next.jdbc.transaction — com.github.seancorfield/next.jdbc 1.3.909

Implementation of SQL transaction logic.

In general, you cannot nest transactions. clojure.java.jdbc would ignore any attempt to create a nested transaction, even tho' some databases do support it. next.jdbc allows you to call with-transaction even while you are inside an active transaction, but the behavior may vary across databases and the commit or rollback boundaries may not be what you expect. In order to avoid two transactions constructed on the same connection from interfering with each other, next.jdbc locks on the Connection object (this prevents concurrent transactions on separate threads from interfering but will cause deadlock on a single thread -- so beware).

Consequently, this namespace exposes a dynamic variable, *nested-tx*, which can be used to vary the behavior when an attempt is made to start a transaction when you are already inside a transaction.

*nested-tx* clj

Controls the behavior when a nested transaction is attempted.

Possible values are:

• :allow -- the default: assumes you know what you are doing!
• :ignore -- the same behavior as clojure.java.jdbc: the nested transaction is simply ignored and any SQL operations inside it are executed in the context of the outer transaction.
• :prohibit -- any attempt to create a nested transaction will throw an exception: this is the safest but most restrictive approach so that you can make sure you don't accidentally have any attempts to create nested transactions (since that might be a bug in your code).