java - 一句话解释一下，什么是数据库中的游标？

Question

网上看了很多数据库游标的知识，越看越疑惑。
1.能不能举个例子说明一下，什么是数据库的游标？尽量简短的语言，解释清楚。
2.为什么存储过程尽量不使用游标，大数据量的处理会特别耗性能呢？

Answer 1

A cursor can be understood as the subscript of an array, usually used for traversal.
You can take a look at this
http://blog.51yip.com/mysql/1...

Answer 2

A cursor is an abstract object expression of the data collection you select

Answer 3

I don’t know much about it
1 Most of them are used for stored procedures to implement loops
2 The performance is so slow that it will kill you. You can test this with 1 million data

Answer 4

I don’t know either, I’m looking for an answer

Answer 5

A cursor is a data buffer opened by the system for users to store the execution results of SQL statements.

Answer 6

I think it is particularly like the iterator in the Java collection framework. If you understand iterator, you should be able to understand cursor