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Gnome::Gda::DataHandler Class Reference
[Data Handlers]

Base class which provides data handling capabilities. More...

Inheritance diagram for Gnome::Gda::DataHandler:

Inheritance graph
[legend]
List of all members.

Public Member Functions

bool accepts_g_type (GType type) const
 Checks wether the GdaDataHandler is able to handle the gda type given as argument.
Glib::ustring get_descr () const
 Get a short description of the GdaDataHandler.
GType get_g_type_index (guint index) const
 Get the GType handled by the GdaDataHandler, at the given position (starting at zero).
unsigned int get_nb_g_types () const
 Get the number of GType types the GdaDataHandler can handle correctly.
Value get_sane_init_value (GType type) const
 Creates a new Value which holds a sane initial value to be used if no value is specifically provided.
Glib::ustring get_sql_from_value (const Value& value) const
 Creates a new string which is an SQL representation of the given value.
Glib::ustring get_str_from_value (const Value& value) const
 Creates a new string which is a "user friendly" representation of the given value (in the users's locale, specially for the dates).
Value get_value_from_sql (const Glib::ustring& sql, GType type) const
 Creates a new Value which represents the SQL value given as argument.
Value get_value_from_str (const Glib::ustring& str, GType type) const
 Creates a new Value which represents the STR value given as argument.
const GdaDataHandler* gobj () const
 Provides access to the underlying C GObject.
GdaDataHandler* gobj ()
 Provides access to the underlying C GObject.
virtual ~DataHandler ()

Static Public Member Functions

static void add_interface (GType gtype_implementer)

Related Functions

(Note that these are not member functions.)

Glib::RefPtr<Gnome::Gda::DataHandlerwrap (GdaDataHandler* object, bool take_copy=false)
 
Parameters:
object The C instance


Detailed Description

Base class which provides data handling capabilities.

Because data types vary a lot from one DBMS to another, the DataHandler interface helps with designing modules which can handle very specific pieces of data through plugins. Each object which imlements the DataHandler interface is expected to handle a subset of the possible libgda defined data types.

The DataHandler object can convert a Value to and from both SQL and 'STR'. The SQL representation of a value is the actual string which would be used in an SQL statement (for example a string's SQL representation is surrounded by quotes such as 'that a string''). The 'STR' representation is a user friendly representation of a value (and the previous example would simply be: that's a string).

Only one object which implements this interface is needed for any given data type, and it mainly contains some methods to manage values (as Value structures). The Gnome::Db::DataEntry interface is complementary to this one since it is implemented by widgets in which the user can enter or modify some data.


Constructor & Destructor Documentation

virtual Gnome::Gda::DataHandler::~DataHandler (  )  [virtual]


Member Function Documentation

bool Gnome::Gda::DataHandler::accepts_g_type ( GType  type  )  const

Checks wether the GdaDataHandler is able to handle the gda type given as argument.

Returns:
true if the gda type can be handled.

static void Gnome::Gda::DataHandler::add_interface ( GType  gtype_implementer  )  [static]

Glib::ustring Gnome::Gda::DataHandler::get_descr (  )  const

Get a short description of the GdaDataHandler.

Returns:
The description.

GType Gnome::Gda::DataHandler::get_g_type_index ( guint  index  )  const

Get the GType handled by the GdaDataHandler, at the given position (starting at zero).

Returns:
The GType.

unsigned int Gnome::Gda::DataHandler::get_nb_g_types (  )  const

Get the number of GType types the GdaDataHandler can handle correctly.

Returns:
The number.

Value Gnome::Gda::DataHandler::get_sane_init_value ( GType  type  )  const

Creates a new Value which holds a sane initial value to be used if no value is specifically provided.

For example, for a simple string, this would return a new value containing the "" string.

Parameters:
type 
Returns:
The new Value.

Glib::ustring Gnome::Gda::DataHandler::get_sql_from_value ( const Value value  )  const

Creates a new string which is an SQL representation of the given value.

If the value is 0 or is of type GDA_TYPE_0, the returned string is 0.

Parameters:
value The value to be converted to a string.
Returns:
The new string.

Glib::ustring Gnome::Gda::DataHandler::get_str_from_value ( const Value value  )  const

Creates a new string which is a "user friendly" representation of the given value (in the users's locale, specially for the dates).

If the value is 0 or is of type GDA_TYPE_0, the returned string is a copy of "" (empty string).

Parameters:
value The value to be converted to a string.
Returns:
The new string.

Value Gnome::Gda::DataHandler::get_value_from_sql ( const Glib::ustring sql,
GType  type 
) const

Creates a new Value which represents the SQL value given as argument.

This is the opposite of the function get_sql_from_value(). The type argument is used to determine the real data type requested for the returned value.

If the sql string is empty, then the returned Value is of type TYPE_NULL. If the sql string does not correspond to a valid SQL string for the requested type, then a NULL Value is returned.

Parameters:
sql 
type 
Returns:
The new Value.

Value Gnome::Gda::DataHandler::get_value_from_str ( const Glib::ustring str,
GType  type 
) const

Creates a new Value which represents the STR value given as argument.

This is the opposite of the function get_str_from_value(). The type argument is used to determine the real data type requested for the returned value.

If the str string is empty, then the returned Value is of type TYPE_NULL. If the str string does not correspond to a valid STR string for the requested type, then a NULL value is returned.

Parameters:
str 
type 
Returns:
The new Value.

const GdaDataHandler* Gnome::Gda::DataHandler::gobj (  )  const [inline]

Provides access to the underlying C GObject.

Reimplemented from Glib::Interface.

Reimplemented in Gnome::Gda::HandlerBin, Gnome::Gda::HandlerBoolean, Gnome::Gda::HandlerNumerical, Gnome::Gda::HandlerString, Gnome::Gda::HandlerTime, and Gnome::Gda::HandlerType.

GdaDataHandler* Gnome::Gda::DataHandler::gobj (  )  [inline]

Provides access to the underlying C GObject.

Reimplemented from Glib::Interface.

Reimplemented in Gnome::Gda::HandlerBin, Gnome::Gda::HandlerBoolean, Gnome::Gda::HandlerNumerical, Gnome::Gda::HandlerString, Gnome::Gda::HandlerTime, and Gnome::Gda::HandlerType.


Friends And Related Function Documentation

Glib::RefPtr<Gnome::Gda::DataHandler> wrap ( GdaDataHandler *  object,
bool  take_copy = false 
) [related]

Parameters:
object The C instance

Parameters:
take_copy False if the result should take ownership of the C instance. True if it should take a new copy or ref.
Returns:
A C++ instance that wraps this C instance.


The documentation for this class was generated from the following file:
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