Ok saiharitha,

For that you need to define many2many field instead of One2many there,

after that you can select multiple subjects

See this video this will help you to do this: https://goo.gl/wg6NaL

Accept and Upvote answer if helpful

Thanks and regards

Haresh Kansara

ok haresh ,i have a tree view (one2many fields) i want to put it checkbox for eg: i have a students subjects list in tree view . the student has select one or more subjects from the tree view so i will put checkbox what i will do