GdaDataModel columns

GdaDataModel columns — Management of GdaDataModel column attributes

Synopsis

                    GdaColumn;
GdaColumn *         gda_column_new                      (void);
GdaColumn *         gda_column_copy                     (GdaColumn *column);
const gchar *       gda_column_get_name                 (GdaColumn *column);
const gchar *       gda_column_get_description          (GdaColumn *column);
const gchar*        gda_column_get_dbms_type            (GdaColumn *column);
GType               gda_column_get_g_type               (GdaColumn *column);
gboolean            gda_column_get_allow_null           (GdaColumn *column);
gboolean            gda_column_get_auto_increment       (GdaColumn *column);
gint                gda_column_get_position             (GdaColumn *column);
const GValue *      gda_column_get_default_value        (GdaColumn *column);
const GValue *      gda_column_get_attribute            (GdaColumn *column,
                                                         const gchar *attribute);
void                gda_column_set_attribute            (GdaColumn *column,
                                                         const gchar *attribute,
                                                         const GValue *value,
                                                         GDestroyNotify destroy);
#define             gda_column_set_attribute_static     (holder,attribute,value)

Object Hierarchy

  GObject
   +----GdaColumn

Properties

  "id"                       gchar*                : Read / Write

Signals

  "g-type-changed"                                 : Run Last
  "name-changed"                                   : Run Last

Description

The GdaColumn object represents a GdaDataModel's column and handle all its properties.

Details

GdaColumn

typedef struct _GdaColumn GdaColumn;


gda_column_new ()

GdaColumn *         gda_column_new                      (void);

Returns :

a newly allocated GdaColumn object.

gda_column_copy ()

GdaColumn *         gda_column_copy                     (GdaColumn *column);

Creates a new GdaColumn object from an existing one.

column :

column to get a copy from.

Returns :

a newly allocated GdaColumn with a copy of the data in column.

gda_column_get_name ()

const gchar *       gda_column_get_name                 (GdaColumn *column);

column :

a GdaColumn.

Returns :

the name of column.

gda_column_get_description ()

const gchar *       gda_column_get_description          (GdaColumn *column);

column :

a GdaColumn.

Returns :

the column's description, in any

gda_column_get_dbms_type ()

const gchar*        gda_column_get_dbms_type            (GdaColumn *column);

column :

a GdaColumn.

Returns :

the database type of column.

gda_column_get_g_type ()

GType               gda_column_get_g_type               (GdaColumn *column);

column :

a GdaColumn.

Returns :

the type of column.

gda_column_get_allow_null ()

gboolean            gda_column_get_allow_null           (GdaColumn *column);

Gets the 'allow null' flag of the given column.

column :

a GdaColumn.

Returns :

whether the given column allows null values or not (TRUE or FALSE).

gda_column_get_auto_increment ()

gboolean            gda_column_get_auto_increment       (GdaColumn *column);

column :

a GdaColumn.

Returns :

whether the given column is an auto incremented one (TRUE or FALSE).

gda_column_get_position ()

gint                gda_column_get_position             (GdaColumn *column);

column :

a GdaColumn.

Returns :

the position of the column refer to in the containing data model.

gda_column_get_default_value ()

const GValue *      gda_column_get_default_value        (GdaColumn *column);

column :

a GdaColumn.

Returns :

column's default value, as a GValue object.

gda_column_get_attribute ()

const GValue *      gda_column_get_attribute            (GdaColumn *column,
                                                         const gchar *attribute);

Get the value associated to a named attribute.

Attributes can have any name, but Libgda proposes some default names, see this section.

column :

a GdaColumn

attribute :

attribute name as a string

Returns :

a read-only GValue, or NULL if not attribute named attribute has been set for column

gda_column_set_attribute ()

void                gda_column_set_attribute            (GdaColumn *column,
                                                         const gchar *attribute,
                                                         const GValue *value,
                                                         GDestroyNotify destroy);

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 this section.

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.

For example one would use it as:

gda_column_set_attribute (holder, g_strdup (my_attribute), g_free, my_value); gda_column_set_attribute (holder, GDA_ATTRIBUTE_NAME, NULL, my_value);

Note: this method does not modify in any way the contents of the data model for which column is a column (nor does it modify the table definition of the tables used by a SELECT statement is the model was created from a SELECT statement).

column :

a GdaColumn

attribute :

attribute name as a static string

value :

a GValue, or NULL

destroy :

a function to be called when attribute is not needed anymore, or NULL

gda_column_set_attribute_static()

#define gda_column_set_attribute_static(holder,attribute,value) gda_column_set_attribute((holder),(attribute),(value),NULL)

This function is similar to gda_column_set_attribute() but for static strings

holder :

a GdaHolder

attribute :

attribute's name

value :

the value to set the attribute to, or NULL

Property Details

The "id" property

  "id"                       gchar*                : Read / Write

Column's Id (warning: the column's ID is not guaranteed to be unique in a GdaDataModel).

Default value: NULL

Signal Details

The "g-type-changed" signal

void                user_function                      (GdaColumn *column,
                                                        GType     *old_type,
                                                        GType     *new_type,
                                                        gpointer   user_data)      : Run Last

Gets emitted whenever column's type has been changed

column :

the GdaColumn object

old_type :

the column's previous type

new_type :

the column's new type

user_data :

user data set when the signal handler was connected.

The "name-changed" signal

void                user_function                      (GdaColumn *column,
                                                        gchar     *old_name,
                                                        gpointer   user_data)      : Run Last

Gets emitted whenever column's name has been changed

column :

the GdaColumn object

old_name :

the column's previous name

user_data :

user data set when the signal handler was connected.