SQLiteOpenHelper的使用

package com.zzxy.chenyb;

1 创建数据库辅助类，继承于SQLiteOpenHelper

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

public class DataBaseUtil extends SQLiteOpenHelper {

private static final String DATABASENAME="llh.db";

private static final int DATABASEVERSION=1;//版本号修改时，会执行onUpgrade方法

private static final String USER="user";

public DataBaseUtil(Context context){

super(context, DATABASENAME, null, DATABASEVERSION);

}

public DataBaseUtil(Context context, String name, CursorFactory factory,

int version) {

super(context, DATABASENAME, factory, DATABASEVERSION);

}

@Override

public void onCreate(SQLiteDatabase db) {

String sql="create table "+USER+" (" +

"ID INTEGER PRIMARY KEY" +

",NAME VARCHAR(50) NOT NULL" +

",PASSWORD VARCHAR(15) NOT NULL)";

db.execSQL(sql);

System.out.println("create user successfully...");

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

String sql="DROP TABLE IF EXISTS "+USER;

db.execSQL(sql);

this.onCreate(db);

System.out.println("drop user successfully...");

}

}

2 编写测试类，验证创建的数据库

SQLiteOpenHelper sqlite=new DataBaseUtil(LoginView.this);

sqlite.getWritableDatabase();

验证执行完成程序后，到指定的文件夹内寻找生成的llh.db文件。

默认的目录在data/data/项目包名/databases/..