Android sqlite 数据库在java代码中的增删改查

 private void queryPerson(PersonSQLiteOpenHelper personSQLiteOpenHelper) {
        SQLiteDatabase sqLiteDatabase = personSQLiteOpenHelper.getReadableDatabase();
        Cursor cursor = sqLiteDatabase.query("person", new String[]{"id", "name", "age"}, null, null, null, null, null, null);
        while(cursor.moveToNext()) {
            int id = cursor.getInt(cursor.getColumnIndex("id"));
            String name = cursor.getString(cursor.getColumnIndex("name"));
            int age = cursor.getInt(cursor.getColumnIndex("age"));
            System.out.println("id = " + id);
            System.out.println("name = " + name);
            System.out.println("age = " + age);
            System.out.println("————————————————————————————————");
        }
    }

    private void deletePerson(PersonSQLiteOpenHelper personSQLiteOpenHelper) {
        SQLiteDatabase sqLiteDatabase = personSQLiteOpenHelper.getWritableDatabase();
        sqLiteDatabase.delete("person", "id=?", new String[]{"2"});
        sqLiteDatabase.close();
    }

    /**
     * 模拟事务
     */
    private void transactionTest(){
        SQLiteDatabase sqLiteDatabase = SQLiteDatabase.openOrCreateDatabase("/data/data/com.wuyou.sqlitetest/databases/person.db",null);
        //首先打开一个事务
        sqLiteDatabase.beginTransaction();
        try {
            sqLiteDatabase.execSQL("update person set age = 44 where id=1");

            //模拟事务失败
            String x = null;
            x.equals("");

            sqLiteDatabase.execSQL("update person set age = 11 where id=4");
            //标记事务成功
            sqLiteDatabase.setTransactionSuccessful();
        }catch (Exception e){
            System.out.println("处理事务的时候出现异常 ");
        } finally {
            //最终标记事务完成
            sqLiteDatabase.endTransaction();
            sqLiteDatabase.close();
        }
    }
    /**
     * 添加一个人
     *
     * @param sqLiteOpenHelper
     */
    public void addPerson(SQLiteOpenHelper sqLiteOpenHelper) {
        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("name", "wuyou");
        contentValues.put("age", 21);
        database.insert("person", null, contentValues);
        database.close();
    }

    public void updatePerson(SQLiteOpenHelper sqLiteOpenHelper) {
        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("name", "zhangsan");
        contentValues.put("age", 33);
        database.update("person", contentValues, "id=?", new String[]{"1"});
        database.close();
    }