Programming Ecto

Running Transactions with Functions

The first way to run Repo.transaction is by passing in a function containing the operations you’d like to run within the transaction. This can be an anonymous function or a named function defined elsewhere. This seems like a good idea—we’re functional programmers, and this approach will let us keep using functions. Let’s try it out.

To illustrate how this works, we’re going to introduce a new database table, and a module to go with it. Imagine that we’ve decided that we want to keep a log of the changes we make to our database. Every time we make a change, we’ll insert a new record into a logs table. We’ll use functions in the MusicDB.Log module to create changesets for logging the different operations that ...