q3databrowser.cpp

奇趣公司比较新的qt/emd版本

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#include "q3databrowser.h"

#ifndef QT_NO_SQL_VIEW_WIDGETS

#include "q3sqlform.h"
#include "private/q3sqlmanager_p.h"
#include "qsqlresult.h"

class Q3DataBrowserPrivate
{
public:
    Q3DataBrowserPrivate() : boundaryCheck(true), readOnly(false) {}
    Q3SqlCursorManager cur;
    Q3SqlFormManager frm;
    Q3DataManager dat;
    bool boundaryCheck;
    bool readOnly;
};

/*!
    \class Q3DataBrowser qdatabrowser.h
    \brief The Q3DataBrowser class provides data manipulation and
    navigation for data entry forms.

    \compat

    A high-level API is provided for navigating through data records
    in a cursor, for inserting, updating and deleting records, and for
    refreshing data in the display.

    If you want a read-only form to present database data use
    Q3DataView; if you want a table-based presentation of your data use
    Q3DataTable.

    A Q3DataBrowser is used to associate a dataset with a form in much
    the same way as a Q3DataTable associates a dataset with a table.
    Once the data browser has been constructed it can be associated
    with a dataset with 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 behavior 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 lower 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:
    \list
    \i \e 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.
    \i \e 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.
    \i \e 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.
    \endlist

*/

/*!
    \enum Q3DataBrowser::Boundary

    This enum describes where the data browser is positioned.

    \value Unknown  the boundary cannot be determined (usually because
    there is no default cursor, or the default cursor is not active).

    \value None  the browser is not positioned on a boundary, but it is
    positioned on a record somewhere in the middle.

    \value BeforeBeginning  the browser is positioned before the
    first available record.

    \value Beginning  the browser is positioned at the first record.

    \value End  the browser is positioned at the last
    record.

    \value AfterEnd  the browser is positioned after the last
    available record.
*/

/*!
    Constructs a data browser which is a child of \a parent, with the
    name \a name and widget flags set to \a fl.
*/

Q3DataBrowser::Q3DataBrowser(QWidget *parent, const char *name, Qt::WindowFlags fl)
    : QWidget(parent, name, fl)
{
    d = new Q3DataBrowserPrivate();
    d->dat.setMode(QSql::Update);
}

/*!
    Destroys the object and frees any allocated resources.
*/

Q3DataBrowser::~Q3DataBrowser()
{
    delete d;
}


/*!
    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 \l Q3DataBrowser::Boundary.

    \sa Boundary
*/

Q3DataBrowser::Boundary Q3DataBrowser::boundary()
{
    Q3SqlCursor* cur = d->cur.cursor();
    if (!cur || !cur->isActive())
        return Unknown;
    if (!cur->isValid()) {
        if (cur->at() == QSql::BeforeFirst)
            return BeforeBeginning;
        if (cur->at() == QSql::AfterLast)
            return AfterEnd;
        return Unknown;
    }
    if (cur->at() == 0)
        return Beginning;
    int currentAt = cur->at();

    Boundary b = None;
    if (!cur->previous())
        b = Beginning;
    else
        cur->seek(currentAt);
    if (b == None && !cur->next())
        b = End;
    cur->seek(currentAt);
    return b;
}


/*!
    \property Q3DataBrowser::boundaryChecking
    \brief whether boundary checking is active

    When boundary checking is active (the default), signals are
    emitted indicating the current position of the default cursor.

    \sa boundary()
*/

void Q3DataBrowser::setBoundaryChecking(bool active)
{
    d->boundaryCheck = active;
}

bool Q3DataBrowser::boundaryChecking() const
{
    return d->boundaryCheck;
}

/*!
    \property Q3DataBrowser::sort
    \brief 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'.

    There is no default sort.

