示例代码
import pymysql class DataMigrate: def __init__(self, env): self.num = 50 self.ENV = env # From self.db_from = self.connect_jingyi(1) self.cursor_from = self.db_from.cursor() self.from_sql = ‘select first_project, status from product ‘ # To self.db_to = self.connect_jingyi() self.cursor_to = self.db_to.cursor() self.to_sql = "insert into product_copy(first_project, status) value(%s,%s)" def connect_jingyi(self, is_jingyi=0): if is_jingyi: if self.ENV == ‘test‘: return pymysql.connect(host=‘****‘, port=3306, user=‘***‘, passwd=‘***‘, db=‘from_db‘, charset=‘utf8‘ ) else: return pymysql.connect(host=‘****‘, port=3306, user=‘***‘, passwd=‘***‘, db=‘from_db‘, charset=‘utf8‘ ) else: if self.ENV == ‘test‘: return pymysql.connect(host=‘****‘, port=3306, user=‘***‘, passwd=‘***‘, db=‘to_db‘, charset=‘utf8‘ ) elif self.ENV == ‘pre‘: return pymysql.connect(host=‘*****‘, port=3306, user=‘***‘, passwd=‘***‘, db=‘to_db‘, charset=‘utf8‘ ) def migrate_date(self): len_from = self.cursor_from.execute(self.from_sql) for i in range(int(len_from / self.num)): print(i) data1 = self.cursor_from.fetchmany(self.num) self.cursor_to.executemany(self.to_sql, data1) data2 = self.cursor_from.fetchall() self.cursor_to.executemany(self.to_sql, data2) self.db_to.commit() self.db_from.close() self.db_to.close() if __name__ == ‘__main__‘: data_migrate = DataMigrate(‘self-test‘) data_migrate.migrate_date()
函数解析
fetchone() 获取游标下一条数据(元组)
fetchmany() 获取多条数据(元组列表)
fetchall() 获取所有数据(元组列表)
看下源码
... def fetchone(self): """Fetch the next row""" self._check_executed() if self._rows is None or self.rownumber >= len(self._rows): return None result = self._rows[self.rownumber] self.rownumber += 1 return result def fetchmany(self, size=None): """Fetch several rows""" self._check_executed() if self._rows is None: return () end = self.rownumber + (size or self.arraysize) result = self._rows[self.rownumber:end] self.rownumber = min(end, len(self._rows)) return result def fetchall(self): """Fetch all the rows""" self._check_executed() if self._rows is None: return () if self.rownumber: result = self._rows[self.rownumber:] else: result = self._rows self.rownumber = len(self._rows) return result ...