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GNOME Data Access 4.0 manual | ![]() |
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GdaDataModelIter; const GValue* gda_data_model_iter_get_value_at (GdaDataModelIter *iter, gint col); const GValue* gda_data_model_iter_get_value_for_field (GdaDataModelIter *iter, const gchar *field_name); gboolean gda_data_model_iter_is_valid (GdaDataModelIter *iter); gboolean gda_data_model_iter_set_at_row (GdaDataModelIter *iter, gint row); gboolean gda_data_model_iter_move_next (GdaDataModelIter *iter); gboolean gda_data_model_iter_move_prev (GdaDataModelIter *iter); gint gda_data_model_iter_get_row (GdaDataModelIter *iter); GdaHolder* gda_data_model_iter_get_holder_for_field (GdaDataModelIter *iter, gint col); void gda_data_model_iter_invalidate_contents (GdaDataModelIter *iter);
"current-row" gint : Read / Write "data-model" GdaDataModel : Read / Write / Construct Only "forced-model" GdaDataModel : Read / Write "update-model" gboolean : Read / Write
A GdaDataModelIter object is used to iterate through the rows of a GdaDataModel. If the data model is accessible
in a random access way then any number of GdaDataModelIter objects can be created on the same data model, and
if the data model only supports a cursor based access then only one GdaDataModelIter can be created. In any case
creating a GdaDataModelIter should be done using the gda_data_model_create_iter()
method. Note that if
the data model only supports a cursor based access, then calling this method several times will always return
the same GdaDataModelIter, but with its reference count increased by 1 (so you should call g_object_unref()
when
finished with it).
When a GdaDataModelIter is valid (that is when it points to an existing row in the data model it iterates through),
the individual values (corresponding to each column of the data model, at the pointer row) can be accessed
using the gda_data_model_iter_get_value_at()
or gda_data_model_iter_get_value_for_field()
methods
(or in the same way GdaSet's values are accessed as GdaDataModelIter inherits the GdaSet).
Right after being created, a GdaDataModelIter is invalid (does not point to any row of its data model). To read the
first row of the data model, use the gda_data_model_iter_move_next()
method. Calling this method several times will
move the iterator forward, up to when the data model has no more rows and the GdaDataModelIter will be declared invalid
(and gda_data_model_iter_move_next()
has returned FALSE). Note that at this point, the number of rows in the data
model will be known.
If the data model supports it, a GdaDataModelIter can be moved backwards using the gda_data_model_iter_move_prev()
method. However if the iterator is invalid, moving backwards will not be possible (on the contrary to
gda_data_model_iter_move_next()
which moves to the first row).
The gda_data_model_iter_set_at_row()
method, if the iterator can be moved both forward and backwards, can move the
iterator to a specific row (sometimes faster than moving it forward or backwards a number of times).
const GValue* gda_data_model_iter_get_value_at (GdaDataModelIter *iter, gint col);
Get the value stored at the column col
in iter
iter : |
a GdaDataModelIter object |
col : |
the requested column |
Returns : | the GValue, or NULL
|
const GValue* gda_data_model_iter_get_value_for_field (GdaDataModelIter *iter, const gchar *field_name);
Get the value stored at the column field_name
in iter
iter : |
a GdaDataModelIter object |
field_name : |
the requested column name |
Returns : | the GValue, or NULL
|
gboolean gda_data_model_iter_is_valid (GdaDataModelIter *iter);
Tells if iter
is a valid iterator (if it actually corresponds to a valid row in the model)
iter : |
a GdaDataModelIter object |
Returns : | TRUE if iter is valid
|
gboolean gda_data_model_iter_set_at_row (GdaDataModelIter *iter, gint row);
Synchronizes the values of the parameters in iter
with the values at the row
row
If row
< 0 then iter
is not bound to any row of the data model it iters through.
iter : |
a GdaDataModelIter object |
row : |
the row to set iter to
|
Returns : | TRUE if no error occurred |
gboolean gda_data_model_iter_move_next (GdaDataModelIter *iter);
Moves iter
one row further than where it already is (synchronizes the values of the parameters in iter
with the values at the new row).
iter : |
a GdaDataModelIter object |
Returns : | TRUE if no error occurred |
gboolean gda_data_model_iter_move_prev (GdaDataModelIter *iter);
Moves iter
one row before where it already is (synchronizes the values of the parameters in iter
with the values at the new row).
iter : |
a GdaDataModelIter object |
Returns : | TRUE if no error occurred |
gint gda_data_model_iter_get_row (GdaDataModelIter *iter);
Get the row which iter
represents in the data model
iter : |
a GdaDataModelIter object |
Returns : | the row number, or -1 if not available |
GdaHolder* gda_data_model_iter_get_holder_for_field (GdaDataModelIter *iter, gint col);
Fetch a pointer to the GdaHolder object which is synchronized with data at
column col
iter : |
a GdaDataModelIter object |
col : |
the requested column |
Returns : | the GdaHolder, or NULL if an error occurred
|
void gda_data_model_iter_invalidate_contents (GdaDataModelIter *iter);
Declare all the parameters in iter
invalid, without modifying the
GdaDataModel iter
is for or changing the row it represents. This method
is for internal usage.
iter : |
a GdaDataModelIter object |
current-row
" property"current-row" gint : Read / Write
Allowed values: >= -1
Default value: -1
void user_function (GdaDataModelIter *gdadatamodeliter, gpointer user_data) : Run First
gdadatamodeliter : |
the object which received the signal. |
user_data : |
user data set when the signal handler was connected. |
void user_function (GdaDataModelIter *gdadatamodeliter, gint arg1, gpointer user_data) : Run First
gdadatamodeliter : |
the object which received the signal. |
arg1 : |
|
user_data : |
user data set when the signal handler was connected. |
gboolean user_function (GdaDataModelIter *gdadatamodeliter, gint arg1, gpointer user_data) : Run Last
gdadatamodeliter : |
the object which received the signal. |
arg1 : |
|
user_data : |
user data set when the signal handler was connected. |
Returns : |