This diagram is explained in the text. It shows the main ways you can generate XML using Oracle XML DB. It shows in block diagram format, one block listing the SQLX functions, another block listing the SQL functions. A third block showing DBMS_XMLGEN. These three blocks are in the database and all point to XMLType columns or tables. A block outside the database shows the two XDK options for generating XML, namely, XSQL Pages Publishing Framework and XSU.