Python&MySQL&PyQt

2022-08-07 11:18:44

环境：

Python2.7+MySQL5.6+PyQt4

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简单的图形化界面操作数据库：模仿写一个类似于navicat完毕可视化检索功能的界面，利用PyQt可视化编程高速完毕界面设计，这点比Tkinter设计要简单；

1.利用PyQt进行界面设计：

打开PyQt，新建，选择Main Window，选择左端的控件拖动完毕界面的设计，选中元素。能够从右側查看元素的信息以及改动其属性值，以下贴上设计图：

在设计界面中选中元素双击。能够改动其属性名。加入text。改变显示字符格式等；

2.设计完毕后，保存为.ui文件。接下来将其转换为.py文件：

打开cmd：进入PyQt安装文件夹：

Lib\site-packages\PyQt4\uic>

键入命令格式：

python pyuic.py -o .py文件文件夹+文件名称 .ui文件文件夹+文件名称

我保存的.ui文件放在D盘根文件夹中，生成的.py文件命名为nihao0.py

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3.打开Python执行.py，查看界面

在原有的代码基础上加入下列代码：

import sys

class MyWindow(QtGui.QMainWindow,Ui_MainWindow):#PyQt生产的是一个叫做Ui_MainWindow的类，仅仅须要放在一个框架下画出来就可以。

    def __init__(self):

        super(MyWindow,self).__init__()

        self.setupUi(self)

if __name__=="__main__":

    app=QtGui.QApplication(sys.argv)#建立一个app，把框架放在这个app中执行

    app.aboutToQuit.connect(app.deleteLater)

    myshow=MyWindow()

    myshow.show()

    sys.exit(app.exec_())#也能够写成app.exec_() sys.exit(0)，前者是循环整个界面，后者是退出app

执行结果：

这时我们得到了一个我们想得到的界面。仅仅须要往这个界面中加入各种事件就可以；

4.动态生成SQL语句——准备

新建数据库mysql。和表格students,表格的属性为

DDL为：

CREATE TABLE `students` (

  `Sid` char(10) NOT NULL,

  `Sname` char(10) DEFAULT NULL,

  `Sage` int(3) DEFAULT NULL,

  `Ssex` char(4) DEFAULT NULL,

  `Sclass` char(7) DEFAULT NULL,

  `Sdept` char(10) DEFAULT NULL,

  `Saddr` char(40) DEFAULT NULL,

  PRIMARY KEY (`Sid`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

先写好句柄：

sqlsting="select * from students where "

然后写一个clicked()事件。点击查询的时候，依据用户输入动态构造SQL语句

使用到的方法主要有：

是否选择复选框：checked()

读入输入：text()

5.动态生成SQL语句——字符串构造

构造技巧：

是否须要加and：假设前面已经有了原子公式，须要添加and，否则不加。使用一个flag就可以；

是否须要加引號：字符型须要加引號，数字不须要加。

数字类型须要先转换为字符类型：当为数字类型转换为字符型str()。推断数据类型type()，事实上能够不写，由于从界面返回的都是QtString类型的数据。

推断什么时候使用Like(字符串匹配问题%)：字符串方法.find("%")。返回值是第一个%出现的位置，假设%不存在。则返回-1；

6.界面显示问题

self.sql_out = QtGui.QTextBrowser(self.centralwidget)：显示框用法：

.setText(str)：清除原来数据。显示新的字符串

.append(str)：在末尾加入新的字符串

self.result_out = QtGui.QTableWidget(self.centralwidget)：表格框用法：

.setItem(i,j,newItem)：将newItem放在第i行，第j列。注意ij都从0開始；

newItem的声明格式为newItem = QtGui.QTableWidgetItem(str)，即在(i,j)位置显示str

注意QTableWidget仅仅能显示字符串，不能显示数字，全部在显示数据前，须要推断是否为数字：

解决方法：type()以及str()

7.数据库连接问题：

具体在Python&MySQL中已经讲述清除，能够作參考

8.贴上Python代码及执行结果：

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'D:/nihao.ui'

#

# Created: Fri Apr 01 15:28:59 2016

#      by: PyQt4 UI code generator 4.11.3

#

# WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

import sys

import MySQLdb

try:

    _fromUtf8 = QtCore.QString.fromUtf8

except AttributeError:

    def _fromUtf8(s):

        return s

try:

    _encoding = QtGui.QApplication.UnicodeUTF8

    def _translate(context, text, disambig):

        return QtGui.QApplication.translate(context, text, disambig, _encoding)

except AttributeError:

    def _translate(context, text, disambig):

        return QtGui.QApplication.translate(context, text, disambig)

class Ui_MainWindow(object):

    def setupUi(self, MainWindow):

        self.conn=MySQLdb.connect(

            host='localhost',

            user='root',

            passwd='',

            db='mysql',

            #

            charset='utf8',

        )

        self.cur=self.conn.cursor()

        self.sqlstring="select * from students where "

