优雅的处理Android数据库升级的问题

 1 package com.example.databaseissuetest;
 2 
 3 import android.content.Context;
 4 import android.database.sqlite.SQLiteDatabase;
 5 import android.database.sqlite.SQLiteOpenHelper;
 6 import android.text.TextUtils;
 7 import android.util.Log;
 8 
 9 public class DatabaseHelper extends SQLiteOpenHelper {
10     public static final String DB_NAME = "jjtest";
11 
12     private static final String[] COL_SQLS = {
13         "create table jjtest (id integer primary key autoincrement, name text, age int)",
14         "alter table jjtest add class text",
15         "alter table jjtest add friends integer default 3",
16         };
17 
18     public DatabaseHelper(Context context) {
19         super(context, DB_NAME, null, COL_SQLS.length);
20         Log.e("David", "DatabaseHelper");
21     }
22 
23     @Override
24     public void onCreate(SQLiteDatabase db) {
25         Log.e("David", "onCreate");
26         onUpgrade(db, 0, COL_SQLS.length);
27     }
28 
29     @Override
30     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
31         Log.e("David", "onUpgrade oldVersion = " + oldVersion);
32         Log.e("David", "onUpgrade newVersion = " + newVersion);
33         for (int i = oldVersion; i < COL_SQLS.length; i++) {
34             String sql = COL_SQLS[i];
35             if (!TextUtils.isEmpty(sql)) {
36                 db.execSQL(sql);
37             }
38         }
39     }
40 }