Pass through / virtual field¶
Table of contents:
There are three columns config types that do similar things but still have subtle differences between them. These are the none type, the passthrough type and the user type.
A value sent to the
DataHandleris kept as is and put into the database field. However, the default TYPO3 backend forms never send data for a
Unlike the field type
none, the field type
passthroughmust have a database field.
The TYPO3 backend forms do not render anything for
passthroughfields by default. But they can be combined with a custom
renderTypeto display something. A field of type
useris better suited for such use cases, though.
passthroughfields are usually not rendered at other places in the backend.
Field updates by the
DataHandlerget logged and the history/undo function will work with such values.
passthrough field can be useful, if:
A field needs no rendering, but some data handling using hooks of the
The passthrough type is used by TYPO3 core to handle meta data on records rows that are not shown as fields if editing records and only have data logic attached to it. An example is the
l18n_diffsourcefield whose data is rendered differently in FormEngine at other places if editing a record but still updated and handled by the
Typical usages of the field type
passthrough is a field that only needs data evaluation on the
DataHandler side, but
no rendering definition. The
DataHandler does not evaluate the value in any way by default.
Since there is no rendering mode for this field type it is specifically fitted for direct API usage with the
This field is found in a number of tables, for instance the "pages" table. It is used by the system extension "impexp" to store some information.
'tx_impexp_origuid' => [ 'config' => [ 'type' => 'passthrough' ], ],