deleteitemfromfirstcatalog.java

这是一个超市管理系统

package file2;
import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
public class DeleteItemFromFirstCatalog extends JPanel implements ActionListener{
	private DBConnection con=null;//声明数据库连接组件
	private JComboBox comboBox=null;
	private JButton delete=null;
	private JButton reset=null;
	private JPanel comboBoxPane=null;
	private JPanel buttonsPane=null;
	public DeleteItemFromFirstCatalog(){
		try{
			delete=new JButton("删除");
			reset=new JButton("重置");
			con=new DBConnection();
			String queryStr="select* from First_Catalog ";
			ResultSet rs=con.executeSelect(queryStr);
			int size=0;
			while(rs.next()){
				size++;
			}
			String[] data=new String[size+1];
			data[0]="请选择商品大类:";
			int count=1;
			rs=null;
			rs=con.executeSelect(queryStr);
			while(rs.next()){
				int ID=rs.getInt(1);
				String name=rs.getString(2);
				data[count++]=name;
			}
			comboBox=new JComboBox(data);
			comboBox.setSelectedIndex(0);
			comboBoxPane=new JPanel();
			comboBoxPane.add(comboBox,BorderLayout.CENTER);
			buttonsPane=new JPanel();
			buttonsPane.setLayout(new FlowLayout(FlowLayout.CENTER));
			buttonsPane.add(delete);
			buttonsPane.add(reset);
			this.add(comboBox,BorderLayout.NORTH);
			this.add(buttonsPane,BorderLayout.CENTER);
			delete.addActionListener(this);
			reset.addActionListener(this);
			if(size==0){
				JOptionPane.showMessageDialog(null, "数据库中没有任何商品大类!", "提示", JOptionPane.ERROR_MESSAGE);
				delete.setEnabled(false);
				reset.setEnabled(false);
				return;
			}
		}catch(Exception e){
			//e.printStackTrace();
			JOptionPane.showMessageDialog(null, "发生错误!", "提示", JOptionPane.ERROR_MESSAGE);
			return;
		}
		
	}
	public void actionPerformed(ActionEvent e){
		if(e.getSource()==reset){
			comboBox.setSelectedIndex(0);
			return;
		}
		if(e.getSource()==delete){
			try{
				String name=(String)comboBox.getSelectedItem();
				if(name.equals("请选择商品大类:")){
					JOptionPane.showMessageDialog(null, "您没有选择商品大类!", "提示", JOptionPane.ERROR_MESSAGE);
					return;
				}
				int confirm=JOptionPane.showConfirmDialog(null,"您确认要删除 "+name+" 吗?","确认",JOptionPane.YES_NO_OPTION);
				if(confirm==JOptionPane.YES_OPTION){
					String queryStr1="select First_ID from First_Catalog where First_name='"+name+"'";
					ResultSet set1=con.executeSelect(queryStr1);
					int ID=0;
					if(set1.next()){
						ID=set1.getInt(1);
					}
					String deleteStr1="delete from First_Catalog where First_name='"+name+"'";
					con.executeDML(deleteStr1);
					//删除Second_Catalog 表中的相应记录
					String queryStr3="select Second_ID from Second_Catalog where To_First_ID="+
					ID;
					ResultSet set3=con.executeSelect(queryStr3);
					while(set3.next()){
						String queryStr2="select Third_ID from Third_Catalog where To_Second_ID="+set3.getInt(1);
						ResultSet set4=con.executeSelect(queryStr2);
						while(set4.next()){
							//JOptionPane.showMessageDialog(null, "Third_Catalog中存在记录!", "提示", JOptionPane.INFORMATION_MESSAGE);
							String queryStr4="select* from operationRecord where To_Third_ID="+set4.getInt(1);
							ResultSet set5=con.executeSelect(queryStr4);
							while(set5.next()){
								con.executeDML("delete from operationRecord where To_Third_ID="+set4.getInt(1));
								//JOptionPane.showMessageDialog(null, "从operationRecord表中删除记录成功!", "提示", JOptionPane.INFORMATION_MESSAGE);
								//continue;
							}
							con.executeDML("delete from Third_Catalog where To_Second_ID="+set3.getInt(1));
							//JOptionPane.showMessageDialog(null, "operationRecord没有相应记录!", "提示", JOptionPane.INFORMATION_MESSAGE);
						}
						con.executeDML("delete from  Second_ID from Second_Catalog where To_First_ID="+
								ID);
					}
					comboBox.setSelectedIndex(0);
					JOptionPane.showMessageDialog(null, "删除成功!", "提示", JOptionPane.INFORMATION_MESSAGE);
					return;
				}
				comboBox.setSelectedIndex(0);
				return;
			}catch(Exception excep){
				excep.printStackTrace();
				JOptionPane.showMessageDialog(null, "发生错误!", "提示", JOptionPane.ERROR_MESSAGE);
				return;
			}
		}
	}
			
}