A Wt MVC Model to view/edit query results. More...

#include <Wt/Dbo/QueryModel>

Inheritance diagram for Wt::Dbo::QueryModel< Result >:

Public Member Functions
	QueryModel (WObject *parent=0)
	Creates a new query model. More...

void	setQuery (const Query< Result > &query, bool keepColumns=false)
	Sets the query. More...

Query< Result >	query () const
	Returns the query. More...

int	addColumn (const std::string &field, const WString &header, WFlags< ItemFlag > flags=ItemIsSelectable)
	Adds a column. More...

int	addColumn (const std::string &field, WFlags< ItemFlag > flags=ItemIsSelectable)
	Adds a column. More...

void	setColumnFlags (int column, WFlags< ItemFlag > flags)
	Sets column item flags. More...

WFlags< ItemFlag >	columnFlags (int column) const
	Returns column item flags. More...

void	addAllFieldsAsColumns ()
	Adds all the columns from the field list. More...

Result	stableResultRow (int row) const
	Returns a stable result row. More...

const Result &	resultRow (int row) const
	Returns a result row. More...

virtual Result &	resultRow (int row)
	Returns a result row. More...

int	indexOf (const Result &row) const
	Returns the index of row. More...

void	reload ()
	Rereads the data from the database. More...

void	setBatchSize (int count)
	Sets the batch size for fetching results. More...

int	batchSize () const
	Returns the batch size for fetching results. More...

const std::vector< FieldInfo > &	fields () const
	Returns the query field list. More...

const FieldInfo &	fieldInfo (int column) const
	Returns the FieldInfo structure for a column.

const std::string &	fieldName (int column) const
	Returns the field name for the a column.

virtual int	columnCount (const WModelIndex &parent=WModelIndex()) const
	Returns the number of columns. More...

virtual int	rowCount (const WModelIndex &parent=WModelIndex()) const
	Returns the number of rows. More...

virtual WFlags< ItemFlag >	flags (const WModelIndex &index) const
	Returns the flags for an item. More...

virtual boost::any	data (const WModelIndex &index, int role=DisplayRole) const
	Returns the data for an item. More...

virtual bool	setData (const WModelIndex &index, const boost::any &value, int role=EditRole)
	Sets data at the given model index. More...

virtual void	sort (int column, SortOrder order=AscendingOrder)
	Sorts the model according to a particular column. More...

virtual std::string	createOrderBy (int column, SortOrder order)
	Create specialized orderBy clause for sort. More...

virtual bool	insertRows (int row, int count, const WModelIndex &parent=WModelIndex())
	Inserts one or more rows. More...

virtual bool	removeRows (int row, int count, const WModelIndex &parent=WModelIndex())
	Removes one or more rows. More...

virtual bool	setHeaderData (int column, Orientation orientation, const boost::any &value, int role=EditRole)
	Sets header data for a column. More...

virtual boost::any	headerData (int section, Orientation orientation=Horizontal, int role=DisplayRole) const
	Returns header data. More...

virtual void *	toRawIndex (const WModelIndex &index) const
	Converts a model index to a raw pointer that remains valid while the model's layout is changed. More...

virtual WModelIndex	fromRawIndex (void *rawIndex) const
	Converts a raw pointer to a model index. More...

Public Member Functions inherited from Wt::WAbstractTableModel
	WAbstractTableModel (WObject *parent=0)
	Creates a new abstract list model.

	~WAbstractTableModel ()
	Destructor.

virtual WModelIndex	parent (const WModelIndex &index) const
	Returns the parent for a model index. More...

virtual WModelIndex	index (int row, int column, const WModelIndex &parent=WModelIndex()) const
	Returns the child index for the given row and column. More...

