To start inserting data from an external source into your TYPO3 CMS tables, you must first extend their TCA with a specific syntax. This syntax is comprised of 3 parts:
general information ("General TCA configuration")
specific information for each column where data will be stored ("Columns configuration")
so-called "additional fields" which are read from the external source, but not saved
The first two parts are required, the third is optional.
This chapter describes all possible configuration options. For each property, a step or a more general scope is mentioned to help understand which part of the process it impacts. The names of the steps correspond to the process steps.
There are some code examples throughout this chapter. They are taken either from the External Import Tutorial or from the test extension: https://github.com/fsuter/externalimport_test. You are encouraged to refer to them for more examples and more details about each example (in the Tutorial).