sqlite增删改查（二）

使用sqlite自带的crud方法操作数据库，不赞成使用，因为效率没直接操作sql语句高

所以只把例子贴出来

package com.tjp.service;

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

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

import com.tjp.model.Person;

public class OtherPersonService {

    private DBOpenHelp openHelp=null;
    private Context context;
    
    
    public OtherPersonService(Context context) {
        this.context = context;
        openHelp=new DBOpenHelp(context);
    }

    public void save(Person person){
        SQLiteDatabase database= openHelp.getWritableDatabase();//对数据要更改,该方法以读和写的方式打开数据库,有缓存功能
        //database.execSQL("insert into person(name) values(?)",new Object[]{person.getName()});
        ContentValues values=new ContentValues();
        values.put("name", person.getName());
        database.insert("person", null, values);//不管有没有数据都想数据库里面保存数据,
        //database.insert("person", "name", null);//如果没有给定第三个字段或第三个参数个数为0个，那个就要指定一个空值字段
    }
    
    public void update(Person person){
        SQLiteDatabase database= openHelp.getWritableDatabase();
        //database.execSQL("update person set name=? where personid=?",new Object[]{person.getName(),person.getPersonId()});
        ContentValues values=new ContentValues();
        values.put("name", person.getName());
        database.update("person", values, "personid=?", new String[]{String.valueOf(person.getPersonId())});
    }
    
    public void delete(int personId){
        SQLiteDatabase database= openHelp.getWritableDatabase();
        //database.execSQL("delete from person where personid=?",new Object[]{personId});
        database.delete("person", "personid=?", new String[]{String.valueOf(personId)});
    }
    
    public Person find(int personId){
        SQLiteDatabase database= openHelp.getWritableDatabase();
        Person person=null;
        //Cursor cursor= database.rawQuery("select * from person where personid=?", new String[]{String.valueOf(personId).toString()});
        Cursor cursor=database.query("person", new String[]{"personid","name"}, 
                "personid=?", new String[]{String.valueOf(personId)}, null, null, null);
        if(cursor.moveToFirst()){//如果移动成功了表示存在
            int personIda =cursor.getInt(cursor.getColumnIndex("personid"));
            String name=cursor.getString(cursor.getColumnIndex("name"));
            person=new Person(personIda,name);
        }
        cursor.close();
        return person;
    }
    
    public List<Person> getScrollDate(int offerset,int maxResult){
        List<Person> persons=new ArrayList<Person>();
        SQLiteDatabase database= openHelp.getWritableDatabase();
        //String sql="select * from person limit ?,?";
        //Cursor cursor= database.rawQuery(sql, new String[]{String.valueOf(offerset),String.valueOf(maxResult)});
    
        Cursor cursor=database.query("person", null, null, null, null, null, null, offerset+","+maxResult);
        while(cursor.moveToNext()){
            int personIda =cursor.getInt(cursor.getColumnIndex("personid"));
            String name=cursor.getString(cursor.getColumnIndex("name"));
            Person person=new Person(personIda,name);
            persons.add(person);
        }
        return persons;
    }
    
    public long getCount(){
        SQLiteDatabase database= openHelp.getWritableDatabase();
        //Cursor cursor= database.rawQuery("select count(*) from person", null);
        Cursor cursor=database.query("person", new String[]{"count(*)"}, null, null, null, null, null);
        cursor.moveToFirst();
        int count=cursor.getInt(0);
        cursor.close();
        return count;
    }
}

当数据库更新的时候只要把版本号更新就会执行onUpgrade