QDataBrowser Class Reference
[sql module]
The QDataBrowser class provides data manipulation and
navigation for data entry forms.
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#include <qdatabrowser.h>
Inherits QWidget.
List of all member functions.
Public Members
QDataBrowser ( QWidget * parent = 0, const char * name = 0, WFlags fl = 0 )
enum
Boundary { Unknown, None, BeforeBeginning, Beginning, End, AfterEnd }
void
setSort ( const QSqlIndex & sort )
void
setSort ( const QStringList & sort )
QStringList
sort () const
virtual void
setCursor ( QSqlCursor * cursor, bool autoDelete = FALSE )
void
setSqlCursor ( QSqlCursor * cursor, bool autoDelete = FALSE )
virtual void
setForm ( QSqlForm * form )
virtual bool
seek ( int i, bool relative = FALSE )
Public Slots
Signals
Properties
bool
autoEdit - whether the browser automatically applies edits
bool
confirmEdits - whether the browser confirms edit operations
bool
confirmInsert - whether the data browser confirms insertions
QString
filter - the data browser's filter
bool
readOnly - whether the browser is read-only
QStringList
sort - the data browser's sort
Protected Members
Detailed Description
The QDataBrowser class provides data manipulation and
navigation for data entry forms.
This class is used to manipulate and navigate data entry forms. A
high-level API is provided to navigate through data records in a
cursor, insert, update and delete records, and refresh data in the
display.
If you want a read-only form to present database data use QDataView;
if you want a table-based presentation of your data use QDataTable.
A QDataBrowser is used to associate a dataset with a form in much
the same way as a QDataTable associates a dataset with a table. Once
the data browser has been constructed it can be associated with a
dataset with setCursor() (or setSqlCursor()), and with a form with
setForm(). Boundary checking, sorting and filtering can be set with
setBoundaryChecking(), setSort() and setFilter(), respectively.
The insertCurrent() function reads the fields from the default form
into the default cursor and performs the insert. The updateCurrent()
and deleteCurrent() functions perform similarly to update and delete
the current record respectively.
The user can be asked to confirm all edits with setConfirmEdits().
For more precise control use setConfirmInsert(), setConfirmUpdate(),
setConfirmDelete() and setConfirmCancels(). Use setAutoEdit() to
control the behaviour of the form when the user edits a record and
then navigates.
The record set is navigated using first(), next(), prev(), last()
and seek(). The form's display is updated with refresh(). When
navigation takes place the firstRecordAvailable(),
lastRecordAvailable(), nextRecordAvailable() and
prevRecordAvailable() signals are emitted. When the cursor record is
changed due to navigation the cursorChanged() signal is emitted.
If you want finer control of the insert, update and delete processes
then you can use the low level functions to perform these
operations as described below.
The form is populated with data from the database with readFields().
If the user is allowed to edit, (see setReadOnly()), write the
form's data back to the cursor's edit buffer with writeFields(). You
can clear the values in the form with clearValues(). Editing is
performed as follows:
- insert When the data browser enters insertion mode it emits the
primeInsert() signal which you can connect to, for example to
pre-populate fields. Call writeFields() to write the user's edits to
the cursor's edit buffer then call insert() to insert the record
into the database. The beforeInsert() signal is emitted just before
the cursor's edit buffer is inserted into the database; connect to
this for example, to populate fields such as an auto-generated
primary key.
- update For updates the primeUpdate() signal is emitted when
the data browser enters update mode. After calling writeFields()
call update() to update the record and connect to the beforeUpdate()
signal to manipulate the user's data before the update takes place.
- delete For deletion the primeDelete() signal is emitted when
the data browser enters deletion mode. After calling writeFields()
call del() to delete the record and connect to the beforeDelete()
signal, for example to record an audit of the deleted record.
Member Type Documentation
QDataBrowser::Boundary
This enum describes where the data browser is positioned.
The currently defined values are:
- QDataBrowser::Unknown - the boundary cannot be determined (usually because
there is no default cursor, or the default cursor is not active).
- QDataBrowser::None - the browser is not positioned on a boundary, but it is
positioned on a record somewhere in the middle.
- QDataBrowser::BeforeBeginning - the browser is positioned before the
first available record.
- QDataBrowser::Beginning - the browser is positioned at the first record.
- QDataBrowser::End - the browser is positioned at the last
record.
- QDataBrowser::AfterEnd - the browser is positioned after the last
available record.
Member Function Documentation
QDataBrowser::QDataBrowser ( QWidget * parent = 0, const char * name = 0, WFlags fl = 0 )
Constructs a data browser which is a child of parent, with the
name name and widget flags set to fl.