        MainWindow.setObjectName(_fromUtf8("MainWindow"))

        MainWindow.resize(760, 440)

        self.centralwidget = QtGui.QWidget(MainWindow)

        self.centralwidget.setObjectName(_fromUtf8("centralwidget"))

        self.frame = QtGui.QFrame(self.centralwidget)

        self.frame.setGeometry(QtCore.QRect(10, 10, 491, 121))

        self.frame.setFrameShape(QtGui.QFrame.StyledPanel)

        self.frame.setFrameShadow(QtGui.QFrame.Raised)

        self.frame.setObjectName(_fromUtf8("frame"))

        self.check_Sid = QtGui.QCheckBox(self.frame)

        self.check_Sid.setGeometry(QtCore.QRect(20, 10, 71, 16))

        self.check_Sid.setObjectName(_fromUtf8("check_Sid"))

        self.check_Sage = QtGui.QCheckBox(self.frame)

        self.check_Sage.setGeometry(QtCore.QRect(20, 70, 71, 16))

        self.check_Sage.setObjectName(_fromUtf8("check_Sage"))

        self.check_Sname = QtGui.QCheckBox(self.frame)

        self.check_Sname.setGeometry(QtCore.QRect(20, 40, 71, 16))

        self.check_Sname.setObjectName(_fromUtf8("check_Sname"))

        self.check_Ssex = QtGui.QCheckBox(self.frame)

        self.check_Ssex.setGeometry(QtCore.QRect(20, 100, 71, 16))

        self.check_Ssex.setObjectName(_fromUtf8("check_Ssex"))

        self.Sid = QtGui.QLineEdit(self.frame)

        self.Sid.setGeometry(QtCore.QRect(90, 10, 113, 16))

        self.Sid.setObjectName(_fromUtf8("Sid"))

        self.Sname = QtGui.QLineEdit(self.frame)

        self.Sname.setGeometry(QtCore.QRect(90, 40, 113, 16))

        self.Sname.setObjectName(_fromUtf8("Sname"))

        self.first_Sage = QtGui.QLineEdit(self.frame)

        self.first_Sage.setGeometry(QtCore.QRect(90, 70, 41, 16))

        self.first_Sage.setObjectName(_fromUtf8("first_Sage"))

        self.Ssex = QtGui.QLineEdit(self.frame)

        self.Ssex.setGeometry(QtCore.QRect(90, 100, 113, 16))

        self.Ssex.setObjectName(_fromUtf8("Ssex"))

        self.label = QtGui.QLabel(self.frame)

        self.label.setGeometry(QtCore.QRect(140, 70, 16, 16))

        self.label.setObjectName(_fromUtf8("label"))

        self.last_Sage = QtGui.QLineEdit(self.frame)

        self.last_Sage.setGeometry(QtCore.QRect(160, 70, 41, 16))

        self.last_Sage.setObjectName(_fromUtf8("last_Sage"))

        self.check_Sdept = QtGui.QCheckBox(self.frame)

        self.check_Sdept.setGeometry(QtCore.QRect(270, 40, 71, 16))

        self.check_Sdept.setObjectName(_fromUtf8("check_Sdept"))

        self.Sdept = QtGui.QLineEdit(self.frame)

        self.Sdept.setGeometry(QtCore.QRect(340, 40, 113, 16))

        self.Sdept.setObjectName(_fromUtf8("Sdept"))

        self.Sclass = QtGui.QLineEdit(self.frame)

        self.Sclass.setGeometry(QtCore.QRect(340, 10, 113, 16))

        self.Sclass.setObjectName(_fromUtf8("Sclass"))

        self.check_Sclass = QtGui.QCheckBox(self.frame)

        self.check_Sclass.setGeometry(QtCore.QRect(270, 10, 71, 16))

        self.check_Sclass.setObjectName(_fromUtf8("check_Sclass"))

        self.Saddr = QtGui.QLineEdit(self.frame)

        self.Saddr.setGeometry(QtCore.QRect(340, 70, 113, 16))

        self.Saddr.setObjectName(_fromUtf8("Saddr"))

        self.check_Saddr = QtGui.QCheckBox(self.frame)

        self.check_Saddr.setGeometry(QtCore.QRect(270, 70, 71, 16))

        self.check_Saddr.setObjectName(_fromUtf8("check_Saddr"))

        self.find = QtGui.QPushButton(self.frame)

        self.find.setGeometry(QtCore.QRect(380, 100, 75, 21))

        self.find.setObjectName(_fromUtf8("find"))