Public Member Functions inherited from Wt::WAbstractItemModel
	WAbstractItemModel (WObject *parent=0)
	Creates a new data model.

virtual WFlags< HeaderFlag >	headerFlags (int section, Orientation orientation=Horizontal) const
	Returns the flags for a header. More...

virtual bool	hasChildren (const WModelIndex &index) const
	Returns if there are children at an index. More...

virtual DataMap	itemData (const WModelIndex &index) const
	Returns all data at a specific index. More...

virtual WModelIndexList	match (const WModelIndex &start, int role, const boost::any &value, int hits=-1, WFlags< MatchFlag > flags=WFlags< MatchFlag >(MatchStartsWith\|MatchWrap)) const
	Returns an index list for data items that match. More...

boost::any	data (int row, int column, int role=DisplayRole, const WModelIndex &parent=WModelIndex()) const
	Returns the data item at the given column and row. More...

virtual bool	hasIndex (int row, int column, const WModelIndex &parent=WModelIndex()) const
	Returns if an index at the given position is valid (i.e. falls within the column-row bounds). More...

virtual bool	insertColumns (int column, int count, const WModelIndex &parent=WModelIndex())
	Inserts one or more columns. More...

virtual bool	removeColumns (int column, int count, const WModelIndex &parent=WModelIndex())
	Removes columns. More...

virtual bool	setItemData (const WModelIndex &index, const DataMap &values)
	Sets data at the given model index. More...

bool	setHeaderData (int section, const boost::any &value)
	Sets column header data. More...

virtual void	expandColumn (int column)
	Expands a column. More...

virtual void	collapseColumn (int column)
	Collapses a column. More...

virtual std::string	mimeType () const
	Returns a mime-type for dragging a set of indexes. More...

virtual std::vector< std::string >	acceptDropMimeTypes () const
	Returns a list of mime-types that could be accepted for a drop event. More...

virtual void	dropEvent (const WDropEvent &e, DropAction action, int row, int column, const WModelIndex &parent)
	Handles a drop event. More...

bool	insertColumn (int column, const WModelIndex &parent=WModelIndex())
	Inserts one column. More...

bool	insertRow (int row, const WModelIndex &parent=WModelIndex())
	Inserts one row. More...

bool	removeColumn (int column, const WModelIndex &parent=WModelIndex())
	Removes one column. More...

bool	removeRow (int row, const WModelIndex &parent=WModelIndex())
	Removes one row. More...

bool	setData (int row, int column, const boost::any &value, int role=EditRole, const WModelIndex &parent=WModelIndex())
	Sets data at the given row and column. More...

virtual Signal< WModelIndex, int, int > &	columnsAboutToBeInserted ()
	Signal emitted before a number of columns will be inserted. More...

virtual Signal< WModelIndex, int, int > &	columnsAboutToBeRemoved ()
	Signal emitted before a number of columns will be removed. More...

virtual Signal< WModelIndex, int, int > &	columnsInserted ()
	Signal emitted after a number of columns were inserted. More...

virtual Signal< WModelIndex, int, int > &	columnsRemoved ()
	Signal emitted after a number of columns were removed. More...

virtual Signal< WModelIndex, int, int > &	rowsAboutToBeInserted ()
	Signal emitted before a number of rows will be inserted. More...

virtual Signal< WModelIndex, int, int > &	rowsAboutToBeRemoved ()
	Signal emitted before a number of rows will be removed. More...

virtual Signal< WModelIndex, int, int > &	rowsInserted ()
	Signal emitted after a number of rows were inserted. More...

virtual Signal< WModelIndex, int, int > &	rowsRemoved ()
	Signal emitted after a number of rows were removed. More...

virtual Signal< WModelIndex, WModelIndex > &	dataChanged ()
	Signal emitted when some data was changed. More...

virtual Signal< Orientation, int, int > &	headerDataChanged ()
	Signal emitted when some header data was changed. More...

virtual Signal &	layoutAboutToBeChanged ()
	Signal emitted when the layout is about to be changed. More...

virtual Signal &	layoutChanged ()
	Signal emitted when the layout is changed. More...

virtual Signal &	modelReset ()
	Signal emitted when the model was reset. More...

