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彻底改进分页算法

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feiyangqingyun
2021-04-27 07:43:21 +08:00
parent d1d9daa36f
commit 73035cd722
8 changed files with 250 additions and 239 deletions
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332
dbpage/dbpage.cpp
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@@ -115,11 +115,13 @@ void DbCountThread::select()
{
//计算用时
QDateTime dtStart = QDateTime::currentDateTime();
int count = 0;
QSqlQuery query(QSqlDatabase::database(connName));
query.exec(sql);
query.next();
int count = query.value(0).toUInt();
if (query.exec(sql)) {
if (query.next()) {
count = query.value(0).toUInt();
}
}
QDateTime dtEnd = QDateTime::currentDateTime();
double msec = dtStart.msecsTo(dtEnd);
@@ -127,40 +129,26 @@ void DbCountThread::select()
}
QScopedPointer<DbPage> DbPage::self;
DbPage *DbPage::Instance()
{
if (self.isNull()) {
static QMutex mutex;
QMutexLocker locker(&mutex);
if (self.isNull()) {
self.reset(new DbPage);
}
}
return self.data();
}
DbPage::DbPage(QObject *parent) : QObject(parent)
{
startIndex = 0;
queryModel = new SqlQueryModel;
pageCurrent = 1;
pageCount = 0;
resultCount = 0;
resultCurrent = 0;
pageTotal = 0;
recordsTotal = 0;
recordsPerpage = 0;
labPageCount = 0;
labPageTotal = 0;
labPageCurrent = 0;
labResultCount = 0;
labResultCurrent = 0;
labResult = 0;
labInfo = 0;
labRecordsTotal = 0;
labRecordsPerpage = 0;
labSelectTime = 0;
labSelectInfo = 0;
tableView = 0;
btnFirst = 0;
btnPre = 0;
btnPrevious = 0;
btnNext = 0;
btnLast = 0;
@@ -169,9 +157,9 @@ DbPage::DbPage(QObject *parent) : QObject(parent)
dbType = DbType_Sqlite;
pageCurrent = 0;
pageCount = 0;
resultCount = 0;
resultCurrent = 30;
pageTotal = 0;
recordsTotal = 0;
recordsPerpage = 30;
tableName = "";
selectColumn = "*";
@@ -238,24 +226,30 @@ void DbPage::bindData(const QString &sql)
labPageCurrent->setText(QString("第 %1 页").arg(pageCurrent));
}
if (labPageCount != 0) {
labPageCount->setText(QString("共 %1 页").arg(pageCount));
if (labPageTotal != 0) {
labPageTotal->setText(QString("共 %1 页").arg(pageTotal));
}
if (labResultCount != 0) {
labResultCount->setText(QString("共 %1 条").arg(resultCount));
if (labRecordsTotal != 0) {
labRecordsTotal->setText(QString("共 %1 条").arg(recordsTotal));
}
if (labResultCurrent != 0) {
labResultCurrent->setText(QString("每页 %1 条").arg(resultCurrent));
if (labRecordsPerpage != 0) {
labRecordsPerpage->setText(QString("每页 %1 条").arg(recordsPerpage));
}
if (labInfo != 0) {
labInfo->setText(QString("共 %1 条 每页 %2 条 共 %3 页 第 %4 页").arg(resultCount).arg(resultCurrent).arg(pageCount).arg(pageCurrent));
if (labSelectInfo != 0) {
//labSelectInfo->setText(QString("共 %1 条 每页 %2 条 共 %3 页 第 %4 页").arg(recordsTotal).arg(recordsPerpage).arg(pageTotal).arg(pageCurrent));
labSelectInfo->setText(QString("第 %1 页 每页 %2 条 共 %3 页 共 %4 条").arg(pageCurrent).arg(recordsPerpage).arg(pageTotal).arg(recordsTotal));
}
//发送结果信号
emit receivePage(pageCurrent, pageCount, resultCount, resultCurrent);