QDataBrowser::~QDataBrowser ()
Destroys the object and frees any allocated resources.
bool QDataBrowser::autoEdit () const
Returns TRUE if the browser automatically applies edits; otherwise returns FALSE.
See the "autoEdit" property for details.
void QDataBrowser::beforeDelete ( QSqlRecord * buf ) [signal]
This signal is emitted just before the cursor's edit buffer is
deleted from the database. The buf parameter points to the edit
buffer being deleted. You might connect to this signal to capture some
auditing information about the deletion.
void QDataBrowser::beforeInsert ( QSqlRecord * buf ) [signal]
This signal is emitted just before the cursor's edit buffer is
inserted into the database. The buf parameter points to the edit
buffer being inserted. You might connect to this signal to populate a
generated primary key for example.
void QDataBrowser::beforeUpdate ( QSqlRecord * buf ) [signal]
This signal is emitted just before the cursor's edit buffer is updated
in the database. The buf parameter points to the edit buffer being
updated. You might connect to this signal to capture some auditing
information about the update.
Boundary QDataBrowser::boundary ()
Returns an enum indicating the boundary status of the browser.
This is achieved by moving the default cursor and checking the
position, however the current default form values will not be altered.
After checking for the boundary, the cursor is moved back to its
former position. See QDataBrowser::Boundary.
See also Boundary.
bool QDataBrowser::boundaryChecking () const
Returns TRUE if boundary checking is active; otherwise returns FALSE.
See the "boundaryChecking" property for details.
void QDataBrowser::clearValues () [virtual slot]
Clears all the values in the form.
All the edit buffer field values are set to their 'zero state', e.g.
0 for numeric fields and "" for string fields. Then the widgets are
updated using the property map. For example, a combobox that is
property-mapped to integers would scroll to the first item. See the
QSqlPropertyMap constructor for the default mappings of widgets
to properties.
QSql::Confirm QDataBrowser::confirmCancel ( QSql::Op m ) [virtual protected]
Protected virtual function which returns a confirmation for
cancelling an edit mode m. Derived classes can reimplement this
function and provide their own confirmation dialog. The default
implementation uses a message box which prompts the user to confirm
the edit action.
bool QDataBrowser::confirmCancels () const
Returns TRUE if the browser confirms cancel operations; otherwise returns FALSE.
See the "confirmCancels" property for details.
bool QDataBrowser::confirmDelete () const
Returns TRUE if the browser confirms deletions; otherwise returns FALSE.
See the "confirmDelete" property for details.
QSql::Confirm QDataBrowser::confirmEdit ( QSql::Op m ) [virtual protected]
Protected virtual function which returns a confirmation for an
edit of mode m. Derived classes can reimplement this function
and provide their own confirmation dialog. The default
implementation uses a message box which prompts the user to confirm
the edit action.
bool QDataBrowser::confirmEdits () const
Returns TRUE if the browser confirms edit operations; otherwise returns FALSE.
See the "confirmEdits" property for details.
bool QDataBrowser::confirmInsert () const
Returns TRUE if the data browser confirms insertions; otherwise returns FALSE.
See the "confirmInsert" property for details.
bool QDataBrowser::confirmUpdate () const
Returns TRUE if the browser confirms updates; otherwise returns FALSE.
See the "confirmUpdate" property for details.
void QDataBrowser::currentChanged ( const QSqlRecord * record ) [signal]
This signal is emitted whenever the current cursor position changes.
The record parameter points to the contents of the current cursor's
record.
bool QDataBrowser::currentEdited () [virtual protected]
Returns TRUE if the form's edit buffer differs from the current
cursor buffer, otherwise FALSE is returned.
void QDataBrowser::cursorChanged ( QSqlCursor::Mode mode ) [signal]
This signal is emitted whenever the cursor record was changed due to
navigation. The mode parameter is the edit that just took place,
e.g. Insert, Update or Delete. See QSqlCursor::Mode.
void QDataBrowser::del () [virtual slot]
Performs a delete operation on the data browser's cursor. If there
is no default cursor or no default form, nothing happens.
Otherwise, the following happens:
The current form's record is deleted from the database, providing that
the data browser is not in insert mode. If the data browser is
actively inserting a record (see insert()), the insert action is
cancelled, and the browser navigates to the last valid record that was
current. If there is an error, handleError() is called.
bool QDataBrowser::deleteCurrent () [virtual protected]
Performs a delete on the default cursor using the values from the
default form and updates the default form. If there is no default
form or no default cursor, nothing happens. If the deletion was
successful, the cursor is repositioned to the nearest record and TRUE
is returned. The nearest record is the next record if there is one
otherwise the previous record if there is one. If an error occurred
during the deletion from the database, handleError() is called and
FALSE is returned.
