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<h1 class="topictitle1">Goals and directions for a distributed relational database</h1>
<div><p>The third step in your analysis is to assess your short-term and
long-term goals.</p>
<div class="section"><p>SQL is the standard IBM<sup>®</sup> database language. If your goals and
directions include portability or remote data access on unlike systems, you
should use distributed relational database on the <span class="keyword">iSeries™ server</span>.</p>
</div>
<div class="section"><p>The distributed database function of distributed unit of work,
as well as the additional data copying function provided by <span>DataPropagator™ for iSeries,
V8.1</span>, broadens the range of activities you can perform on the <span class="keyword">iSeries server</span>. However, if your distributed
database application requires a function that is not currently available on
the <span class="keyword">iSeries server</span>, other options
are available until the function is made available on the operating system.
For example, you can do one of the following things: </p>
<ul><li>Provide the needed function yourself.</li>
<li>Stage your plans for distributed relational database to allow for the
new function to become available.</li>
<li>Reassess your goals and requirements to see if you can satisfy them with
a currently available or announced function. Some alternative solutions are
listed in the following table. These alternatives can be used to supplement
or replace available function.</li>
</ul>
<div class="tablenoborder"><a name="rbal1goalsanddir__rbal1alter"><!-- --></a><table cellpadding="4" cellspacing="0" summary="" id="rbal1goalsanddir__rbal1alter" width="100%" frame="border" border="1" rules="all"><caption>Table 1. Alternative
solutions to distributed relational database</caption><thead align="left"><tr><th align="left" valign="bottom" width="19.618055555555554%" id="d0e61">Solution</th>
<th align="left" valign="bottom" width="30.381944444444443%" id="d0e63">Description</th>
<th align="left" valign="bottom" width="27.95138888888889%" id="d0e65">Advantages</th>
<th align="left" valign="bottom" width="22.04861111111111%" id="d0e67">Disadvantages</th>
</tr>
</thead>
<tbody><tr><td align="left" valign="top" width="19.618055555555554%" headers="d0e61 ">Distributed Data Management (DDM)</td>
<td align="left" valign="top" width="30.381944444444443%" headers="d0e63 ">A function of the operating system that allows
an application program or user on one system to use database files stored
on a remote system. The system must be connected by a communications network,
and the remote system must also use DDM.</td>
<td align="left" valign="top" width="27.95138888888889%" headers="d0e65 "> <ul><li>For simple read and update accesses, the performance is better than for
SQL.</li>
<li>Existing applications do not need to be rewritten.</li>
<li>Can be used to access S/38, S/36, and CICS<sup>®</sup>.</li>
</ul>
</td>
<td align="left" valign="top" width="22.04861111111111%" headers="d0e67 "> <ul><li>SQL is more efficient for complex functions.</li>
<li>Might not be able to access other distributed relational database platforms.</li>
<li>Does not perform CCSID and numeric data conversions.</li>
</ul>
</td>
</tr>
<tr><td align="left" valign="top" width="19.618055555555554%" headers="d0e61 ">Intersystem Communications Function/Common
Programming Interface (ICF/CPI Communications)</td>
<td align="left" valign="top" width="30.381944444444443%" headers="d0e63 ">ICF is a function of the operating system
that allows a program to communicate interactively with another program or
system. CPI Communications is a call-level interface that provides a consistent
application interface for applications that use program-to-program communications.
These interfaces make use of SNA's logical unit (LU) 6.2 architecture to establish
a conversation with a program on a remote system, to send and receive data,
to exchange control information, to end a conversation, and to notify a partner
program of errors.</td>
<td align="left" valign="top" width="27.95138888888889%" headers="d0e65 "> <ul><li>Allows you to customize your application to meet your needs.</li>
<li>Can provide better performance.</li>
</ul>
</td>
<td align="left" valign="top" width="22.04861111111111%" headers="d0e67 ">Compared to distributed relational database
and DDM, a more complicated program is needed to support communications and
data conversion requirements.</td>
</tr>
<tr><td align="left" valign="top" width="19.618055555555554%" headers="d0e61 ">Display station pass-through</td>
<td align="left" valign="top" width="30.381944444444443%" headers="d0e63 ">A communications function that allows a user
to sign on to one <span class="keyword">iSeries server</span> from
another <span class="keyword">iSeries server</span> and use that
server's programs and data.</td>
<td align="left" valign="top" width="27.95138888888889%" headers="d0e65 "> <ul><li>Applications and data on remote systems are accessible from local systems.</li>
<li>Allows for quick access when data is volatile and a large amount of data
on one server is needed by users on several servers.</li>
</ul>
</td>
<td align="left" valign="top" width="22.04861111111111%" headers="d0e67 ">Response time on screen updates is slower
than locally attached devices.</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="section"><p>A distributed relational database usually evolves from simple
to complex as business needs change and new products are made available. Remember
to consider this when analyzing your needs and expectations.</p>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rbal1idyourneeds.htm" title="Consider these items when analyzing your needs and expectations of a distributed relational database.">Identify your needs and expectations for a distributed relational database</a></div>
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