我正在尝试更新 JAVA 代码上数据库的值，但是当我尝试这样做时，它告诉我“主键的重复条目（nameOfSomething）”；即使 PK 不存在，也会给我这个错误，我不知道为什么。欢迎所有帮助；如果需要更多代码，我很乐意添加它。提前致谢。/**SO THE NEW ERROR WOULD BE ON THE IF/ELSE STATEMENT, WHICH IS TRHOWING THE ELSE, THAT SAYS "DATA WAS NOT UPDATED".*/JButton btnUpdate = new JButton("Update");        btnUpdate.addActionListener(new ActionListener() {            public void actionPerformed(ActionEvent e) {                String petname = txtName.getText();                String petphoto = txtPhoto.getText();                String pettype = txtType.getText();                String color = txtColor.getText();                int gender = Integer.parseInt(txtGender.getText());                int isSterilized = Integer.parseInt(txtSterilized.getText());                //DATE                String pedigree = txtPedigree.getText();                DateFormat df = new SimpleDateFormat("yyyy-MM-dd");                String date_entry = df.format(datePicker.getDate());                //END                String vaccine1 = txtVaccine1.getText();                String vaccine2 = txtVaccine2.getText();                String vaccine3 = txtVaccine3.getText();                Connection conn = null;                PreparedStatement pstmt = null;                try {                    Class.forName("com.mysql.jdbc.Driver");                    conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/refugio","root","2797");                    pstmt = conn.prepareStatement("UPDATE PETS SET PETPHOTO=?, PETTYPE=?, COLOR=?,GENDER=?,ISSTERILIZED=?,PEDIGREE=?,DATE_ENTRY=?,"                            + "VACCINE1=?,VACCINE2=?,VACCINE3=? WHERE PETNAME=?"); //NEW CHANGE HERE                }            }        });