See also cursor, form() and handleError().
QString QDataBrowser::filter () const
Returns the data browser's filter.
See the "filter" property for details.
void QDataBrowser::first () [virtual slot]
Moves the default cursor to the first record and refreshes the
default form to display this record. If there is no default form or no
default cursor, nothing happens. If the data browser successfully
navigated to the first record, the default cursor is primed for update
and the primeUpdate() signal is emitted.
If the browser is already positioned on the first record nothing
happens.
void QDataBrowser::firstRecordAvailable ( bool available ) [signal]
This signal is emitted whenever the position of the cursor changes.
The available parameter indicates whether or not the first record
in the default cursor is available.
QSqlForm * QDataBrowser::form ()
Returns a pointer to the data browser's default form or 0 if no form
has been set.
void QDataBrowser::handleError ( const QSqlError & error ) [virtual protected]
Virtual function which handles the error error. The default
implementation warns the user with a message box.
void QDataBrowser::insert () [virtual slot]
Performs an insert operation on the data browser's cursor. If there
is no default cursor or no default form, nothing happens.
If auto-editing is on (see setAutoEdit()), the following happens:
- If the browser is already actively inserting a record,
the current form's data is inserted into the database.
- If the browser is not inserting a record, but the current record
was changed by the user, the record is updated in the database with
the current form's data (i.e. with the changes).
If there is an error handling any of the above auto-edit actions,
handleError() is called and no insert or update is performed.
If no error occurred, or auto-editing is not enabled, the data browser
begins actively inserting a record into the database by performing the
following actions:
- The default cursor is primed for insert using QSqlCursor::primeInsert().
- The primeInsert() signal is emitted.
- The form is updated with the values in the default cursor's.
edit buffer so that the user can fill in the values to be inserted.
bool QDataBrowser::insertCurrent () [virtual protected]
Reads the fields from the default form into the default cursor
and performs an insert on the default cursor. If there is no
default form or no default cursor, nothing happens. If an error
occurred during the insert into the database, handleError() is
called and FALSE is returned. If the insert was successfull, the
cursor is refreshed and relocated to the newly inserted record, the
cursorChanged() signal is emitted, and TRUE is returned.
See also cursorChanged(), sqlCursor(), form() and handleError().
bool QDataBrowser::isReadOnly () const
Returns TRUE if the browser is read-only; otherwise returns FALSE.
See the "readOnly" property for details.
void QDataBrowser::last () [virtual slot]
Moves the default cursor to the last record and refreshes the
default form to display this record. If there is no default form or no
default cursor, nothing happens. If the data browser successfully
navigated to the last record, the default cursor is primed for update
and the primeUpdate() signal is emitted.
If the browser is already positioned on the last record nothing
happens.
void QDataBrowser::lastRecordAvailable ( bool available ) [signal]
This signal is emitted whenever the position of the cursor
changes. The available parameter indicates whether or not the
last record in the default cursor is available.
void QDataBrowser::next () [virtual slot]
Moves the default cursor to the next record and refreshes the
default form to display this record. If there is no default form or no
default cursor, nothing happens. If the data browser successfully
navigated to the next record, the default cursor is primed for update
and the primeUpdate() signal is emitted.
If the browser is positioned on the last record nothing happens.
void QDataBrowser::nextRecordAvailable ( bool available ) [signal]
This signal is emitted whenever the position of the cursor
changes. The available parameter indicates whether or not the
next record in the default cursor is available.
void QDataBrowser::prev () [virtual slot]
Moves the default cursor to the previous record and refreshes the
default form to display this record. If there is no default form or no
default cursor, nothing happens. If the data browser successfully
navigated to the previous record, the default cursor is primed for
update and the primeUpdate() signal is emitted.
If the browser is positioned on the first record nothing happens.
void QDataBrowser::prevRecordAvailable ( bool available ) [signal]
This signal is emitted whenever the position of the cursor
changes. The available parameter indicates whether or not the
previous record in the default cursor is available.
void QDataBrowser::primeDelete ( QSqlRecord * buf ) [signal]
This signal is emitted when the data browser enters deletion mode.
The buf parameter points to the record buffer being deleted. (Note
that QSqlCursor::primeDelete() is not called on the default cursor,
as this would corrupt values in the form.) Connect to this signal in
order to, for example, save a copy of the deleted record for auditing
purposes.
