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<h1 class="topictitle1">Comparing Binary radix indexes and Encoded vector indexes</h1>
<div><p>DB2<sup>®</sup> UDB
for iSeries™ makes
indexes a powerful tool. </p>
<p>The following table summarizes some of the differences between binary radix
indexes and encoded vector indexes: </p>
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="border" border="1" rules="all"><caption>Table 1. Comparison of radix and evi indexes</caption><thead align="left"><tr valign="bottom"><th valign="bottom" id="d0e33">&nbsp;</th>
<th valign="bottom" id="d0e34">Binary Radix Indexes </th>
<th valign="bottom" id="d0e36">Encoded Vector Indexes</th>
</tr>
</thead>
<tbody><tr><td valign="top" headers="d0e33 ">Basic data structure</td>
<td valign="top" headers="d0e34 ">A wide, flat tree</td>
<td valign="top" headers="d0e36 ">A Symbol Table and a vector</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Interface for creating</td>
<td valign="top" headers="d0e34 ">Command, SQL, iSeries Navigator</td>
<td valign="top" headers="d0e36 ">SQL, iSeries Navigator</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Can be created in parallel</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">Yes</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Can be maintained in parallel</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">Yes</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Used for statistics</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">Yes</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Used for selection</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">Yes, via dynamic bitmaps or RRN list</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Used for joining</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">Yes (in conjunction with a hash table) </td>
</tr>
<tr><td valign="top" headers="d0e33 ">Used for grouping</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">Yes</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Used for ordering</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">No</td>
</tr>
<tr><td valign="top" headers="d0e33 ">Used to enforce unique Referential Integrity constraints</td>
<td valign="top" headers="d0e34 ">Yes</td>
<td valign="top" headers="d0e36 ">No</td>
</tr>
</tbody>
</table>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="efindex.htm" title="DB2 Universal Database for iSeries provides two basic means for accessing tables: a table scan and an index-based retrieval. Index-based retrieval is typically more efficient than table scan when less than 20% of the table rows are selected.">Creating an index strategy</a></div>
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