diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
new file mode 100644
index 0fcd9f8..c07f5a2
*** a/doc/src/sgml/ddl.sgml
--- b/doc/src/sgml/ddl.sgml
*************** CREATE TABLE products (
*** 546,552 ****
  
     <para>
      Adding a unique constraint will automatically create a unique btree
!     index on the column or group of columns used in the constraint.
     </para>
  
     <indexterm>
--- 546,554 ----
  
     <para>
      Adding a unique constraint will automatically create a unique btree
!     index on the column or group of columns used in the constraint. 
!     A uniqueness constraint on only some rows can be enforced by creating
!     a <link linkend="indexes-partial">partial index</link>.
     </para>
  
     <indexterm>