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q3sqlform.cpp

/****************************************************************************
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of the Qt3Support module of the Qt Toolkit.
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** and appearing in the file LICENSE.GPL included in the packaging of
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#include "q3sqlform.h"

#ifndef QT_NO_SQL_FORM

#include "qsqlfield.h"
#include "q3sqlpropertymap.h"
#include "qsqlrecord.h"
#include "qstringlist.h"
#include "qwidget.h"
#include "qhash.h"

class Q3SqlFormPrivate
{
public:
    Q3SqlFormPrivate() : propertyMap(0), buf(0), dirty(false) {}
    ~Q3SqlFormPrivate() { if (propertyMap) delete propertyMap; }
    QStringList fld;
    QHash <QString, QWidget*> wgt;
    QMap <QWidget*, QSqlField *> map;
    Q3SqlPropertyMap * propertyMap;
    QSqlRecord* buf;
    bool dirty;
};

/*!
    \class Q3SqlForm
    \brief The Q3SqlForm class creates and manages data entry forms
    tied to SQL databases.

    \compat

    Typical use of a Q3SqlForm consists of the following steps:
    \list
    \i Create the widgets you want to appear in the form.
    \i Create a cursor and navigate to the record to be edited.
    \i Create the Q3SqlForm.
    \i Set the form's record buffer to the cursor's update buffer.
    \i Insert each widget and the field it is to edit into the form.
    \i Use readFields() to update the editor widgets with values from
    the database's fields.
    \i Display the form and let the user edit values etc.
    \i Use writeFields() to update the database's field values with
    the values in the editor widgets.
    \endlist

    Note that a Q3SqlForm does not access the database directly, but
    most often via QSqlFields which are part of a Q3SqlCursor. A
    Q3SqlCursor::insert(), Q3SqlCursor::update() or Q3SqlCursor::del()
    call is needed to actually write values to the database.

    Some sample code to initialize a form successfully:

    \code
    QLineEdit  myEditor(this);
    Q3SqlForm   myForm(this);
    Q3SqlCursor myCursor("mytable");

    // Execute a query to make the cursor valid
    myCursor.select();
    // Move the cursor to a valid record (the first record)
    myCursor.next();
    // Set the form's record pointer to the cursor's edit buffer (which
    // contains the current record's values)
    myForm.setRecord(myCursor.primeUpdate());

    // Insert a field into the form that uses myEditor to edit the
    // field 'somefield' in 'mytable'
    myForm.insert(&myEditor, "somefield");

    // Update myEditor with the value from the mapped database field
    myForm.readFields();
    ...
    // Let the user edit the form
    ...
    // Update the database
    myForm.writeFields();  // Update the cursor's edit buffer from the form
    myCursor.update();        // Update the database from the cursor's buffer
    \endcode

    If you want to use custom editors for displaying and editing data
    fields, you must install a custom Q3SqlPropertyMap. The form
    uses this object to get or set the value of a widget.

    \sa installPropertyMap(), Q3SqlPropertyMap
*/


/*!
    Constructs a Q3SqlForm with parent \a parent.
*/
00114 Q3SqlForm::Q3SqlForm(QObject * parent)
    : QObject(parent)
{
    d = new Q3SqlFormPrivate();
}

/*!
    Destroys the object and frees any allocated resources.
*/
00123 Q3SqlForm::~Q3SqlForm()
{
    delete d;
}

/*!
    Installs a custom Q3SqlPropertyMap. This is useful if you plan to
    create your own custom editor widgets.

    Q3SqlForm takes ownership of \a pmap, so \a pmap is deleted when
    Q3SqlForm goes out of scope.

    \sa Q3DataTable::installEditorFactory()
*/
00137 void Q3SqlForm::installPropertyMap(Q3SqlPropertyMap * pmap)
{
    if(d->propertyMap)
        delete d->propertyMap;
    d->propertyMap = pmap;
}

/*!
    Sets \a buf as the record buffer for the form. To force the
    display of the data from \a buf, use readFields().

    \sa readFields() writeFields()
*/

00151 void Q3SqlForm::setRecord(QSqlRecord* buf)
{
    d->dirty = true;
    d->buf = buf;
}

/*!
    Inserts a \a widget, and the name of the \a field it is to be
    mapped to, into the form. To actually associate inserted widgets
    with an edit buffer, use setRecord().

