The differences between .build, .create, and .create! and when should they be used?

Question

So I've been seeing people using .build, .create, and .create! within their controllers more and more lately. What's the difference from just using .new and passig the param'd object and then .save? Are there pros and cons? Does using these other methods offer benefits?

Answer 1

#create is shorter version of new and save. #create! is throwing exception if validation was not positive.

Answer 2

There are a couple differences, but they're not big:

1. .create is equivalent to .new followed by .save. It's just more succinct.
2. .create! is equivalent to .new followed by .save! (throws an error if saving fails). It's also just a wee bit shorter
3. I think .build is an alias for .new.

The most important part, however, is that these methods can be called through an association (has_many, etc.) to automatically link the two models.