src/main/site/content/docs/3.0/queries-stored-in-datamap.html

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title: Queries Stored in DataMap
url: /docs/3.0/queries-stored-in-datamap.html
layout: docs_legacy
---

	
<P>To facilitate reuse of queries users can assign symbolic names to them and store such named queries in a DataMap. Normally this is done by <A href="modeling-queries.html" title="Modeling Queries">creating a query in CayenneModeler</A>. Storing queries in a DataMap reduces the amount of code and speeds up query creation process.</P>

<P>This example shows how to get a shared instance of a stored query, and use it as a template for customized query.</P>
<DIV class="code panel" style="border-width: 1px;"><DIV class="codeContent panelContent">
<PRE class="code-java">DataContext context = ... <SPAN class="code-comment">// assume <SPAN class="code-keyword">this</SPAN> exists
</SPAN>
<SPAN class="code-comment">// 1. lookup prototype
</SPAN>
<SPAN class="code-comment">// note a <SPAN class="code-keyword">cast</SPAN> to SelectQuery... Generally DataMap can store any type of queries
</SPAN>SelectQuery prototype = (SelectQuery) context.getEntityResolver().lookupQuery(<SPAN class="code-quote">&quot;MySelect&quot;</SPAN>);

<SPAN class="code-comment">// 2. customize query
</SPAN>Map params = <SPAN class="code-keyword">new</SPAN> HashMap();
params.put(<SPAN class="code-quote">&quot;aname&quot;</SPAN>, <SPAN class="code-quote">&quot;Monet&quot;</SPAN>);
SelectQuery query = prototype.queryWithParameters(params);

<SPAN class="code-comment">// 3. execute query
</SPAN>List objects = context.performQuery(query);
</PRE>
</DIV></DIV>
<P>DataContext supports running a named query with preset parameters directly:</P>
<DIV class="code panel" style="border-width: 1px;"><DIV class="codeContent panelContent">
<PRE class="code-java">DataContext context = ... <SPAN class="code-comment">// assume <SPAN class="code-keyword">this</SPAN> exists
</SPAN>
<SPAN class="code-comment">// <SPAN class="code-quote">&quot;<SPAN class="code-keyword">false</SPAN>&quot;</SPAN> indicates that a cached result should be used <SPAN class="code-keyword">if</SPAN> available 
</SPAN>List objects = context.performQuery(<SPAN class="code-quote">&quot;MySelect&quot;</SPAN>, <SPAN class="code-keyword">false</SPAN>);
</PRE>
</DIV></DIV>