android数据库使用系统封装的api实现SQLite数据库的增删改查

代码如下

package com.cwj.sqlite825.dao;

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

import com.cwj.sqlite825.PersonSQLiteOpenHelper;

public class PersonDao2 {
PersonSQLiteOpenHelper sqlHelper=null;
public PersonDao2(Context context)
{
sqlHelper=new PersonSQLiteOpenHelper(context, "cwj.db", null, 1);
}
public long addRecord(String name,String number)
{
SQLiteDatabase db = sqlHelper.getWritableDatabase();
ContentValues values=new ContentValues();
values.put("name", name);
values.put("number", number);
//-1表示添加失败
long res=db.insert("person", null, values);
db.close();
return res;
}
public String findRecord(String name)
{

String number="";
SQLiteDatabase db = sqlHelper.getReadableDatabase();
Cursor cursor=db.query("person", null, "name=?", new String[]{name}, null, null, null);
if(cursor.moveToNext()){
number=cursor.getString(cursor.getColumnIndex("number"));
}
cursor.close();
db.close();
return number;
}
public int updateNumberByName(String name,String number)
{
SQLiteDatabase db = sqlHelper.getWritableDatabase();
ContentValues values=new ContentValues();
values.put("number", number);
int res=db.update("person", values, "name=?", new String[]{name});
db.close();
return res;
}
public int delete(String name)
{
SQLiteDatabase db = sqlHelper.getWritableDatabase();
int res=db.delete("person", "name=?", new String[]{name});
return res;
}
}