    \sa setRecord()
*/

00165 void Q3SqlForm::insert(QWidget * widget, const QString& field)
{
    d->dirty = true;
    d->wgt.insert(field, widget);
    d->fld += field;
}

/*!
    \overload

    Removes \a field from the form.
*/

00178 void Q3SqlForm::remove(const QString& field)
{
    d->dirty = true;
    int i = d->fld.indexOf(field);
    if (i >= 0)
        d->fld.removeAt(i);
    d->wgt.remove(field);
}

/*!
    \overload

    Inserts a \a widget, and the \a field it is to be mapped to, into
    the form.
*/

00194 void Q3SqlForm::insert(QWidget * widget, QSqlField * field)
{
    d->map[widget] = field;
}

/*!
    Removes a \a widget, and hence the field it's mapped to, from the
    form.
*/

00204 void Q3SqlForm::remove(QWidget * widget)
{
    d->map.remove(widget);
}

/*!
    Clears the values in all the widgets, and the fields they are
    mapped to, in the form, and sets them to NULL.
*/
00213 void Q3SqlForm::clearValues()
{
    QMap< QWidget *, QSqlField * >::Iterator it;
    for(it = d->map.begin(); it != d->map.end(); ++it){
        QSqlField* f = (*it);
        if (f)
            f->clear();
    }
    readFields();
}

/*!
    Removes every widget, and the fields they're mapped to, from the form.
*/
00227 void Q3SqlForm::clear()
{
    d->dirty = true;
    d->fld.clear();
    clearMap();
}

/*!
    Returns the number of widgets in the form.
*/
00237 int Q3SqlForm::count() const
{
    return d->map.size();
}

/*!
    Returns the \a{i}-th widget in the form. Useful for traversing
    the widgets in the form.
*/
00246 QWidget * Q3SqlForm::widget(int i) const
{
    QMap< QWidget *, QSqlField * >::ConstIterator it;
    int cnt = 0;

    if(i > d->map.size())
        return 0;
    for(it = d->map.constBegin(); it != d->map.constEnd(); ++it){
        if(cnt++ == i)
            return it.key();
    }
    return 0;
}

/*!
    Returns the widget that field \a field is mapped to.
*/
00263 QWidget * Q3SqlForm::fieldToWidget(QSqlField * field) const
{
    QMap< QWidget *, QSqlField * >::ConstIterator it;
    for(it = d->map.constBegin(); it != d->map.constEnd(); ++it){
        if(*it == field)
            return it.key();
    }
    return 0;
}

/*!
    Returns the SQL field that widget \a widget is mapped to.
*/
00276 QSqlField * Q3SqlForm::widgetToField(QWidget * widget) const
{
    return d->map.value(widget, 0);
}

/*!
    Updates the widgets in the form with current values from the SQL
    fields they are mapped to.
*/
00285 void Q3SqlForm::readFields()
{
    sync();
    QSqlField * f;
    QMap< QWidget *, QSqlField * >::Iterator it;
    Q3SqlPropertyMap * pmap = (d->propertyMap == 0) ?
                             Q3SqlPropertyMap::defaultMap() : d->propertyMap;
    for(it = d->map.begin() ; it != d->map.end(); ++it){
        f = widgetToField(it.key());
        if(!f)
            continue;
        pmap->setProperty(it.key(), f->value());
    }
}

/*!
    Updates the SQL fields with values from the widgets they are
    mapped to. To actually update the database with the contents of
    the record buffer, use Q3SqlCursor::insert(), Q3SqlCursor::update()
    or Q3SqlCursor::del() as appropriate.
*/
00306 void Q3SqlForm::writeFields()
{
    sync();
    QSqlField * f;
    QMap< QWidget *, QSqlField * >::Iterator it;
    Q3SqlPropertyMap * pmap = (d->propertyMap == 0) ?
                             Q3SqlPropertyMap::defaultMap() : d->propertyMap;

    for(it = d->map.begin() ; it != d->map.end(); ++it){
        f = widgetToField(it.key());
        if(!f)
            continue;
        f->setValue(pmap->property(it.key()));
    }
}

/*!
    Updates the widget \a widget with the value from the SQL field it
    is mapped to. Nothing happens if no SQL field is mapped to the \a
    widget.
*/
00327 void Q3SqlForm::readField(QWidget * widget)
{
    sync();
    QSqlField * field = 0;
    Q3SqlPropertyMap * pmap = (d->propertyMap == 0) ?
                             Q3SqlPropertyMap::defaultMap() : d->propertyMap;
    field = widgetToField(widget);
    if(field)
        pmap->setProperty(widget, field->value());
}

/*!
    Updates the SQL field with the value from the \a widget it is
    mapped to. Nothing happens if no SQL field is mapped to the \a
    widget.
*/
00343 void Q3SqlForm::writeField(QWidget * widget)
{
    sync();
    QSqlField * field = 0;
    Q3SqlPropertyMap * pmap = (d->propertyMap == 0) ?
                             Q3SqlPropertyMap::defaultMap() : d->propertyMap;
    field = widgetToField(widget);
    if(field)
        field->setValue(pmap->property(widget));
}

/*! \internal
*/

00357 void Q3SqlForm::sync()
{
    if (d->dirty) {
        clearMap();
        if (d->buf) {
            for (int i = 0; i < d->fld.count(); ++i) {
                const QSqlField *field = d->buf->fieldPtr(d->fld.at(i));
                insert(d->wgt.value(d->fld.at(i)), const_cast<QSqlField *>(field));
            }
        }
    }
    d->dirty = false;
}

/*! \internal

  Clears the internal map of widget/field associations
*/

00376 void Q3SqlForm::clearMap()
{
    d->map.clear();
}

#endif // QT_NO_SQL

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