glib-relations-and-tuples.html

glid编写实例

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<a name="id3199919"></a><h3>
<a name="g-relation-count"></a>g_relation_count ()</h3>
<a class="indexterm" name="id3199929"></a><pre class="programlisting"><a href="glib-Basic-Types.html#gint">gint</a>        g_relation_count                (<a href="glib-Relations-and-Tuples.html#GRelation">GRelation</a> *relation,
                                             <a href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> key,
                                             <a href="glib-Basic-Types.html#gint">gint</a> field);</pre>
<p>
Returns the number of tuples in a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a> that have the given value
in the given field.
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<span class="term"><em class="parameter"><code>relation</code></em>&#160;:</span></td>
<td>a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>.
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<span class="term"><em class="parameter"><code>key</code></em>&#160;:</span></td>
<td>the value to compare with.
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<span class="term"><em class="parameter"><code>field</code></em>&#160;:</span></td>
<td>the field of each record to match.
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<span class="term"><span class="emphasis"><em>Returns</em></span>&#160;:</span></td>
<td>the number of matches.


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<a name="id3200046"></a><h3>
<a name="g-relation-select"></a>g_relation_select ()</h3>
<a class="indexterm" name="id3200058"></a><pre class="programlisting"><a href="glib-Relations-and-Tuples.html#GTuples">GTuples</a>*    g_relation_select               (<a href="glib-Relations-and-Tuples.html#GRelation">GRelation</a> *relation,
                                             <a href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> key,
                                             <a href="glib-Basic-Types.html#gint">gint</a> field);</pre>
<p>
Returns all of the tuples which have the given key in the given field.
Use <a href="glib-Relations-and-Tuples.html#g-tuples-index"><code class="function">g_tuples_index()</code></a> to access the returned records.
The returned records should be freed with <a href="glib-Relations-and-Tuples.html#g-tuples-destroy"><code class="function">g_tuples_destroy()</code></a>.
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<span class="term"><em class="parameter"><code>relation</code></em>&#160;:</span></td>
<td>a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>.
</td>
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<span class="term"><em class="parameter"><code>key</code></em>&#160;:</span></td>
<td>the value to compare with.
</td>
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<span class="term"><em class="parameter"><code>field</code></em>&#160;:</span></td>
<td>the field of each record to match.
</td>
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<span class="term"><span class="emphasis"><em>Returns</em></span>&#160;:</span></td>
<td>the records (tuples) that matched.


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<a name="id3200189"></a><h3>
<a name="g-relation-delete"></a>g_relation_delete ()</h3>
<a class="indexterm" name="id3200200"></a><pre class="programlisting"><a href="glib-Basic-Types.html#gint">gint</a>        g_relation_delete               (<a href="glib-Relations-and-Tuples.html#GRelation">GRelation</a> *relation,
                                             <a href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> key,
                                             <a href="glib-Basic-Types.html#gint">gint</a> field);</pre>
<p>
Deletes any records from a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a> that have the given key value in
the given field.
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<span class="term"><em class="parameter"><code>relation</code></em>&#160;:</span></td>
<td>a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>.
</td>
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<td>
<span class="term"><em class="parameter"><code>key</code></em>&#160;:</span></td>
<td>the value to compare with.
</td>
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<span class="term"><em class="parameter"><code>field</code></em>&#160;:</span></td>
<td>the field of each record to match.
</td>
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<span class="term"><span class="emphasis"><em>Returns</em></span>&#160;:</span></td>
<td>the number of records deleted.


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<a name="id3200317"></a><h3>
<a name="g-relation-destroy"></a>g_relation_destroy ()</h3>
<a class="indexterm" name="id3200328"></a><pre class="programlisting">void        g_relation_destroy              (<a href="glib-Relations-and-Tuples.html#GRelation">GRelation</a> *relation);</pre>
<p>
Destroys the <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>, freeing all memory allocated.
However, it does not free memory allocated for the
tuple data, so you should free that first if appropriate.
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<span class="term"><em class="parameter"><code>relation</code></em>&#160;:</span></td>
<td>a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>.


