android 数据库用sql语句的 crud

来源：互联网发布：mysql 最近一条记录编辑：程序博客网时间：2024/04/27 01:25
package com.itheima.dao;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import com.itheima.db.PersonSQLiteOpenHelper;import com.itheima.domain.Person;public class PersonDao {private PersonSQLiteOpenHelper helper;/** *在构造方法里面完成helper的初始化 */public PersonDao(Context context){helper = new PersonSQLiteOpenHelper(context);}/** * 添加一条记录 * @param name * @param nunber */public void add(String name,String number){SQLiteDatabase  db = helper.getWritableDatabase();String sql = "insert into person values(?,?)";db.execSQL(sql,new Object[]{name,number});db.close();}/* * 查询记录是否存在； */public boolean find(String name){SQLiteDatabase db = helper.getReadableDatabase();Cursor rs = db.rawQuery("select * from person where name = ?", new String[]{name});boolean result = rs.moveToNext();rs.close();db.close();return result;}/** * 修改 */public void update(String name,String number){SQLiteDatabase db = helper.getWritableDatabase();db.execSQL(" update person set number = ? where name = ?",new Object[]{number,name});db.close();}/** * 删除一条记录 * @param name */public void delete(String name){SQLiteDatabase db = helper.getWritableDatabase();db.execSQL("delete from person where name = ?",new Object[]{name});db.close();}//返回全部的数据库信息public List<Person> getAll(){SQLiteDatabase db =helper.getReadableDatabase();Cursor rs = db.rawQuery("select * from person",null);List<Person> list = new ArrayList<Person>();while(rs.moveToNext()){int id = rs.getInt(1);String name = rs.getString(2);String number = rs.getString(rs.getColumnIndex("number"));Person p = new Person();p.setId(id);p.setName(name);p.setNumber(number);list.add(p);}rs.close();db.close();return list;}}
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