yesodweb / yesodweb/persistent

updateBy

Open
#853 4 comments 5 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

enhancement
Dominant language
Haskell
Stars
486
Forks
306
PR merge metrics
No merged PRs in 30d

Description

Would Persistent users be interested in having an updateBy function? This is what we have in our internal codebase:

updateBy :: (MonadIO m, PersistUniqueRead backend, PersistEntity record, PersistStoreWrite backend, PersistEntityBackend record ~ BaseBackend backend) 
         => Unique record 
         -> [Update record] 
         -> ReaderT backend m ()
updateBy unique updates = do
  mExisting <- getBy unique
  case mExisting of 
    Just (Entity key _) -> update key updates
    Nothing -> return ()

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by locating the existing getBy and update definitions in Persistent's API. Use the supplied implementation as the behavioral reference, including doing nothing when the unique key has no matching entity. Done means Persistent exposes updateBy with the requested signature and behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
haskell
Domain
database
Issue type
Feature
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.