007_01SQLiteTransaction

 1 package com.example.sqlitetransaction;
 2
 3 import android.content.Context;
 4 import android.database.sqlite.SQLiteDatabase;
 5 import android.database.sqlite.SQLiteDatabase.CursorFactory;
 6 import android.database.sqlite.SQLiteOpenHelper;
 7 import android.util.Log;
 8
 9 public class MydbOpenHelper extends SQLiteOpenHelper {
10
11     //
12     public MydbOpenHelper(Context context, String name, CursorFactory factory,
13             int version) {
14         super(context, name, factory, version);
15         // TODO Auto-generated constructor stub
16     }
17
18
19     //oncreate函数当数据库第一次被创建的时候会调用
20     @Override
21     public void onCreate(SQLiteDatabase db) {
22         // TODO Auto-generated method stub
23         String createtable = "create table user(id int, name varchar(20), money int);";
24         db.execSQL(createtable);
25         System.out.println("MydbOpenHelper.onCreate()");
26     }
27
28
29     //onUpgrade当你的数据库版本升级的时候会调用
30     @Override
31     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
32         // TODO Auto-generated method stub
33         //更改数据库的表结构
34         //  user(id,name,password)  user(id,name,password,gender)
35         //
36         //  db.execSQL("");
37         Log.i("MydbOpenHelper", "oldervserion"+oldVersion+"newversion"+newVersion);
38         System.out.println("MydbOpenHelper.onUpgrade()");
39
40     }
41
42 }

MydbOpenHelper.java

 1 package com.example.sqlitetransaction;
 2
 3 import android.app.Activity;
 4 import android.content.ContentValues;
 5 import android.database.Cursor;
 6 import android.database.sqlite.SQLiteDatabase;
 7 import android.os.Bundle;
 8 import android.util.Log;
 9 import android.view.Menu;
10 import android.view.MenuItem;
11
12 public class MainActivity extends Activity {
13     SQLiteDatabase db;
14
15     @Override
16     protected void onCreate(Bundle savedInstanceState) {
17         super.onCreate(savedInstanceState);
18         setContentView(R.layout.activity_main);
19
20         MydbOpenHelper helper = new MydbOpenHelper(this, "count.db", null,1);
21         db = helper.getReadableDatabase();
22
23         //insert();
24         try {
25             update();
26             query();
27         }
28         finally{
29             db.close();
30         }
31
32         }
33     private void update(){
34         db.beginTransaction();
35         try{
36             ContentValues cv = new ContentValues();
37             cv.put("money", 7000);
38             db.update("user", cv, "id=1", null);
39
40             //int b = 1/0;
41
42             cv.clear();
43             cv.put("money", 11000);
44             db.update("user", cv, "id=2", null);
45             db.setTransactionSuccessful();
46         }catch(Exception e){
47
48         }finally{
49             db.endTransaction();
50         }
51
52     }
53     private void query(){
54         Cursor c = db.rawQuery("select * from user", null);
55
56         while(c.moveToNext()){
57             int id = c.getInt(c.getColumnIndex("id"));
58             String username = c.getString(c.getColumnIndex("name"));
59             String money = c.getString(c.getColumnIndex("money"));
60             Log.i("sqlitetransaction", id+","+username+","+money);
61         }
62     }
63     private void insert(){
64         ContentValues cv = new ContentValues();
65         cv.put("id", 1);
66         cv.put("name", "user1");
67         cv.put("money", 8000);
68         db.insert("user", null, cv);
69         cv.clear();
70
71         cv.put("id", 2);
72         cv.put("name", "user2");
73         cv.put("money", 10000);
74         db.insert("user", null, cv);
75         cv.clear();
76     }
77 }

MainActivity.java