In the meantime, you can just use a RawUtf8 property.
For MySQL and FireDAC it won't make any difference.
]]>ExceptionMessage="[FireDAC][Phys][MySQL]-335. Parameter [LA] data type is unknown. Hint: specify TFDParam.DataType or assign TFDParam value before Prepare/Execute call"
Investigating mormot.db.rad, line 586
DatasetBindSqlParam(arrndx, p, fParams[p]);
I noticed that the VType for this RawJson Field in fParams is ftNull. changing during debugging to ftutf8 it saves the TOrm object in the database without error
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