        self.sql_out = QtGui.QTextBrowser(self.centralwidget)

        self.sql_out.setGeometry(QtCore.QRect(10, 140, 740, 61))

        self.sql_out.setObjectName(_fromUtf8("sql_out"))

        self.result_out = QtGui.QTableWidget(self.centralwidget)

        self.result_out.setEditTriggers(QtGui.QAbstractItemView.NoEditTriggers)#不可编辑表格

        self.result_out.setGeometry(QtCore.QRect(10, 210, 740, 171))

        self.result_out.setObjectName(_fromUtf8("result_out"))

        self.result_out.setColumnCount(7)

        self.result_out.setRowCount(10)

        self.result_out.resizeColumnsToContents()

        self.result_out.resizeRowsToContents()

        item = QtGui.QTableWidgetItem()

        self.result_out.setHorizontalHeaderItem(0, item)

        item = QtGui.QTableWidgetItem()

        self.result_out.setHorizontalHeaderItem(1, item)

        item = QtGui.QTableWidgetItem()

        self.result_out.setHorizontalHeaderItem(2, item)

        item = QtGui.QTableWidgetItem()

        self.result_out.setHorizontalHeaderItem(3, item)

        item = QtGui.QTableWidgetItem()

        self.result_out.setHorizontalHeaderItem(4, item)

        item = QtGui.QTableWidgetItem()

        self.result_out.setHorizontalHeaderItem(5, item)

        item = QtGui.QTableWidgetItem()

        self.result_out.setHorizontalHeaderItem(6, item)

        self.result_out.horizontalHeader().setDefaultSectionSize(100)

        self.result_out.horizontalHeader().setMinimumSectionSize(25)

        self.result_out.verticalHeader().setDefaultSectionSize(30)

        self.pushButton_2 = QtGui.QPushButton(self.centralwidget)

        self.pushButton_2.setGeometry(QtCore.QRect(675, 390, 75, 21))

        self.pushButton_2.setObjectName(_fromUtf8("pushButton_2"))

        MainWindow.setCentralWidget(self.centralwidget)

        self.menubar = QtGui.QMenuBar(MainWindow)

        self.menubar.setGeometry(QtCore.QRect(0, 0, 509, 23))

        self.menubar.setObjectName(_fromUtf8("menubar"))

        MainWindow.setMenuBar(self.menubar)

        self.statusbar = QtGui.QStatusBar(MainWindow)

        self.statusbar.setObjectName(_fromUtf8("statusbar"))

        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)

        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):

        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))

        self.check_Sid.setText(_translate("MainWindow", "学号", None))

        self.check_Sage.setText(_translate("MainWindow", "年龄自", None))

        self.check_Sname.setText(_translate("MainWindow", "姓名", None))

        self.check_Ssex.setText(_translate("MainWindow", "性别", None))

        self.label.setText(_translate("MainWindow", "到", None))

        self.check_Sdept.setText(_translate("MainWindow", "系", None))

        self.check_Sclass.setText(_translate("MainWindow", "班级", None))

        self.check_Saddr.setText(_translate("MainWindow", "地址", None))

        self.find.setText(_translate("MainWindow", "查询", None))

        self.sql_out.setText(self.sqlstring)

        item = self.result_out.horizontalHeaderItem(0)

        item.setText(_translate("MainWindow", "Sid", None))

        item = self.result_out.horizontalHeaderItem(1)

        item.setText(_translate("MainWindow", "Sname ", None))

        item = self.result_out.horizontalHeaderItem(2)

        item.setText(_translate("MainWindow", "Sage", None))

        item = self.result_out.horizontalHeaderItem(3)

        item.setText(_translate("MainWindow", "Ssex", None))

        item = self.result_out.horizontalHeaderItem(4)

        item.setText(_translate("MainWindow", "Sclass", None))

        item = self.result_out.horizontalHeaderItem(5)

        item.setText(_translate("MainWindow", "Sdept", None))

        item = self.result_out.horizontalHeaderItem(6)

        item.setText(_translate("MainWindow", "Saddr", None))

        self.pushButton_2.setText(_translate("MainWindow", "退出", None))

    def mousePressEvent(self,event):

        if event.self.find()==QtCore.Qt.LeftButton:

            print "nihao"

    def buttonTest(self):

        temp_sqlstring=self.sqlstring

        is_first = True

        if self.check_Sid.isChecked():

            mystr = self.Sid.text()

            if is_first:

                is_first = False

                if mystr.find("%")==-1:

                    temp_sqlstring += "Sid = '" + self.Sid.text() + "'"

                else:

                    temp_sqlstring += "Sid like '" + self.Sid.text() + "'"

            else:

                if mystr.find("%")==-1:

