Shulou(Shulou.com)06/02 Report--

This article introduces how to do save newspaper detached entity passed to persist when @ ManyToMany CascadeType.ALL. The content is very detailed. Interested friends can use it for reference. I hope it will be helpful to you.

First, there are two entities, user, role, user-role intermediate table. The relationship is as follows: public class User {@ ManyToMany (cascade = CascadeType.ALL) @ JoinTable (name = "user_role", joinColumns = @ JoinColumn (name = "user_id"), inverseJoinColumns = @ JoinColumn (name = "role_id") private Set groups = new HashSet (); / / omit getter, setter} II. Save data User code as follows: User user = new User (); Group g = groupRepo.findById (8) / / Database query Set gruops = new HashSet (); gruops.add (g); user.setGroups (gruops); userRepo.save (user)

UserRepo.save (user); error detached entity passed to persist occurs when saving data.

Error reason: when saving user, I want to cascade save gruops. But gruop already has an id value. So report the wrong message.

Solution, put user.setGroups (gruops); after saving the user. As follows:

User user = new User (); userRepo.save (user); / / Save userGroup g = groupRepo.findById (8) first; / / Database query Set gruops = new HashSet (); gruops.add (g); user.setGroups (gruops); / / then set groupsuserRepo.save (user) / / finally update user about @ ManyToMany CascadeType.ALL what to do with save newspaper detached entity passed to persist to share here. I hope the above content can be helpful to everyone and learn more knowledge. If you think the article is good, you can share it for more people to see.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.