See also del().
void QDataBrowser::primeInsert ( QSqlRecord * buf ) [signal]
This signal is emitted when the data browser enters insertion mode.
The buf parameter points to the record buffer that is to be
inserted. Connect to this signal to, for example, prime the record
buffer with default data values, auto-numbered fields etc. (Note that
QSqlCursor::primeInsert() is not called on the default cursor, as
this would corrupt values in the form.)
See also insert().
void QDataBrowser::primeUpdate ( QSqlRecord * buf ) [signal]
This signal is emitted when the data browser enters update mode. Note
that during naviagtion (first(), last(), next(), prev()), each record
that is shown in the default form is primed for update. The buf
parameter points to the record buffer being updated. (Note that
QSqlCursor::primeUpdate() is not called on the default cursor, as
this would corrupt values in the form.) Connect to this signal in
order to, for example, keep track of which records have been updated,
perhaps for auditing purposes.
See also update().
void QDataBrowser::readFields () [virtual slot]
Reads the fields from the default cursor's edit buffer and displays
them in the form. If there is no default cursor or no default form,
nothing happens.
void QDataBrowser::refresh () [virtual slot]
Refreshes the data browser's data using the default cursor. The
browser's current filter and sort are applied if they have been set.
See also filter and sort.
bool QDataBrowser::seek ( int i, bool relative = FALSE ) [virtual]
Moves the default cursor to the record specified by the index i and refreshes the default form to display this record. If there is
no default form or no default cursor, nothing happens. If relative
is TRUE (the default is FALSE), the cursor is moved relative to its
current position. If the data browser successfully navigated to the
desired record, the default cursor is primed for update and the
primeUpdate() signal is emitted.
If the browser is already positioned on the desired record nothing
happens.
void QDataBrowser::setAutoEdit ( bool autoEdit ) [virtual]
Sets whether the browser automatically applies edits to autoEdit.
See the "autoEdit" property for details.
void QDataBrowser::setBoundaryChecking ( bool active )
Sets whether boundary checking is active to active.
See the "boundaryChecking" property for details.
void QDataBrowser::setConfirmCancels ( bool confirm ) [virtual]
Sets whether the browser confirms cancel operations to confirm.
See the "confirmCancels" property for details.
void QDataBrowser::setConfirmDelete ( bool confirm ) [virtual]
Sets whether the browser confirms deletions to confirm.
See the "confirmDelete" property for details.
void QDataBrowser::setConfirmEdits ( bool confirm ) [virtual]
Sets whether the browser confirms edit operations to confirm.
See the "confirmEdits" property for details.
void QDataBrowser::setConfirmInsert ( bool confirm ) [virtual]
Sets whether the data browser confirms insertions to confirm.
See the "confirmInsert" property for details.
void QDataBrowser::setConfirmUpdate ( bool confirm ) [virtual]
Sets whether the browser confirms updates to confirm.
See the "confirmUpdate" property for details.
void QDataBrowser::setCursor ( QSqlCursor * cursor, bool autoDelete = FALSE ) [virtual]
Sets the default cursor used by the data browser to cursor. If autoDelete is TRUE (the default is FALSE), the data browser takes
ownership of the cursor pointer, which will be deleted when the
browser is destroyed, or when setCursor() is called again. To
activate the cursor use refresh(). The cursor's edit buffer is
used in the default form to browse and edit records.
See also cursor, form() and setForm().
void QDataBrowser::setFilter ( const QString & filter )
Sets the data browser's filter to filter.
See the "filter" property for details.
void QDataBrowser::setForm ( QSqlForm * form ) [virtual]
Sets the browser's default form to form. The cursor and all
navigation and data manipulation functions that the browser provides
become available to the form.
void QDataBrowser::setReadOnly ( bool active ) [virtual]
Sets whether the browser is read-only to active.
See the "readOnly" property for details.
void QDataBrowser::setSort ( const QStringList & sort )
Sets the data browser's sort to sort.
See the "sort" property for details.
void QDataBrowser::setSort ( const QSqlIndex & sort )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the data browser's sort to the QSqlIndex sort. To apply the
new sort, use refresh().
void QDataBrowser::setSqlCursor ( QSqlCursor * cursor, bool autoDelete = FALSE )
Sets the default cursor used by the data browser to cursor. If autoDelete is TRUE, the browser will take ownership of the cursor and delete it when appropriate. This function is a wrapper
for setCursor() and is provided purely for consistency with
sqlCursor(). We recommend using setCursor() directly.
See also sqlCursor().
QStringList QDataBrowser::sort () const
Returns the data browser's sort.
See the "sort" property for details.