Public Member Functions inherited from Wt::WObject
	WObject (WObject *parent=0)
	Create a WObject with a given parent object. More...

virtual	~WObject ()
	Destructor. More...

virtual const std::string	id () const
	Returns the (unique) identifier for this object. More...

virtual void	setObjectName (const std::string &name)
	Sets an object name. More...

virtual std::string	objectName () const
	Returns the object name. More...

void	resetLearnedSlots ()
	Resets learned stateless slot implementations. More...

template<class T >
void	resetLearnedSlot (void(T::*method)())
	Resets a learned stateless slot implementation. More...

template<class T >
WStatelessSlot *	implementStateless (void(T::*method)())
	Declares a slot to be stateless and learn client-side behaviour on first invocation. More...

template<class T >
WStatelessSlot *	implementStateless (void(T::method)(), void(T::undoMethod)())
	Declares a slot to be stateless and learn client-side behaviour in advance. More...

void	isNotStateless ()
	Marks the current function as not stateless. More...

template<class T >
WStatelessSlot *	implementJavaScript (void(T::*method)(), const std::string &jsCode)
	Provides a JavaScript implementation for a method. More...

void	addChild (WObject *child)
	Adds a child object. More...

virtual void	removeChild (WObject *child)
	Removes a child object. More...

const std::vector< WObject * > &	children () const
	Returns the children.

WObject *	parent () const
	Returns the parent object.

Protected Member Functions
virtual Result	createRow ()
	Creates a new row. More...

virtual void	addRow (Result &result)
	Adds a row to the session. More...

virtual void	deleteRow (Result &result)
	Deletes a row from the session. More...

virtual long long	resultId (const Result &result) const
	Returns a unique id for a result. More...

virtual Result	resultById (long long id) const
	Returns a result by id. More...

Protected Member Functions inherited from Wt::WAbstractItemModel
void	reset ()
	Resets the model and invalidate any data. More...

WModelIndex	createIndex (int row, int column, void *ptr) const
	Creates a model index for the given row and column. More...

WModelIndex	createIndex (int row, int column,::uint64_t id) const
	Creates a model index for the given row and column. More...

void	beginInsertColumns (const WModelIndex &parent, int first, int last)
	Method to be called before inserting columns. More...

void	beginInsertRows (const WModelIndex &parent, int first, int last)
	Method to be called before inserting rows. More...

void	beginRemoveColumns (const WModelIndex &parent, int first, int last)
	Method to be called before removing columns. More...

void	beginRemoveRows (const WModelIndex &parent, int first, int last)
	Method to be called before removing rows. More...

void	endInsertColumns ()
	Method to be called after inserting columns. More...

void	endInsertRows ()
	Method to be called after inserting rows. More...

void	endRemoveColumns ()
	Method to be called after removing columns. More...

void	endRemoveRows ()
	Method to be called after removing rows. More...

Protected Member Functions inherited from Wt::WObject
virtual WStatelessSlot *	getStateless (Method method)
	On-demand stateless slot implementation. More...

Additional Inherited Members
Public Types inherited from Wt::WAbstractItemModel
typedef std::map< int, boost::any >	DataMap
	Data map. More...

Public Types inherited from Wt::WObject
typedef void(WObject::*	Method) ()
	Typedef for a WObject method without arguments.

Static Protected Member Functions inherited from Wt::WObject
static WObject *	sender ()
	Returns the sender of the current slot call. More...

Detailed Description

template<class Result>
class Wt::Dbo::QueryModel< Result >

A Wt MVC Model to view/edit query results.

The model fetches results from the query and presents the data in a table. It supports sorting the underlying SQL query using Query::orderBy().

The default implementation of data() converts Query results to model data using query_result_traits<Result>::getValues(). You may define your own data presentation using the underlying Result by specializing data() and accessing data from resultRow().

You may selectively add fields that you want to display using addColumn(), or you can also add all columns based on the query using addAllFieldsAsColumns().