if (recordsTotal != recordsPerpage) {
emit receivePage(pageCurrent, pageTotal, recordsTotal, recordsPerpage);
//qDebug() << TIMEMS << startIndex << pageCurrent << pageTotal << recordsTotal << recordsPerpage;
}
changeBtnEnable();
}
QString DbPage::getPageSql()
@@ -263,14 +257,14 @@ QString DbPage::getPageSql()
//组织分页SQL语句,不同的数据库分页语句不一样
QString sql = QString("select %1 from %2 %3 order by %4").arg(selectColumn).arg(tableName).arg(whereSql).arg(orderSql);
if (dbType == DbType_PostgreSQL || dbType == DbType_KingBase) {
sql = QString("%1 limit %3 offset %2;").arg(sql).arg(startIndex).arg(resultCurrent);
sql = QString("%1 limit %3 offset %2;").arg(sql).arg(startIndex).arg(recordsPerpage);
} else if (dbType == DbType_SqlServer) {
//取第m条到第n条记录：select top (n-m+1) id from tablename where id not in (select top m-1 id from tablename)
//sql = QString("select %1 from %2 %3 order by %4").arg(selectColumn).arg(tableName).arg(whereSql).arg(orderSql);
} else if (dbType == DbType_Oracle) {
//暂时没有找到好办法
} else {
sql = QString("%1 limit %2,%3;").arg(sql).arg(startIndex).arg(resultCurrent);
sql = QString("%1 limit %2,%3;").arg(sql).arg(startIndex).arg(recordsPerpage);
}
return sql;
@@ -278,120 +272,46 @@ QString DbPage::getPageSql()
void DbPage::slot_receiveCount(quint32 count, double msec)
{
if (labResult != 0) {
labResult->setText(QString("查询用时 %1 秒").arg(QString::number(msec / 1000, 'f', 3)));
if (labSelectTime != 0) {
labSelectTime->setText(QString("查询用时 %1 秒").arg(QString::number(msec / 1000, 'f', 3)));
}
resultCount = count;
int yushu = resultCount % resultCurrent;
recordsTotal = count;
int yushu = recordsTotal % recordsPerpage;
//不存在余数,说明是整行,例如300%5==0
if (yushu == 0) {
if (resultCount > 0 && resultCount < resultCurrent) {
pageCount = 1;
if (recordsTotal > 0 && recordsTotal < recordsPerpage) {
pageTotal = 1;
} else {
pageCount = resultCount / resultCurrent;
pageTotal = recordsTotal / recordsPerpage;
}
} else {
pageCount = (resultCount / resultCurrent) + 1;
}
//2014-10-9增加翻页按钮可用不可用处理,如果只有一页数据,则翻页按钮不可用
if (pageCount <= 1) {
btnFirst->setEnabled(false);
btnLast->setEnabled(false);
btnNext->setEnabled(false);
btnPre->setEnabled(false);
} else {
btnFirst->setEnabled(true);
btnLast->setEnabled(true);
btnNext->setEnabled(true);
btnPre->setEnabled(true);
pageTotal = (recordsTotal / recordsPerpage) + 1;
}
bindData(getPageSql());
}
void DbPage::first()
{
if (pageCount > 1) {
startIndex = 0;
pageCurrent = 1;
bindData(getPageSql());
btnLast->setEnabled(true);
btnNext->setEnabled(true);
}
btnFirst->setEnabled(false);
btnPre->setEnabled(false);
}
void DbPage::previous()
{
if (pageCurrent > 1) {
pageCurrent--;
startIndex -= resultCurrent;
bindData(getPageSql());
btnLast->setEnabled(true);
btnNext->setEnabled(true);
}
if (pageCurrent == 1) {
btnFirst->setEnabled(false);
btnPre->setEnabled(false);
}
}
void DbPage::next()
{
if (pageCurrent < pageCount) {
pageCurrent++;
startIndex += resultCurrent;
bindData(getPageSql());
btnFirst->setEnabled(true);
