good with databases.
I can though work my way around a mysql database for my site.
As long as I can do that im happy.

My pleasure.



Ic.


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Have a nice day!

My blog : silverbluewater.blogspot.com

This post has been edited by Silver Bluewater: Jun 12 2007, 03:51 AM

So can somebody please elaborate on what this means?

I get that this is some sort of standards thing, like the html, css, etc... but I am not sure what we are supposed to do with this, or what is supposed to be taken from this.

This simply seems to be a reminder of the need of standards. If you don't know how it works but you know it's standard, have a look at the standards.
If you want to learn how to create a program based on database usage, and want to be independant from the database provider - using Oracle for big professional databases using a very expensive RDBMs or mysql for a small home database using free software - you have to learn how each one confirms to standards, and then you can use standard sentences (select * from mytable where myfield="myself"), and avoid unexisting features, or even use the standard features of a given RDBMS in order to boost your queries.
So, what is supposed to be taken from this ? Simply the link to the document you must keep in mind, as well as a general philosophy in the way you design your own work ; or the way you have to check that you work you pay for is really done.
Regards
Yordan

I think the answer is provided in a good descriptive terms by yordan. : D



I checked the post today and found the answer is already given to the question. Thank you for the good answer, yordan. I think your answer would be also the answers for some other users too. : D


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Short tip and news of the trend of famous database systems which might be helpful for
some of the users to understand the topic here: Postgresql,Oracle and mysql .

Oracle is known for its good reliability and so it has been used for very big professional
environments while mysql has been used for small environment. Postgresql has been used
as something in between of Oracle and mysql with its transaction(data-securing figure used
for database systems in a very simple term) figure. Transaction is quite recently supported
by mysql. Oracle has been supporting transaction features the most among these three
major-line database systems as well as known for its fast standard implementing.
Transaction is very important feature where the environment is sensitive over data-loses.
Around the version three line of mysql, transaction in real terms was only supported by
Oracle. Mysql is recently used for big database environment with its marketing after the
several use of mysql for a big database was found.

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Have a nice day!

My blog : silverbluewater.blogspot.com

This post has been edited by Silver Bluewater: Jul 24 2007, 02:39 PM

You're welcome. I'm very happy having been able to be helpful. Have a long life with sql databases !