android SQlite数据库

//   通过SQLiteOpenHelper调用如下方法时会返回SQLiteDatabase，通过SQLiteDatabase可以对数据库进行操作
getWritableDatabase()
getReadableDatabase()

public class PersonService {
    private DBOpenHelper dbOpenHelper;

    public PersonService(Context context) {
        this.dbOpenHelper = new DBOpenHelper(context);
    }
    
    public void payment(){     通过SQLiteOpenHelper调用如下方法时会返回SQLiteDatabase，通过SQLiteDatabase可以对数据库进行操作
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        db.beginTransaction();//开启事务
        try{
            db.execSQL("update person set amount=amount-10 where personid=1");
            db.execSQL("update person set amount=amount+10 where personid=2");
            db.setTransactionSuccessful();//设置事务的标志为True
        }finally{
            db.endTransaction();//结束事务,有两种情况：commit,rollback,
        //事务的提交或回滚是由事务的标志决定的,如果事务的标志为True，事务就会提交，否侧回滚,默认情况下事务的标志为False
        }
    }
    /**
     * 添加记录
     * @param person
     */
    public void save(Person person){
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        db.execSQL("insert into person(name, phone, amount) values(?,?,?)",
                new Object[]{person.getName(), person.getPhone(), person.getAmount()});
    }
    /**
     * 删除记录
     * @param id 记录ID
     */
    public void delete(Integer id){
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        db.execSQL("delete from person where personid=?", new Object[]{id});
    }
    /**
     * 更新记录
     * @param person
     */
    public void update(Person person){
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        db.execSQL("update person set name=?,phone=?,amount=? where personid=?",
                new Object[]{person.getName(), person.getPhone(),  person.getAmount(), person.getId()});
    }
    /**
     * 查询记录
     * @param id 记录ID
     * @return
     */
    public Person find(Integer id){
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.rawQuery("select * from person where personid=?", new String[]{id.toString()});
        if(cursor.moveToFirst()){
            int personid = cursor.getInt(cursor.getColumnIndex("personid"));
            int amount = cursor.getInt(cursor.getColumnIndex("amount"));
            String name = cursor.getString(cursor.getColumnIndex("name"));
            String phone = cursor.getString(cursor.getColumnIndex("phone"));
            return new Person(personid, name, phone, amount);
        }
        cursor.close();
        return null;
    }
    /**
     * 分页获取记录
     * @param offset 跳过前面多少条记录
     * @param maxResult 每页获取多少条记录
     * @return
     */
    public List<Person> getScrollData(int offset, int maxResult){
        List<Person> persons = new ArrayList<Person>();
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.rawQuery("select * from person order by personid asc limit ?,?",
                new String[]{String.valueOf(offset), String.valueOf(maxResult)});
        while(cursor.moveToNext()){
            int personid = cursor.getInt(cursor.getColumnIndex("personid"));
            int amount = cursor.getInt(cursor.getColumnIndex("amount"));
            String name = cursor.getString(cursor.getColumnIndex("name"));
            String phone = cursor.getString(cursor.getColumnIndex("phone"));
            persons.add(new Person(personid, name, phone, amount));
        }
        cursor.close();
        return persons;
    }
    /**
     * 分页获取记录
     * @param offset 跳过前面多少条记录
     * @param maxResult 每页获取多少条记录
     * @return
     */
    public Cursor getCursorScrollData(int offset, int maxResult){
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.rawQuery("select personid as _id,name,phone,amount from person order by personid asc limit ?,?",
                new String[]{String.valueOf(offset), String.valueOf(maxResult)});
        return cursor;
    }
    
    /**
     * 获取记录总数
     * @return
     */
    public long getCount(){
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.rawQuery("select count(*) from person", null);
        cursor.moveToFirst();
        long result = cursor.getLong(0);
        cursor.close();
        return result;
    }
}

public class OtherPersonService {
    private DBOpenHelper dbOpenHelper;

    public OtherPersonService(Context context) {
        this.dbOpenHelper = new DBOpenHelper(context);
    }
    /**
     * 添加记录
     * @param person
     */
    public void save(Person person){
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put("name", person.getName());
        values.put("phone", person.getPhone());
        values.put("amount", person.getAmount());
        db.insert("person", null, values);
    }
    /**
     * 删除记录
     * @param id 记录ID
     */
    public void delete(Integer id){
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        db.delete("person", "personid=?", new String[]{id.toString()});
    }
    /**
     * 更新记录
     * @param person
     */
    public void update(Person person){
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put("name", person.getName());
        values.put("phone", person.getPhone());
        values.put("amount", person.getAmount());
        db.update("person", values, "personid=?", new String[]{person.getId().toString()});
    }
    /**
     * 查询记录
     * @param id 记录ID
     * @return
     */
    public Person find(Integer id){
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.query("person", null, "personid=?", new String[]{id.toString()}, null, null, null);
        
        if(cursor.moveToFirst()){
            int personid = cursor.getInt(cursor.getColumnIndex("personid"));
            int amount = cursor.getInt(cursor.getColumnIndex("amount"));
            String name = cursor.getString(cursor.getColumnIndex("name"));
            String phone = cursor.getString(cursor.getColumnIndex("phone"));
            return new Person(personid, name, phone, amount);
        }
        cursor.close();
        return null;
    }
    /**
     * 分页获取记录
     * @param offset 跳过前面多少条记录
     * @param maxResult 每页获取多少条记录
     * @return
     */
    public List<Person> getScrollData(int offset, int maxResult){
        List<Person> persons = new ArrayList<Person>();
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.query("person", null, null, null, null, null, "personid asc", offset+ ","+ maxResult);
        
        while(cursor.moveToNext()){
            int personid = cursor.getInt(cursor.getColumnIndex("personid"));
            int amount = cursor.getInt(cursor.getColumnIndex("amount"));
            String name = cursor.getString(cursor.getColumnIndex("name"));
            String phone = cursor.getString(cursor.getColumnIndex("phone"));
            persons.add(new Person(personid, name, phone, amount));
        }
        cursor.close();
        return persons;
    }
    /**
     * 获取记录总数
     * @return
     */
    public long getCount(){
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.query("person", new String[]{"count(*)"}, null, null, null, null, null);
        cursor.moveToFirst();
        long result = cursor.getLong(0);
        cursor.close();
        return result;
    }
}