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<h2 class="title" style="clear: both"><a id="dpl_delete"></a>Deleting Entity Objects</h2>
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<p>
The simplest way to remove an object from your entity store
is to delete it by its primary index. For example,
using the <code class="classname">SimpleDA</code> class that we
created earlier in this document
(see <a class="xref" href="simpleda.html" title="SimpleDA.class">SimpleDA.class</a>),
you can delete the <code class="classname">SimpleEntityClass</code>
object with a primary key of <code class="literal">keyone</code> as
follows:
</p>
<pre class="programlisting">sda.pIdx.delete("keyone");</pre>
<p>
You can also delete objects by their secondary keys. When
you do this, all objects related to the secondary key are
deleted, unless the key is a foreign object.
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<p>
For example, the following deletes all
<code class="classname">SimpleEntityClass</code> with a secondary
key of <code class="literal">skeyone</code>:
</p>
<pre class="programlisting">sda.sIdx.delete("skeyone");</pre>
<p>
You can delete any single object by positioning a cursor to
that object and then calling the cursor's
<code class="methodname">delete()</code> method.
</p>
<pre class="programlisting">PrimaryIndex<String,SimpleEntityClass> pi =
store.getPrimaryIndex(String.class, SimpleEntityClass.class);
SecondaryIndex<String,String,SimpleEntityClass> si =
store.getSecondaryIndex(pi, String.class, "sKey");
EntityCursor<SimpleEntityClass> sec_cursor =
si.subIndex("skeyone").entities();
try {
SimpleEntityClass sec;
Iterator<SimpleEntityClass> i = sec_cursor.iterator();
while (sec = i.nextDup() != null) {
if (sec.getSKey() == "some value") {
i.delete();
}
}
// Always make sure the cursor is closed when we are done with it.
} finally {
sec_cursor.close(); } </pre>
<p>
Finally, if you are indexing by foreign key, then the
results of deleting the key is determined by the foreign
key constraint that you have set for the index. See
<a class="xref" href="dplindexcreate.html#foreignkey" title="Foreign Key Constraints">Foreign Key Constraints</a>
for more information.
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