The model supports editing of the underlying data (even if the underlying query fetches results from multiple tables!). Values in columns that correspond to fields that have been mapped (and are writable) in a Database Object can be edited. The default implementation of setData() uses query_result_traits<Result>::setValue() to manipulate the database object, and thus uses the same write-behind properties as ptr<C>::modify(). To customize editing, you can specialize setData() and use resultRow() to modify the result object directly.

The model supports also inserting rows (only at the end), and removing rows, which are reflected in object additions and removals from the Session.

Editing is directly to the underlying database objects (change, insert and remove). Note that these changes will be flushed to the database whenever a transaction is committed, or before a query is run. The model will not explicitly create a transaction for the modification, but since the model uses a query for reading data, the change may be committed to the database depending on how the model is loading data. Still, this implies that usually inserting a row and setting its data happens within a single SQL "insert" statement.

To get good performance, the model keeps the following data cached:

rowCount()
a batch of data, controlled by setBatchSize()

Moreover, the model will try to fetch a batch of data even if you ask for the rowCount(), which may provide the row count as a side-effect if the query returns less results than a single batch size. If you do not want this behaviour (which might be the case if you are only interested in rowCount(), not the actual data) then you can avoid this behaviour by setting batchSize to 0.

Constructor & Destructor Documentation

template<class Result >

Wt::Dbo::QueryModel< Result >::QueryModel ( WObject * parent = 0 )

Creates a new query model.

You need to seed the model with a query using setQuery().

Member Function Documentation

template<class Result >

void Wt::Dbo::QueryModel< Result >::addAllFieldsAsColumns ( )

Adds all the columns from the field list.

All fields are added as columns. Fields that are mutable are marked as editable columns.

This is a convenient alternative to selectively adding columns using addColumn().

See also: fields()

template<class Result >

int Wt::Dbo::QueryModel< Result >::addColumn	(	const std::string &	field,
		const WString &	header,
		WFlags< ItemFlag >	flags = `ItemIsSelectable`
	)

Adds a column.

The field name may be a qualified or unqualified field name. The list of available fields can be inspected using fields().

The header is used as Wt::DisplayRole for the column header data.

For the column items, flags() will returned the given flags. For example, to indicate that a field is editable, you can set the Wt::ItemIsEditable flag.

See also: fields()

template<class Result >

int Wt::Dbo::QueryModel< Result >::addColumn	(	const std::string &	field,
		WFlags< ItemFlag >	flags = `ItemIsSelectable`
	)

Adds a column.

This is an overloaded function for convenience, which uses the field name as the header value.

See also: setHeaderData()

template<class Result >

void Wt::Dbo::QueryModel< Result >::addRow ( Result & result )

protectedvirtual

Adds a row to the session.

This method is called from within insertRows() to add (and save) a new result row to the Dbo session.

The default implementation uses query_result_traits<Result>::add().

template<class Result >

int Wt::Dbo::QueryModel< Result >::batchSize ( ) const

Returns the batch size for fetching results.

See also: setBatchSize()

template<class Result >

int Wt::Dbo::QueryModel< Result >::columnCount ( const WModelIndex & parent = WModelIndex() ) const

virtual

Returns the number of columns.

Returns the number of columns that have been added using addColumn() or addAllFieldsAsColumns().

Since the query model implements a flat table model, this returns 0 when parent is valid.

Implements Wt::WAbstractItemModel.

template<class Result >

WFlags< ItemFlag > Wt::Dbo::QueryModel< Result >::columnFlags ( int column ) const

Returns column item flags.

See also: setColumnFlags()

template<class Result >

std::string Wt::Dbo::QueryModel< Result >::createOrderBy	(	int	column,
		SortOrder	order
	)

virtual

Create specialized orderBy clause for sort.

The sort() method calls createOrderBy() to format a SQL clause for use in Query<BindStrategy>::orderBy(). The default is to return a string that will sort on a single column in the specified order.

Customize this method if you need a more complex orderBy clause, e.g. to break ties consistently.

