/** * 銀行轉賬操作 */ public void transation(){ db.beginTransaction(); try { //name為微明的用戶向小紅轉賬 ContentValues contentValues=new ContentValues(); contentValues.put("money", 1000); db.update("person", contentValues, "name=?", new String[]{"微明"}); ContentValues contentValues2=new ContentValues(); contentValues2.put("money", 1100); db.update("person", contentValues2, "name=?", new String[]{"小紅"}); //全部語句運行完畢，若沒有異常，則會運行這句設置事務成功的標記 db.setTransactionSuccessful(); } finally { //會檢查事務的標識，若沒有調用setTransactionSuccessful()方法設置標志，則回滾事務。否則提交事務。 db.endTransaction(); } } } MyOpenHelper.java **SQLiteOpenHelper: * A helper class to manage database creation and version management. * 所以，SQLiteOpenHelper是對庫本身的操作。若要對庫中數據操作，須要使用庫對象的方法。 */ import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; public class MyOpenHelper extends SQLiteOpenHelper { //name:數據庫文件的名字 //factory：游標工廠 //version：版本號,必須大于等于1 public MyOpenHelper(Context context, String name, CursorFactory factory, int version) { super(context, name, factory, version); // TODO Auto-generated constructor stub } //數據庫創建時調用 @Override public void onCreate(SQLiteDatabase db) { //創建一個person表 db.execSQL("create table person(_id integer primary key autoincrement, name char(10), phone char(20))"); System.out.println("oncreate調用了"); } //數據庫升級時調用 @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub System.out.println("onupgrade調用了"); db.execSQL("alter table person add money char(20)"); } } |