+
+ if erFile:
+ s += """
+.sp 1
+.SH "TABLE RELATIONSHIPS"
+.PP
+The following diagram shows the relationship among tables in the
+database. Each node represents a table. Tables that are part of the
+``root set'' are shown with double borders. Each edge leads from the
+table that contains it and points to the table that its value
+represents. Edges are labeled with their column names. Thick lines
+represent strong references; thin lines represent weak references.
+.RS -1in
+"""
+ erStream = open(erFile, "r")
+ for line in erStream:
+ s += line + '\n'
+ erStream.close()
+ s += ".RE\n"
+