btnPre->setEnabled(true);
}
if (pageCurrent == pageCount) {
btnLast->setEnabled(false);
btnNext->setEnabled(false);
}
}
void DbPage::last()
{
if (pageCount > 0) {
startIndex = (pageCount - 1) * resultCurrent;
pageCurrent = pageCount;
bindData(getPageSql());
btnFirst->setEnabled(true);
btnPre->setEnabled(true);
}
btnLast->setEnabled(false);
btnNext->setEnabled(false);
}
//设置显示数据的表格控件,当前翻页信息的标签控件等
void DbPage::setControl(QTableView *tableView,
QLabel *labPageCount, QLabel *labPageCurrent,
QLabel *labResultCount, QLabel *labResultCurrent,
QLabel *labResult, QLabel *labInfo,
QAbstractButton *btnFirst, QAbstractButton *btnPre,
QLabel *labPageTotal, QLabel *labPageCurrent,
QLabel *labRecordsTotal, QLabel *labRecordsPerpage,
QLabel *labSelectTime, QLabel *labSelectInfo,
QAbstractButton *btnFirst, QAbstractButton *btnPrevious,
QAbstractButton *btnNext, QAbstractButton *btnLast,
const QString &countName, const QString &connName)
{
this->tableView = tableView;
this->labPageCount = labPageCount;
this->labPageTotal = labPageTotal;
this->labPageCurrent = labPageCurrent;
this->labResultCount = labResultCount;
this->labResultCurrent = labResultCurrent;
this->labResult = labResult;
this->labInfo = labInfo;
this->labRecordsTotal = labRecordsTotal;
this->labRecordsPerpage = labRecordsPerpage;
this->labSelectTime = labSelectTime;
this->labSelectInfo = labSelectInfo;
this->btnFirst = btnFirst;
this->btnPre = btnPre;
this->btnPrevious = btnPrevious;
this->btnNext = btnNext;
this->btnLast = btnLast;
@@ -399,13 +319,39 @@ void DbPage::setControl(QTableView *tableView,
this->connName = connName;
this->tableView->setSelectionBehavior(QAbstractItemView::SelectRows);
if (btnFirst == 0 || btnPrevious == 0 || btnNext == 0 || btnLast == 0) {
return;
}
//挂载翻页按钮事件
connect(btnFirst, SIGNAL(clicked()), this, SLOT(first()));
connect(btnPre, SIGNAL(clicked()), this, SLOT(previous()));
connect(btnPrevious, SIGNAL(clicked()), this, SLOT(previous()));
connect(btnNext, SIGNAL(clicked()), this, SLOT(next()));
connect(btnLast, SIGNAL(clicked()), this, SLOT(last()));
}
void DbPage::setControl(QTableView *tableView,
QLabel *labPageTotal, QLabel *labPageCurrent,
QLabel *labRecordsTotal, QLabel *labRecordsPerpage,
QLabel *labSelectTime, QLabel *labSelectInfo,
const QString &countName, const QString &connName)
{
setControl(tableView, labPageTotal, labPageCurrent, labRecordsTotal, labRecordsPerpage, labSelectTime, labSelectInfo, 0, 0, 0, 0, countName, connName);
}
void DbPage::setControl(QTableView *tableView,
QAbstractButton *btnFirst, QAbstractButton *btnPrevious,
QAbstractButton *btnNext, QAbstractButton *btnLast,
const QString &countName, const QString &connName)
{
setControl(tableView, 0, 0, 0, 0, 0, 0, btnFirst, btnPrevious, btnNext, btnLast, countName, connName);
}
void DbPage::setControl(QTableView *tableView, const QString &countName, const QString &connName)
{
setControl(tableView, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, countName, connName);
}
void DbPage::setConnName(const QString &connName)
