Special Transaction Behaviour

The TransactionScope Property controls the timing of when a transaction opens.

BUT it actually has two different behaviours controlled by the ConditionalTransaction in the UserSettings class.

ConditionalTransaction

Controls if a transaction will be opened according to the TransactionScope property, or if there are additional requirements.

In ther ini file, this settings is determined by the poorly named ISAMTransaction flag.

When ISAMTransaction = Y then ConditionalTransaction is set to false and when ISAMTransaction = N then ConditionalTransaction is set to true.

Unfortunately in most magic applications, this setting is set to N causing a subtle behavior that requires explanation.

ConditionalTransaction = true (ISAMTransaction = N)

When a controller starts is about to start a transaction according to the TransactionScope setting - it'll first check the call stack for an Entity that comes from an SQL data source. Only if it finds an Entity that comes from an SQL data source - it'll open a transaction, otherwise it'll ignore the TransactionScope property - for example if the Entity is from an XML or Memory or Btrieve source.

Unfortunately this behavior was the default in magic for most applications and as such is the default behaviour for most migrated applications.

When we say "an Entity that comes from an SQL data source" this actually depends on the SupportsTransactions property of the Entity's DataProvider

ConditionalTransaction = false (ISAMTransaction = Y)

A transaction will be started according to the TransactionScope property.

---

Help us improve, Edit this page on GitHub
or email us at info@fireflymigration.com