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<title>Data conversions: GNOME Data Access 5 manual</title>
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<div class="chapter">
<div class="titlepage"><div><div><h2 class="title">
<a name="data_conv"></a>Data conversions</h2></div></div></div>
<div class="toc"><dl class="toc">
<dt>
<span class="refentrytitle"><a href="libgda-5.0-Default-Data-handlers.html">GdaDataHandler</a></span><span class="refpurpose"> — Interface which provides data handling (conversions) capabilities</span>
</dt>
<dt>
<span class="refentrytitle"><a href="GdaHandlerString.html">GdaHanderString</a></span><span class="refpurpose"> — Default handler for string values</span>
</dt>
<dt>
<span class="refentrytitle"><a href="GdaHandlerBoolean.html">GdaHanderBoolean</a></span><span class="refpurpose"> — Default handler for boolean values</span>
</dt>
<dt>
<span class="refentrytitle"><a href="GdaHandlerTime.html">GdaHanderTime</a></span><span class="refpurpose"> — Default handler for time values</span>
</dt>
<dt>
<span class="refentrytitle"><a href="GdaHandlerNumerical.html">GdaHanderNumerical</a></span><span class="refpurpose"> — Default handler for numeric values</span>
</dt>
<dt>
<span class="refentrytitle"><a href="GdaHandlerBin.html">GdaHanderBin</a></span><span class="refpurpose"> — Default handler for binary values</span>
</dt>
<dt>
<span class="refentrytitle"><a href="GdaHandlerType.html">GdaHanderType</a></span><span class="refpurpose"> — Default handler for GType values</span>
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<p>
A single piece of data can have several representations
depending on its usage: a string representation, an SQL representation and of course a
<a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#GValue-struct">GValue</a> representation. Conversions from one representation to
the other is DBMS dependent as each database can have its own SQL representation rules. The
<a class="link" href="libgda-5.0-Default-Data-handlers.html#GdaDataHandler">GdaDataHandler</a> object's purpose is to do all these conversions in a easy way.
Except when mentioned otherwise, conversions take into account locale settings and DBMS specifications.
</p>
<p>
To convert a data, one needs to instantiate a new data handler from one of the many classes which implement this interface, or
better to get a pointer to a <a class="link" href="libgda-5.0-Default-Data-handlers.html#GdaDataHandler">GdaDataHandler</a> object (no
need to unref() it after usage, data handler objects are stateless), and so to obtain such a pointer one can:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>Use the gda_data_handler_get_default(): the returned data handler
is a generic one and should not be used to convert data to use with any connection, but only to have
a portable way of storing and loading data in a locale independent fashion (for serialization purposes).</p></li>
<li class="listitem"><p>Ask a <a class="link" href="GdaServerProvider.html" title="GdaServerProvider">GdaServerProvider</a> object for one using the
<a class="link" href="GdaServerProvider.html#gda-server-provider-get-data-handler-g-type" title="gda_server_provider_get_data_handler_g_type ()">gda_server_provider_get_data_handler_g_type()</a>
or <a class="link" href="GdaServerProvider.html#gda-server-provider-get-data-handler-dbms" title="gda_server_provider_get_data_handler_dbms ()">gda_server_provider_get_data_handler_dbms()</a>:
the returned data handler can then safely be used to convert any data to be used with any connection
relying on the GdaServerProvider object.</p></li>
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