Working with WFS Tables that have Nested Structures - MapInfo_Pro - 2023

Web Feature Service (WFS) table definitions can contain nested structures. The following example shows a Parcel table that contains a column called Occupant.

Parcel Information Table
	Street_Address
	City
	State
	Zip_Code
	Occupant
		Person
			Name_First
			Name_Last
			Age

The Occupant column refers to a structure or table called Person. The Person structure contains columns called First_Name, Last_Name, and Age. Depending on how the schema of the table is defined, the column (Occupant) can occur multiple times per row (record). To address nested structures, the column names in WFS tables may use delimiters (such as Occupant/Person/Name_First), and may be lengthy.

MapInfo Pro has limitations on column names: it truncates column names that are longer than 32 characters, and it does not support the back-slash ( / ) character in column names (so it would not recognize Occupant/Person/Name_First as a valid column name). When MapInfo Pro encounters a WFS table with column names that conflict with these limitations, it uses the first and last names in the nested structure with a hash character (#) as a delimiter. As an example, MapInfo Pro creates the previous Parcel table with the following column names:

Street_Address
City
State
Zip_Code
Name_First#Occupant
Name_Last#Occupant
Age#Occupant

The hash character (#) in the column name indicates that it is a nested structure. If the data from the server contains more than one Occupant column per row, then MapInfo Pro brings in the last value it encounters.

MapInfo Pro ensures that all new column names are unique. If there are identical column names, then MapInfo Pro applies a numeric value as the last character of each of the identical column names (such as Age#Occupant1 and Age#Occupant2).

MapInfo Pro converts any unrecognized characters in a column name to an underscore ( _ ).

The nested structure schema is more common among WFS 2.0 and 1.1 servers than WFS 1.0 servers. MapInfo Pro processes the schema for all the three servers WFS 1.0, WFS 1.1 and WFS 2.0, but only populates WFS 2.0 and 1.1 columns.