Concepts¶

Things hopefully are straightforward but it’s important to get the following straight in your head; the rest will come easier if you do.

Source vs. Target¶

Data always flows from source to target, it is the #1 rule.

Docs and command output will always reflect this, e.g. CSV → Wutta.

Source and target can be anything as long as the import handler and importer(s) implement the desired logic. The app database is often involved but not always.

Import vs. Export¶

Surprise, there is no difference. After all from target’s perspective everything is really an import.

Sometimes it’s more helpful to think of it as an export, e.g. Wutta → CSV really seems like an export. In such cases the orientation may be set to reflect the distinction.

Import Handler vs. Importer¶

The import handler is sort of the “wrapper” around one or more importers and the latter contain the table-specific sync logic.

In a DB or similar context, the import handler will make the connection, then invoke all requested importers, then commit transaction at the end (or rollback if dry-run).

And each importer will read data from source, and usually also read data from target, then compare data sets and finally write data to target as needed. But each would usually do this for just one table.