                    temp_sqlstring += " and Sid = '" + self.Sid.text() + "'"

                else:

                    temp_sqlstring += " and Sid like '" + self.Sid.text() + "'"

        if self.check_Sname.isChecked():

            if is_first:

                mystr =self.Sname.text()

                is_first = False

                if mystr.find("%")==-1:

                    temp_sqlstring += "Sname = '" + self.Sname.text() + "'"

                else:

                    temp_sqlstring += "Sname like '" + self.Sname.text() + "'"

            else:

                if mystr.find("%")==-1:

                    temp_sqlstring += " and Sname = '" + self.Sname.text() + "'"

                else:

                    temp_sqlstring += " and Sname like '" + self.Sname.text() + "'"

        if self.check_Sage.isChecked():

            if is_first:

                is_first = False

                temp_sqlstring += "Sage >= " + self.first_Sage.text() +\

                " and Sage <= " + self.last_Sage.text()

            else:

                temp_sqlstring += " and Sage >= " + self.first_Sage.text() +\

                " and Sage <= " + self.last_Sage.text()

        if self.check_Ssex.isChecked():

            if is_first:

                is_first = False

                temp_sqlstring += "Ssex = '" + self.Ssex.text() + "'"

            else:

                temp_sqlstring += " and Ssex = '" + self.Ssex.text() + "'"

        if self.check_Sclass.isChecked():

            if is_first:

                mystr = self.Sclass.text()

                is_first = False

                if mystr.find("%")==-1:

                    temp_sqlstring += "Sclass = '" + self.Sclass.text() + "'"

                else:

                    temp_sqlstring += "Sclass like '" + self.Sclass.text() + "'"

            else:

                if mystr.find("%")==-1:

                    temp_sqlstring += " and Sclass = '" + self.Sclass.text() + "'"

                else:

                    temp_sqlstring += " and Sclass like '" + self.Sclass.text() + "'"

        if self.check_Sdept.isChecked():

            if is_first:

                mystr = self.Sdept.text()

                is_first = False

                if mystr.find("%")==-1:

                    temp_sqlstring += "Sdept = '" + self.Sdept.text() + "'"

                else:

                    temp_sqlstring += "Sdept like '" + self.Sdept.text() + "'"

            else:

                if mystr.find("%")==-1:

                    temp_sqlstring += " and Sdept = '" + self.Sdept.text() + "'"

                else:

                    temp_sqlstring += " and Sdept like '" + self.Sdept.text() + "'"

        if self.check_Saddr.isChecked():

            if is_first:

                mystr = self.Saddr.text()

                is_first = False

                if mystr.find("%")==-1:

                    temp_sqlstring += "Saddr = '" + self.Saddr.text() + "'"

                else:

                    temp_sqlstring +=" and Saddr like '" + self.Saddr.text() + "'"

            else:

                if mystr.find("%")==-1:

                    temp_sqlstring += " and Saddr = '" + self.Saddr.text() + "'"

                else:

                    temp_sqlstring +=" and Saddr like '" + self.Saddr.text() + "'"

        self.result_out.clearContents()#每一次查询时清除表格中信息

        if not(is_first):

            self.cur.execute(temp_sqlstring)

            k=0

            for i in self.cur:

                w=0

                for j in i:

                    if type(j)==long:

                        newItem = QtGui.QTableWidgetItem(str(j))

                    else:

                        newItem = QtGui.QTableWidgetItem(j)

                    self.result_out.setItem(k,w,newItem)

                    w += 1

                k +=1

        self.sql_out.setText("")

        self.sql_out.append(temp_sqlstring)

        print "find button pressed"

    def buttonExit(self):

        self.conn.commit()

        self.cur.close()

        self.conn.close()

        self.close()

    def keyPressEvent(self, e):

        if e.key() == QtCore.Qt.Key_Escape:

            self.buttonExit()

class MyWindow(QtGui.QMainWindow,Ui_MainWindow):

    def __init__(self):

        super(MyWindow,self).__init__()

        self.setupUi(self)

        self.connect(self.find, QtCore.SIGNAL('clicked()'), self.buttonTest)

        self.connect(self.pushButton_2,QtCore.SIGNAL('clicked()'),self.buttonExit)

if __name__=="__main__":

    app=QtGui.QApplication(sys.argv)

    app.aboutToQuit.connect(app.deleteLater)

    myshow=MyWindow()

    myshow.show()

    sys.exit(app.exec_())

    #app.exec_()

    #sys.exit(0)

注：执行前首先确保已经在MySQL中存在mysql数据库以及students表格。

执行结果：

因为原来设计的界面比較小。后来改变了各个控件的长宽；

这样就完毕的简单的界面化动态构造SQL语句，并将结果返回界面显示功能。

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