migrating from db2-dds to db2-sql

Hi there,<br />
<br />
What are the disavantages and advantages with the migration from a native bs2
dds on iseries to  sql db2? The performance is better with sql db2?<br />
<br />
Thanks<br />
<br />

They (pretty much) produce the same objects.<br />
<br />
There are a few things that you can accomplish with SQL-created objects that you
can't do with DDS-created objects.<br />
<br />
But, to be fair, there are a few things you can do with DDS-created objects that
you can't do with SQL-created objects. (like sorted, select/omit LF's)<br
/>
<br />
The primary advantage that I can see with SQL-created objects is that it's
commonly understood by all database developers, and learning how to use SQL's
DDL makes you much more marketable (within iSeries and outside of
iSeries).<br />
<br />
Additionally, I find that I can accomplish the same thing significantly faster
in SQL (although that may be due to the fact that I've been using it almost
exclusively for almost 10 years).<br />
<br />
Lastly, SQL seems to be the direction that IBM is heading, so you'll see less
and less improvement in DDS and more improvement in SQL.<br />
<br />
Just my two cents.<br />
<br />
<ul class="jive-dash">
<li>
<ul class="jive-dash">
<li>Dave</li>
</ul>
</li>
</ul>

   There are many development advantages to using SQL over non-SQL; that 
is where the biggest benefits can be experienced.  Moving from DDS [Data 
Definition Specifications] to SQL DDL [Data Definition Language] in the 
DB2 for i5/OS gains the ability to define Referential Integrity directly 
into the TABLE, better performing read access to TABLE, enhanced INDEX 
with EVI [Encoded Vector Index], DDL under isolation, SMP [Symmetric 
Multi-Processing] capability, better data integrity for [per validation 
of] data inserted into a TABLE, more data types including User Defined 
Types, and more.

   IMO starting to use SQL, both DDL and DML [Data Manipulation 
Language] is where the best benefits and results can be found.  After 
the benefits and any learning from corrected pitfalls have been 
experienced, only then consider entirely changing [versus only extending 
or enhancing] existing applications with SQL.  To be clear, simply 
switching from DDS to SQL DDL will lead to [possibly unexpected] 
difficulties due to the differences.  Rarely will planning for such a 
change account for everything.  I think my comments in the following 
thread are worth reviewing:
   www.ibm.com/developerworks/forums/message.jspa?messageID=13917410

   Additionally, switching from ISAM [Indexed Sequential Access Method] 
style database files directly to SQL without designing for SQL access 
will likely have programmers failing to break from the RLA [Row Level 
Access] mentality, and ability to achieve great performance with SQL 
access will be impacted.

   A couple searches [the first finds above link] and a couple links 
from those searches, that provide some more discussion and comments:

   http://www.google.com/search?num=50&hl=en&q=crpence+sql+dds+ddl
   http://www.google.com/search?num=50&hl=en&q=cruikshank+sql+dds+ddl
   www.ibm.com/servers/eserver/iseries/db2/pdf/Performance_DDS_SQL.pdf
   www.redbooks.ibm.com/abstracts/sg246393.html?Open

Regards, Chuck
-- 
  All comments provided "as is" with no warranties of any kind 
whatsoever and may not represent positions, strategies, nor views of my 
employer

leonardo.vivar@braining.ws wrote:
> What are the disadvantages and advantages with the migration from a
> native DB2 DDS on iSeries to SQL DB2? The performance is better with