用pycharm制作一个学生管理系统，需要gui界面并能连接mySQL，全部代码

下面是一个使用PyQt5和MySQL实现的简单学生管理系统的完整代码：

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QHBoxLayout, QLabel, QLineEdit, QPushButton, QTableWidget, QTableWidgetItem
from PyQt5.QtSql import QSqlDatabase, QSqlQuery
from PyQt5.QtGui import QFont

class StudentManagementSystem(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('学生管理系统')
        self.resize(800, 600)
        self.font = QFont('Arial', 16)
        self.initUI()
        self.initDB()

    def initUI(self):
        # 初始化界面元素
        self.id_label = QLabel('学号')
        self.id_label.setFont(self.font)
        self.id_edit = QLineEdit()
        self.id_edit.setFont(self.font)

        self.name_label = QLabel('姓名')
        self.name_label.setFont(self.font)
        self.name_edit = QLineEdit()
        self.name_edit.setFont(self.font)

        self.gender_label = QLabel('性别')
        self.gender_label.setFont(self.font)
        self.gender_edit = QLineEdit()
        self.gender_edit.setFont(self.font)

        self.class_label = QLabel('班级')
        self.class_label.setFont(self.font)
        self.class_edit = QLineEdit()
        self.class_edit.setFont(self.font)

        self.add_button = QPushButton('添加')
        self.add_button.setFont(self.font)
        self.add_button.clicked.connect(self.addStudent)

        self.update_button = QPushButton('更新')
        self.update_button.setFont(self.font)
        self.update_button.clicked.connect(self.updateStudent)

        self.delete_button = QPushButton('删除')
        self.delete_button.setFont(self.font)
        self.delete_button.clicked.connect(self.deleteStudent)

        self.search_button = QPushButton('搜索')
        self.search_button.setFont(self.font)
        self.search_button.clicked.connect(self.searchStudent)

        self.table = QTableWidget()
        self.table.setColumnCount(4)
        self.table.setHorizontalHeaderLabels(['学号', '姓名', '性别', '班级'])
        self.table.setFont(self.font)

        # 设置布局
        id_layout = QHBoxLayout()
        id_layout.addWidget(self.id_label)
        id_layout.addWidget(self.id_edit)

        name_layout = QHBoxLayout()
        name_layout.addWidget(self.name_label)
        name_layout.addWidget(self.name_edit)

        gender_layout = QHBoxLayout()
        gender_layout.addWidget(self.gender_label)
        gender_layout.addWidget(self.gender_edit)

        class_layout = QHBoxLayout()
        class_layout.addWidget(self.class_label)
        class_layout.addWidget(self.class_edit)

        button_layout = QHBoxLayout()
        button_layout.addWidget(self.add_button)
        button_layout.addWidget(self.update_button)
        button_layout.addWidget(self.delete_button)
        button_layout.addWidget(self.search_button)

        input_layout = QVBoxLayout()
        input_layout.addLayout(id_layout)
        input_layout.addLayout(name_layout)
        input_layout.addLayout(gender_layout)
        input_layout.addLayout(class_layout)
        input_layout.addLayout(button_layout)

        main_layout = QVBoxLayout()
        main_layout.addLayout(input_layout)
        main_layout.addWidget(self.table)

        self.setLayout(main_layout)

    def initDB(self):
        # 初始化数据库连接
        self.db = QSqlDatabase.addDatabase('QMYSQL')
        self.db.setHostName('localhost')
        self.db.setDatabaseName('student')
        self.db.setUserName('root')
        self.db.setPassword('password')
        if not self.db.open():
            print('无法连接数据库')
            sys.exit(-1)

    def addStudent(self):
        # 添加学生信息
        query = QSqlQuery()
        query.prepare('INSERT INTO student (id, name, gender, class) VALUES (?, ?, ?, ?)')
        query.addBindValue(self.id_edit.text())
        query.addBindValue(self.name_edit.text())
        query.addBindValue(self.gender_edit.text())
        query.addBindValue(self.class_edit.text())
        if query.exec():
            self.clearInput()
            self.loadStudents()
        else:
            print('添加学生信息失败')

    def updateStudent(self):
        # 更新学生信息
        query = QSqlQuery()
        query.prepare('UPDATE student SET name=?, gender=?, class=? WHERE id=?')
        query.addBindValue(self.name_edit.text())
        query.addBindValue(self.gender_edit.text())
        query.addBindValue(self.class_edit.text())
        query.addBindValue(self.id_edit.text())
        if query.exec():
            self.clearInput()
            self.loadStudents()
        else:
            print('更新学生信息失败')

    def deleteStudent(self):
        # 删除学生信息
        query = QSqlQuery()
        query.prepare('DELETE FROM student WHERE id=?')
        query.addBindValue(self.id_edit.text())
        if query.exec():
            self.clearInput()
            self.loadStudents()
        else:
            print('删除学生信息失败')

    def searchStudent(self):
        # 搜索学生信息
        query = QSqlQuery()
        query.prepare('SELECT * FROM student WHERE id=?')
        query.addBindValue(self.id_edit.text())
        if query.exec():
            if query.next():
                self.name_edit.setText(query.value(1))
                self.gender_edit.setText(query.value(2))
                self.class_edit.setText(query.value(3))
            else:
                self.clearInput()
        else:
            print('搜索学生信息失败')

    def loadStudents(self):
        # 加载所有学生信息到表格中
        query = QSqlQuery()
        query.exec('SELECT * FROM student')
        self.table.setRowCount(0)
        while query.next():
            row = self.table.rowCount()
            self.table.insertRow(row)
            self.table.setItem(row, 0, QTableWidgetItem(str(query.value(0))))
            self.table.setItem(row, 1, QTableWidgetItem(query.value(1)))
            self.table.setItem(row, 2, QTableWidgetItem(query.value(2)))
            self.table.setItem(row, 3, QTableWidgetItem(query.value(3)))

    def clearInput(self):
        # 清空输入框
        self.id_edit.clear()
        self.name_edit.clear()
        self.gender_edit.clear()
        self.class_edit.clear()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    system = StudentManagementSystem()
    system.show()
    system.loadStudents()
    sys.exit(app.exec_())

这段代码实现了一个简单的学生管理系统，包括添加、删除、更新、搜索学生信息以及将所有学生信息加载到表格中的功能。在代码中还使用了PyQt5和MySQL进行界面设计和数据库操作。在使用之前，需要安装相应的库，例如：

pip install PyQt5 PyQt5-sql mysql-connector-python

同时，还需要创建一个名为`student`的MySQL数据库，并创建一个名为`student`的表，包含`id`、`name`、`gender`和`class`四个字段。在实际运行时，需要将代码中的数据库连接信息修改为实际的地址、用户名和密码。