    Note that if you want to iterate over the list, you should iterate
    over a copy, e.g.
    \code
    QStringList list = myDataBrowser.sort();
    QStringList::Iterator it = list.begin();
    while(it != list.end()) {
        myProcessing(*it);
        ++it;
    }
    \endcode
*/

void Q3DataBrowser::setSort(const QStringList& sort)
{
    d->cur.setSort(sort);
}

/*!
    \overload

    Sets the data browser's sort to the QSqlIndex \a sort. To apply
    the new sort, use refresh().

*/
void Q3DataBrowser::setSort(const QSqlIndex& sort)
{
    d->cur.setSort(sort);
}

QStringList Q3DataBrowser::sort() const
{
    return d->cur.sort();
}


/*!
    \property Q3DataBrowser::filter
    \brief 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%'", etc.

    There is no default filter.

    \sa sort()
*/

void Q3DataBrowser::setFilter(const QString& filter)
{
    d->cur.setFilter(filter);
}


QString Q3DataBrowser::filter() const
{
    return d->cur.filter();
}


/*!
    Sets the default cursor used by the data browser to \a cursor. If
    \a autoDelete is true (the default is false), the data browser
    takes ownership of the \a cursor pointer, which will be deleted
    when the browser is destroyed, or when setSqlCursor() is called
    again. To activate the \a cursor use refresh(). The cursor's edit
    buffer is used in the default form to browse and edit records.

    \sa sqlCursor() form() setForm()
*/

void Q3DataBrowser::setSqlCursor(Q3SqlCursor* cursor, bool autoDelete)
{
    if (!cursor)
        return;
    d->cur.setCursor(cursor, autoDelete);
    d->frm.setRecord(cursor->editBuffer());
    if (cursor->isReadOnly())
        setReadOnly(true);
}


/*!
    Returns the default cursor used for navigation, or 0 if there is
    no default cursor.

    \sa setSqlCursor()
*/

Q3SqlCursor* Q3DataBrowser::sqlCursor() const
{
    return d->cur.cursor();
}


/*!
    Sets the browser's default form to \a form. The cursor and all
    navigation and data manipulation functions that the browser
    provides become available to the \a form.
*/

void Q3DataBrowser::setForm(Q3SqlForm* form)
{
    d->frm.setForm(form);
}


/*!
    Returns the data browser's default form or 0 if no form has been
    set.
*/

Q3SqlForm* Q3DataBrowser::form()
{
    return d->frm.form();
}

/*!
    \property Q3DataBrowser::readOnly
    \brief whether the browser is read-only

    The default is false, i.e. data can be edited. If the data browser
    is read-only, no database edits will be allowed.
*/

void Q3DataBrowser::setReadOnly(bool active)
{
    d->readOnly = active;
}

bool Q3DataBrowser::isReadOnly() const
{
    return d->readOnly;
}

void Q3DataBrowser::setConfirmEdits(bool confirm)
{
    d->dat.setConfirmEdits(confirm);
}

/*!
    \property Q3DataBrowser::confirmInsert
    \brief whether the data browser confirms insertions

    If this property is true, the browser confirms insertions,
    otherwise insertions happen immediately.

    \sa confirmCancels() confirmEdits() confirmUpdate() confirmDelete() confirmEdit()
*/

void Q3DataBrowser::setConfirmInsert(bool confirm)
{
    d->dat.setConfirmInsert(confirm);
}

/*!
    \property Q3DataBrowser::confirmUpdate
    \brief whether the browser confirms updates

    If this property is true, the browser confirms updates, otherwise
    updates happen immediately.

    \sa confirmCancels() confirmEdits() confirmInsert() confirmDelete() confirmEdit()
*/

void Q3DataBrowser::setConfirmUpdate(bool confirm)
{
    d->dat.setConfirmUpdate(confirm);
}

/*!
    \property Q3DataBrowser::confirmDelete
    \brief whether the browser confirms deletions

    If this property is true, the browser confirms deletions,
    otherwise deletions happen immediately.

    \sa confirmCancels() confirmEdits() confirmUpdate() confirmInsert() confirmEdit()
*/

void Q3DataBrowser::setConfirmDelete(bool confirm)
{
    d->dat.setConfirmDelete(confirm);