See also: sort()

template<class Result >

Result Wt::Dbo::QueryModel< Result >::createRow ( )

protectedvirtual

Creates a new row.

This method is called from within insertRows() to create a new row.

The default implementation uses query_result_traits<Result>::create().

template<class Result >

boost::any Wt::Dbo::QueryModel< Result >::data	(	const WModelIndex &	index,
		int	role = `DisplayRole`
	)		const

virtual

Returns the data for an item.

Returns data of type Wt::DisplayRole or Wt::EditRole based on the field value corresponding to the index. If necessary, this fetches a batch of results from the underlying database.

The default implementation of data() converts Query results to model data using query_result_traits<Result>::getValues(). You may define your own data presentation using the underlying Result by specializing data() and accessing data from resultRow().

Implements Wt::WAbstractItemModel.

template<class Result >

void Wt::Dbo::QueryModel< Result >::deleteRow ( Result & result )

protectedvirtual

Deletes a row from the session.

This method is called from within removeRows() to remove (and delete) a new result row from the Dbo session.

The default implementation uses query_result_traits<Result>::remove().

template<class Result >

const std::vector< FieldInfo > & Wt::Dbo::QueryModel< Result >::fields ( ) const

Returns the query field list.

This returns the field list from the underlying query.

template<class Result >

WFlags< ItemFlag > Wt::Dbo::QueryModel< Result >::flags ( const WModelIndex & index ) const

virtual

Returns the flags for an item.

Returns the flags set for the column using setColumnFlags().

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

WModelIndex Wt::Dbo::QueryModel< Result >::fromRawIndex ( void * rawIndex ) const

virtual

Converts a raw pointer to a model index.

Use this method to create model index from temporary raw pointers. It is the reciproce method of toRawIndex().

You can return an invalid modelindex if the rawIndex no longer points to a valid item because of the layout change.

See also: toRawIndex()

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

boost::any Wt::Dbo::QueryModel< Result >::headerData	(	int	section,
		Orientation	orientation = `Horizontal`,
		int	role = `DisplayRole`
	)		const

virtual

Returns header data.

See also: setHeaderData()

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

int Wt::Dbo::QueryModel< Result >::indexOf ( const Result & row ) const

Returns the index of row.

If the row isn't contained in the model, returns -1.

template<class Result >

bool Wt::Dbo::QueryModel< Result >::insertRows	(	int	row,
		int	count,
		const WModelIndex &	parent = `WModelIndex()`
	)

virtual

Inserts one or more rows.

Row insertions are only supported at the end (row == rowCount()). For each added row, a new result is added to the underlying database.

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

Query< Result > Wt::Dbo::QueryModel< Result >::query ( ) const

Returns the query.

See also: setQuery()

template<class Result >

void Wt::Dbo::QueryModel< Result >::reload ( )

Rereads the data from the database.

This invalidates the current (cached) data and informs views that they should rerender. This emits the layoutAboutToBeChanged() signal to inform the views that data and perhaps also row count was changed.

template<class Result >

bool Wt::Dbo::QueryModel< Result >::removeRows	(	int	row,
		int	count,
		const WModelIndex &	parent = `WModelIndex()`
	)

virtual

Removes one or more rows.

For each removed row, the result is removed from the underlying database.

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

Result Wt::Dbo::QueryModel< Result >::resultById ( long long id ) const

protectedvirtual

Returns a result by id.

This should be the inverse of the resultId() function.

The default implementation uses query_result_traits<Result>::findById().

template<class Result >

long long Wt::Dbo::QueryModel< Result >::resultId ( const Result & result ) const

protectedvirtual

Returns a unique id for a result.

This should, if possible, identify the result using a unique long long id, and otherwise return -1.

The default implementation uses query_result_traits<Result>::id().

This is required for a working stableResultRow() implementation.

See also: resultById()

template<class Result >

const Result & Wt::Dbo::QueryModel< Result >::resultRow ( int row ) const

Returns a result row.