{
this->connName = connName;
@@ -436,9 +382,9 @@ void DbPage::setWhereSql(const QString &whereSql)
this->whereSql = whereSql;
}
void DbPage::setResultCurrent(int resultCurrent)
void DbPage::setRecordsPerpage(int recordsPerpage)
{
this->resultCurrent = resultCurrent;
this->recordsPerpage = recordsPerpage;
}
void DbPage::setColumnNames(const QList<QString> &columnNames)
@@ -481,45 +427,62 @@ void DbPage::setInsertColumnWidth(int insertColumnWidth)
this->insertColumnWidth = insertColumnWidth;
}
void DbPage::changeBtnEnable()
{
if (btnFirst == 0 || btnPrevious == 0 || btnNext == 0 || btnLast == 0) {
return;
}
//下面默认对上一页下一页按钮禁用
//也可以取消注释对第一页末一页同样处理
//因为到了第一页就可以不必再单击第一页和上一页
if (pageTotal <= 1) {
//如果只有一页数据则翻页按钮不可用
btnFirst->setEnabled(false);
btnLast->setEnabled(false);
btnPrevious->setEnabled(false);
btnNext->setEnabled(false);
} else {
//判断是否在首页末页禁用按钮
bool first = (pageCurrent == 1);
bool last = (pageCurrent == pageTotal);
btnFirst->setEnabled(!first);
btnLast->setEnabled(!last);
btnPrevious->setEnabled(!first);
btnNext->setEnabled(!last);
}
}
void DbPage::select()
{
//重置开始索引
startIndex = 0;
pageCurrent = 1;
pageTotal = 1;
changeBtnEnable();
//假设只有一页
slot_receiveCount(resultCurrent, 0);
//全部禁用按钮,文本显示正在查询...
btnFirst->setEnabled(false);
btnLast->setEnabled(false);
btnNext->setEnabled(false);
btnPre->setEnabled(false);
slot_receiveCount(recordsPerpage, 0);
//文本显示正在查询...
QString info = "正在查询...";
if (labInfo != 0) {
labInfo->setText(info);
if (labSelectInfo != 0) {
labSelectInfo->setText(info);
}
if (labPageCurrent != 0) {
labPageCurrent->setText(info);
}
if (labPageCount != 0) {
labPageCount->setText(info);
if (labPageTotal != 0) {
labPageTotal->setText(info);
}
if (labResultCount != 0) {
labResultCount->setText(info);
if (labRecordsTotal != 0) {
labRecordsTotal->setText(info);
}
if (labResultCurrent != 0) {
labResultCurrent->setText(info);
if (labRecordsPerpage != 0) {
labRecordsPerpage->setText(info);
}
if (labResult != 0) {
labResult->setText(info);
if (labSelectTime != 0) {
labSelectTime->setText(info);
}
//开始分页绑定数据前,计算好总数据量以及行数
@@ -541,3 +504,54 @@ void DbPage::select()
dbCountThread->select();
#endif
}
void DbPage::selectPage(int page)
{
//必须小于总页数+不是当前页
if (page >= 1 && page <= pageTotal && page != pageCurrent) {
//计算指定页对应开始的索引
startIndex = (page - 1) * recordsPerpage;
pageCurrent = page;
bindData(getPageSql());
}
}
void DbPage::first()
{
//当前页不是第一页才能切换到第一页
if (pageTotal > 1 && pageCurrent != 1) {
startIndex = 0;
pageCurrent = 1;
bindData(getPageSql());
}
}
void DbPage::previous()
{
//当前页不是第一页才能上一页
if (pageCurrent > 1) {
pageCurrent--;
startIndex -= recordsPerpage;
bindData(getPageSql());
}
}
void DbPage::next()
{
//当前页小于总页数才能下一页
if (pageCurrent < pageTotal) {
pageCurrent++;
startIndex += recordsPerpage;
bindData(getPageSql());
}
}
void DbPage::last()
{
//当前页不是末尾页才能切换到末尾页
if (pageTotal > 1 && pageCurrent != pageTotal) {
startIndex = (pageTotal - 1) * recordsPerpage;
pageCurrent = pageTotal;
bindData(getPageSql());
}
}