Bank transfer examples of transaction operation methods in Android database

package ;
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public class MainActivity extends Activity {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  (savedInstanceState);
  setContentView(.activity_main);
 }
 //Click the button to execute this method public void transtation(View v){
  //1. Create an object of help class  BankOpenHelper bankOpenHelper = new BankOpenHelper(this);
  //2. Call the getReadableDatabase of the database help class object to create the database, initialize the table data, and get a SqliteDatabase object to transfer (sql statement)  SQLiteDatabase db = ();
  //3. Transfer money, reduce Li Si's money by 200, and Zhang San adds 200.  ();//Open a database transaction  try {
   ("update account set money= money-200 where name=?",new String[]{"Li Si"});
   int i = 100/0;//Simulate an exception   ("update account set money= money+200 where name=?",new String[]{"Zhang San"});
   ();//All SQL statements in the mark transaction are executed successfully  } finally {
   ();//Judge whether the transaction's tag is successful. If it is not successful, roll back the SQL statement executed before the error  }
 }
}

package ;
import ;
import ;
import ;
import ;
public class BankOpenHelper extends SQLiteOpenHelper {
 public BankOpenHelper(Context context) {
  super(context, "", null, 1);
  // TODO Auto-generated constructor stub
 }
 @Override
 public void onCreate(SQLiteDatabase db) {
  ("create table account (_id integer primary key autoincrement,name varchar(20),money varchar(20))");
  ("insert into account ('name','money') values ('Zhang San','2000')");
  ("insert into account ('name','money') values ('Li Si','5000')");
 }
 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  // TODO Auto-generated method stub
 }
}

<?xml version="1.0"?>
-<RelativeLayout tools:context=".MainActivity" android:paddingTop="@dimen/activity_vertical_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingBottom="@dimen/activity_vertical_margin" android:layout_height="match_parent" android:layout_width="match_parent" xmlns:tools="/tools" xmlns:andro>
<Button android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="@string/transtation" android:onClick="transtation" android:layout_centerInParent="true"/>
</RelativeLayout>

//Click the button to execute this methodpublic void transtation(View v){
 //1. Create an object of help class BankOpenHelper bankOpenHelper = new BankOpenHelper(this);
 //2. Call the getReadableDatabase of the database help class object to create the database, initialize the table data, and get a SqliteDatabase object to transfer (sql statement) SQLiteDatabase db = ();
 //3. Transfer money, reduce Li Si's money by 200, and Zhang San adds 200. ();//Open a database transaction try {
  ("update account set money= money-200 where name=?",new String[]{"Li Si"});
  int i = 100/0;//Simulate an exception  ("update account set money= money+200 where name=?",new String[]{"Zhang San"});
  ();//All SQL statements in the mark transaction are executed successfully } finally {
  ();//Judge whether the transaction's tag is successful. If it is not successful, roll back the SQL statement executed before the error }
}