Any cataloged or browsed theme is built on the basis of some map, it is only a certain method of displaying data stored in the map. In this connection, it is impossible to set a link between some feature type and a table in the theme if there is no such a link in the corresponding map. A reverse situation is possible: some links of a map can be unnecessary for a particular theme and can be excluded from this theme.
The page “Links” of the property sheet of theme feature type does not differ in outward appearance from the analogous page for map feature type (figure 32-1) described above, but its does differ from it in its functional capabilities.
The button Change is present on the page but it is always disabled, because it is not possible to change the link mode for the theme compared to the one specified for the map.
When pushing the button Create, the system opens instead of the wizard of creating links a dialog box containing a list of only those GDB tables which are not linked with the present feature type of the theme, but are linked with the map feature type of the same name.
Pushing the button Remove breaks the link between theme feature type and selected table, however, the link between map feature type of the same name and this table is retained.
Chapter 43 “Links of maps with tables and queries of EDB” will examine links between feature types and tables of external databases. In this case, the link set for map feature type cannot be removed for theme feature type, unlike the link with internal tables of GDB described in this section.
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