This returns the result corresponding to a particular row, and could be used to customize the model behaviour, e.g. by specializing data() for certain columns.

Returns a const reference to an entry in the result cache.

template<class Result >

Result & Wt::Dbo::QueryModel< Result >::resultRow ( int row )

virtual

Returns a result row.

This returns the result corresponding to a particular row, and could be used to customize the model behaviour, e.g. by specializing setData() for certain columns.

Returns a reference to an entry in the result cache.

See also: resultRow(int row) const

template<class Result >

int Wt::Dbo::QueryModel< Result >::rowCount ( const WModelIndex & parent = WModelIndex() ) const

virtual

Returns the number of rows.

Returns the number of rows return from the underlying query.

Since the query model implements a flat table model, this returns 0 when parent is valid.

Implements Wt::WAbstractItemModel.

template<class Result >

void Wt::Dbo::QueryModel< Result >::setBatchSize ( int count )

Sets the batch size for fetching results.

The model fetches results from the query in batch, and caches these in memory to avoid repetitive querying of the database.

The default batch size is 40.

template<class Result >

void Wt::Dbo::QueryModel< Result >::setColumnFlags	(	int	column,
		WFlags< ItemFlag >	flags
	)

Sets column item flags.

For items in column column, flags() will returned the given flags. For example, to indicate that a field is editable, you can set the Wt::ItemIsEditable flag.

template<class Result >

bool Wt::Dbo::QueryModel< Result >::setData	(	const WModelIndex &	index,
		const boost::any &	value,
		int	role = `EditRole`
	)

virtual

Sets data at the given model index.

If role = Wt::EditRole, sets the value for the field corresponding to the index. All other editing is ignored.

See also: setCachedResult()

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

bool Wt::Dbo::QueryModel< Result >::setHeaderData	(	int	column,
		Orientation	orientation,
		const boost::any &	value,
		int	role = `EditRole`
	)

virtual

Sets header data for a column.

The model will return this data in headerData(). Only column headers are supported (orientation == Wt::Horizontal).

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

void Wt::Dbo::QueryModel< Result >::setQuery	(	const Query< Result > &	query,
		bool	keepColumns = `false`
	)

Sets the query.

The query is used to query the database.

Unless keepColumns is true, this resets the column list, so you will need to (re-)add one or more columns using addColumn().

When keeping the current columns, a LayoutChange rather than a Reset is emitted by the model, allowing views to keep their column geometry as well.

template<class Result >

void Wt::Dbo::QueryModel< Result >::sort	(	int	column,
		SortOrder	order = `AscendingOrder`
	)

virtual

Sorts the model according to a particular column.

This sorts the model by changing the query using Query<BindStrategy>::orderBy().

See also: createOrderBy()

Reimplemented from Wt::WAbstractItemModel.

template<class Result >

Result Wt::Dbo::QueryModel< Result >::stableResultRow ( int row ) const

Returns a stable result row.

This return the same result row as was previously returned by resultRow(), even if there were database inserts going on.

This requires suitable implementations for resultId() and resultById() functions.

If the row wasn't fetched before (or since a reload()), then the result of resultRow() is returned instead.

template<class Result >

void * Wt::Dbo::QueryModel< Result >::toRawIndex ( const WModelIndex & index ) const

virtual

Converts a model index to a raw pointer that remains valid while the model's layout is changed.

Use this method to temporarily save model indexes while the model's layout is changed by for example a sorting operation.

The default implementation returns 0, which indicates that the index cannot be converted to a raw pointer. If you reimplement this method, you also need to reimplemnt fromRawIndex().

See also: layoutAboutToBeChanged, sort(), fromRawIndex()

Reimplemented from Wt::WAbstractItemModel.

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

template<class Result> class Wt::Dbo::QueryModel< Result >

Constructor & Destructor Documentation

Member Function Documentation

template<class Result>
class Wt::Dbo::QueryModel< Result >