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<a name="id3200392"></a><h3>
<a name="g-relation-print"></a>g_relation_print ()</h3>
<a class="indexterm" name="id3200403"></a><pre class="programlisting">void        g_relation_print                (<a href="glib-Relations-and-Tuples.html#GRelation">GRelation</a> *relation);</pre>
<p>
Outputs information about all records in a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>, as well as the indexes.
It is for debugging.
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<span class="term"><em class="parameter"><code>relation</code></em>&#160;:</span></td>
<td>a <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>.


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<a name="id3200466"></a><h3>
<a name="GTuples"></a>GTuples</h3>
<a class="indexterm" name="id3200477"></a><pre class="programlisting">typedef struct {
  guint len;
} GTuples;
</pre>
<p>
The <a href="glib-Relations-and-Tuples.html#GTuples"><span class="type">GTuples</span></a> struct is used to return records (or tuples) from the
<a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a> by <a href="glib-Relations-and-Tuples.html#g-relation-select"><code class="function">g_relation_select()</code></a>.
It only contains one public member - the number of records that matched.
To access the matched records, you must use <a href="glib-Relations-and-Tuples.html#g-tuples-index"><code class="function">g_tuples_index()</code></a>.
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<span class="term"><a href="glib-Basic-Types.html#guint">guint</a>&#160;<em class="structfield"><code>len</code></em>;</span></td>
<td>the number of records that matched.

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<a name="id3200557"></a><h3>
<a name="g-tuples-destroy"></a>g_tuples_destroy ()</h3>
<a class="indexterm" name="id3200567"></a><pre class="programlisting">void        g_tuples_destroy                (<a href="glib-Relations-and-Tuples.html#GTuples">GTuples</a> *tuples);</pre>
<p>
Frees the records which were returned by <a href="glib-Relations-and-Tuples.html#g-relation-select"><code class="function">g_relation_select()</code></a>.
This should always be called after <a href="glib-Relations-and-Tuples.html#g-relation-select"><code class="function">g_relation_select()</code></a> when you are
finished with the records.
The records are not removed from the <a href="glib-Relations-and-Tuples.html#GRelation"><span class="type">GRelation</span></a>.
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<span class="term"><em class="parameter"><code>tuples</code></em>&#160;:</span></td>
<td>the tuple data to free.


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<div class="refsect2" lang="en">
<a name="id3200645"></a><h3>
<a name="g-tuples-index"></a>g_tuples_index ()</h3>
<a class="indexterm" name="id3200656"></a><pre class="programlisting"><a href="glib-Basic-Types.html#gpointer">gpointer</a>    g_tuples_index                  (<a href="glib-Relations-and-Tuples.html#GTuples">GTuples</a> *tuples,
                                             <a href="glib-Basic-Types.html#gint">gint</a> index_,
                                             <a href="glib-Basic-Types.html#gint">gint</a> field);</pre>
<p>
Gets a field from the records returned by <a href="glib-Relations-and-Tuples.html#g-relation-select"><code class="function">g_relation_select()</code></a>.
It returns the given field of the record at the given index.
The returned value should not be changed.
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<span class="term"><em class="parameter"><code>tuples</code></em>&#160;:</span></td>
<td>the tuple data, returned by <a href="glib-Relations-and-Tuples.html#g-relation-select"><code class="function">g_relation_select()</code></a>.
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<span class="term"><em class="parameter"><code>index_</code></em>&#160;:</span></td>
<td>the index of the record.
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<span class="term"><em class="parameter"><code>field</code></em>&#160;:</span></td>
<td>the field to return.
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<span class="term"><span class="emphasis"><em>Returns</em></span>&#160;:</span></td>
<td>the field of the record.


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