Set the value associated to a named attribute. The attribute string is 'stolen' by this method, and
the memory it uses will be freed using the destroy function when no longer needed (if destroy is null,
then the string will not be freed at all).
Attributes can have any name, but Libgda proposes some default names,
see <link linkend="libgda-5.0-Attributes-manager.synopsis">this section</link>.
If there is already an attribute named attribute set, then its value is replaced with the new value (value is
copied), except if value is null, in which case the attribute is removed.
Set the value associated to a named attribute. The attribute string is 'stolen' by this method, and the memory it uses will be freed using the destroy function when no longer needed (if destroy is null, then the string will not be freed at all).
Attributes can have any name, but Libgda proposes some default names, see <link linkend="libgda-5.0-Attributes-manager.synopsis">this section</link>.
For example one would use it as:
<code>gda_holder_set_attribute (holder, g_strdup (my_attribute), my_value, g_free);</code> <code>gda_holder_set_attribute (holder, GDA_ATTRIBUTE_NAME, my_value, NULL);</code>
If there is already an attribute named attribute set, then its value is replaced with the new value (value is copied), except if value is null, in which case the attribute is removed.