I am using the Peewee module as the ORM for my project.
I read the entire documentation, there is no clear example on how to process the result from db.execute_sql().
I traced the code, only can find db.execute_sql() return back the cursor.
Does anyone knows how to process the cursor, such as iterate over it and get back the result from complex select statement.
Update: I just found the following source code from peewee folder, it should help me to resolve this problem.
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
Peewee is a Python ORM (Object-Relational Mapping) library which supports SQLite, MySQL, PostgreSQL and Cockroach databases. This tutorial will help you to understand how to insert a new record, delete a record, create an index, etc., with the help of Peewee.
Peewee is a simple and small ORM. It has few (but expressive) concepts, making it easy to learn and intuitive to use. a small, expressive ORM. python 2.7+ and 3.4+ (developed with 3.6) supports sqlite, mysql, postgresql and cockroachdb.
Peewee returns a cursor. Then you can use the db-api 2 to iterate over it:
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
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