package com.example.databasetest;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;
public class MyDatabaseHelper extends SQLiteOpenHelper{
public static final String CREATE_BOOK = "create table Book (" + "id integer primary key autoincrement," + "author text," + "price real,"+ "pages integer," + "name text)";
public static final String CREATE_CATEGORY = "create table Category(" + "id integer primary key autoincrement" + "category_name text" + "category_code integer";
private Context mContext;
public MyDatabaseHelper(Context context,String name,CursorFactory factory,int version) {
super(context,name,factory,version);
mContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_BOOK);
db.execSQL(CREATE_CATEGORY);
Toast.makeText(mContext ,"Create succeeded",Toast.LENGTH_LONG).show();
}
@Override
public void onUpgrade(SQLiteDatabase db,int oldVersion ,int newVersion) {
db.execSQL("drop table if exists Book");
db.execSQL("drop table if exists Category");
onCreate(db);
}
}
dbHelper = new MyDatabaseHelper(this,"BookStore.db",null,2);
getReadableDatabase()
和·getWritableDatabase()`方法是可以创建和升级数据库的,这两个方法还会返回一个SQLiteDatabase对象。联系客服