QSqlCursor * QDataBrowser::sqlCursor () const
Returns a pointer to the default cursor used for navigation, or 0
if there is no default cursor.
See also setCursor().
void QDataBrowser::update () [virtual slot]
Performs an update operation on the data browser's cursor.
If there is no default cursor or no default form, nothing happens.
Otherwise, the following happens:
If the data browser is actively inserting a record (see insert()),
that record is inserted into the database using insertCurrent().
Otherwise, the database is updated with the current form's data using
updateCurrent(). If there is an error handling either action,
handleError() is called.
void QDataBrowser::updateBoundary () [slot]
If boundaryChecking() is TRUE, checks the boundary of the current
default cursor and emits signals which indicate the position of the
cursor.
bool QDataBrowser::updateCurrent () [virtual protected]
Reads the fields from the default form into the default cursor
and performs an update on the default cursor. If there is no default
form or no default cursor, nothing happens. If an error occurred during
the update on the database, handleError() is called and FALSE is
returned. If the update was successfull, the cursor is refreshed and
relocated to the updated record, the cursorChanged() signal is
emitted, and TRUE is returned.
See also cursor, form() and handleError().
void QDataBrowser::writeFields () [virtual slot]
Writes the form's data to the default cursor's edit buffer. If
there is no default cursor or no default form, nothing happens.
Property Documentation
bool autoEdit
This property holds whether the browser automatically applies edits.
The default value for this property is TRUE. When the user begins an
insertion or an update on a form there are two possible outcomes when
they navigate to another record:
- the insert or update is is performed -- this occurs if autoEdit is TRUE
- the insert or update is discarded -- this occurs if autoEdit is FALSE
Set this property's value with setAutoEdit() and get this property's value with autoEdit().
bool boundaryChecking
This property holds whether boundary checking is active.
When boundary checking is active, signals are emitted indicating
the current position of the default cursor.
See also boundary().
Set this property's value with setBoundaryChecking() and get this property's value with boundaryChecking().
bool confirmCancels
This property holds whether the browser confirms cancel operations.
If this property is TRUE, all cancels must be
confirmed by the user through a message box (this behavior can be
changed by overriding the confirmCancel() function), otherwise all
cancels occur immediately.
See also confirmEdits and confirmCancel().
Set this property's value with setConfirmCancels() and get this property's value with confirmCancels().
bool confirmDelete
This property holds whether the browser confirms deletions.
If this property is TRUE, the browser confirms deletions,
otherwise deletions happen immediately.
See also confirmCancels, confirmEdits, confirmUpdate, confirmInsert and confirmEdit().
Set this property's value with setConfirmDelete() and get this property's value with confirmDelete().
bool confirmEdits
This property holds whether the browser confirms edit operations.
If this property is TRUE, the browser confirms all edit operations
(insertions, updates and deletions), otherwise all edit operations
happen immediately. Confirmation is achieved by presenting the user
with a message box -- this behavior can be changed by reimplementing
the confirmEdit() function,
See also confirmEdit(), confirmCancels, confirmInsert, confirmUpdate and confirmDelete.
Set this property's value with setConfirmEdits() and get this property's value with confirmEdits().
bool confirmInsert
This property holds whether the data browser confirms insertions.
If this property is TRUE, the browser confirms insertions,
otherwise insertions happen immediately.
See also confirmCancels, confirmEdits, confirmUpdate, confirmDelete and confirmEdit().
Set this property's value with setConfirmInsert() and get this property's value with confirmInsert().
bool confirmUpdate
This property holds whether the browser confirms updates.
If this property is TRUE, the browser confirms updates,
otherwise updates happen immediately.
See also confirmCancels, confirmEdits, confirmInsert, confirmDelete and confirmEdit().
Set this property's value with setConfirmUpdate() and get this property's value with confirmUpdate().
This property holds the data browser's filter.
The filter applies to the data shown in the browser. Call refresh() to
apply the new filter. A filter is a string containing a SQL WHERE
clause without the WHERE keyword, e.g. "id>1000", "name LIKE 'A%'".
See also sort.
Set this property's value with setFilter() and get this property's value with filter().
bool readOnly
This property holds whether the browser is read-only.
If the data browser is read-only, no database edits will be allowed.
Set this property's value with setReadOnly() and get this property's value with isReadOnly().
This property holds the data browser's sort.
The data browser's sort affects the order in which records are
viewed in the browser. Call refresh() to apply the new sort.
When retrieving the sort property, a string list is returned in the
form 'fieldname order', e.g. 'id ASC', 'surname DESC'.
See also filter and refresh().
Set this property's value with setSort() and get this property's value with sort().
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