Python Peewee execute_sql()示例

Question

我正在使用Peewee模块作为我的项目的ORM。

我阅读了整个文档，没有关于如何处理来自db.execute_sql()的结果的明确示例。

我跟踪了代码，只能找到db.execute_sql()返回游标。

有人知道如何处理游标吗？比如遍历游标并从复杂的select语句中返回结果。

更新：我刚从peewee文件夹中找到以下源代码，它应该能帮助我解决这个问题。

class QueryResultWrapper(object):
    """
    Provides an iterator over the results of a raw Query, additionally doing
    two things:
    - converts rows from the database into python representations
    - ensures that multiple iterations do not result in multiple queries
    """
    def __init__(self, model, cursor, meta=None):
        self.model = model
        self.cursor = cursor

        self.__ct = 0
        self.__idx = 0

        self._result_cache = []
        self._populated = False
        self._initialized = False

        if meta is not None:
            self.column_meta, self.join_meta = meta
        else:
            self.column_meta = self.join_meta = None

    def __iter__(self):
        self.__idx = 0

        if not self._populated:
            return self
        else:
            return iter(self._result_cache)

    def process_row(self, row):
        return row

    def iterate(self):
        row = self.cursor.fetchone()
        if not row:
            self._populated = True
            raise StopIteration
        elif not self._initialized:
            self.initialize(self.cursor.description)
            self._initialized = True
        return self.process_row(row)

    def iterator(self):
        while True:
            yield self.iterate()

    def next(self):
        if self.__idx  self.__ct):
            try:
                self.next()
            except StopIteration:
                break

Answer 1

Peewee返回一个光标。然后可以使用DB-API2对其进行迭代：

cursor = db.execute_sql('select * from tweets;')
for row in cursor.fetchall():
    print(row)

cursor = db.execute_sql('select count(*) from tweets;')
res = cursor.fetchone()
print('Total: ', res[0])

docs:database.execute_sql