I've an application that both creates and maintains the database. Running this on MariaDB is generating an error. I can replicate this same error within the WebOrder sample application, by simply adding the following once I've migrated the database to MariaDB:

Code:
Object oSessionManager is a cWebSessionManagerStandard
    
    Function CreateSession String sRemoteAddress Returns String
        String  sRet
        Integer iLength iField
        Handle  hFile
        
        Move WebAppServerProps.File_Number      to hFile
        Move (RefTable(WebAppServerProps.Data)) to iField
        
        Get_Attribute DF_FIELD_LENGTH of hFile iField to iLength
        Decrement iLength
        
        Structure_Start hFile "ODBC_DRV"
            Set_Attribute DF_FIELD_LENGTH of hFile iField to iLength 
        Structure_End hFile DF_STRUCTEND_OPT_NONE
        
        Forward Get CreateSession sRemoteAddress to sRet
        Function_Return sRet
    End_Function
End_Object
The code was added to the oSessionManager object simply for this example (this isn't representative of real code!). And the point of decreasing the size of the field by just 1 is again just for this example, because I needed to change it.

The point is, that if you run this code, and try to adjust the size of the 'WebAppServerProps.Data' field, it generates the error:

C:\DataFlex\Examples\20.0\WebOrder\Programs\WebApp .exe
General error HY000 (4161)--[ma-3.1.13][10.6.4-MariaDB]Unknown data type: 'DEFAULT' Table = webappserverprops (265), Source = ODBC_DRV.Structure_End.CreateTable
DataFlex Error#: 12289 in line: 33379.