Sqlite数据库

数据库帮助类

package com.example.sqlite;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class MySqlite extends SQLiteOpenHelper {

 public MySqlite(Context context) {
  super(context, "baiye.db", null, 1);
  // TODO Auto-generated constructor stub
 }

 @Override
 public void onCreate(SQLiteDatabase db) {
  // TODO Auto-generated method stub
  db.execSQL("create table classroom(id integer primary key autoincrement,name varchar(20),num integer(11));");

 }

 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  // TODO Auto-generated method stub

 }

}

SqLiteDao封装操作数据库的方法

package com.example.sqliteDao;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.example.bean.User;
import com.example.sqlite.MySqlite;

public class SqLiteDao {
 
 private SQLiteDatabase db;

 public SqLiteDao(Context context){
  MySqlite msl=new MySqlite(context);
  db=msl.getWritableDatabase();
 }
 //添加
 public void add(String name,int num){
  db.execSQL("insert into classroom(name,num) values(?,?);", new Object[]{name,num});
 }
 //删除
 public void delete(int id){
  db.execSQL("delete from classroom where id=?;", new Object[]{id});
 }
 //修改
 public void update(String name,int id){
  db.execSQL("update classroom set name=? where id=?;", new Object[]{name,id});
 }
 public List<User> query(){
  Cursor cursor=db.rawQuery("select * from classroom ", null);
  List<User> lu=new ArrayList<User>();
  while(cursor.moveToNext()){
   lu.add(new User(cursor.getString(cursor.getColumnIndex("name")), cursor.getInt(cursor.getColumnIndex("id"))));
   
  }
  return lu;
 }
}