SQLAlchemy并处理大量结果

本文介绍了SQLAlchemy并处理大量结果的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我需要从一个大表的所有行中读取数据，但是我不想一次将所有数据都拉到内存中.是否有一个可以处理分页的SQLAlchemy函数?也就是说，将几行存储到内存中，然后在需要时获取更多行.

I need to read data from all of the rows of a large table, but I don't want to pull all of the data into memory at one time. Is there a SQLAlchemy function that will handle paging? That is, pull several rows into memory and then fetch more when necessary.

我了解您可以使用limit和offset作为本文建议，但如果不需要的话，我宁愿不处理.

I understand you can do this with limit and offset as this article suggests, but I'd rather not handle that if I don't have to.

推荐答案

如果您使用的是Flask-SqlAlchemy，请参见query的api/#flask_sqlalchemy.BaseQuery.paginate"rel =" noreferrer> paginate 方法. paginate提供了几种简化分页的方法.

If you are using Flask-SqlAlchemy, see the paginate method of query. paginate offers several method to simplify pagination.

record_query = Record.query.paginate(page, per_page, False) total = record_query.total record_items = record_query.items

首页应为1，否则.total返回异常除以零

First page should be 1 otherwise the .total returns exception divided by zero