INDEX-EXISTS- — Tests for the existence of a database index.
Function
nameThe name of the index as a string, symbol or SQL expression.
owner
              A string, NIL or :all. 
            
databaseA database object which defaults to *default-database*.
resultA Boolean.
Tests for the existence of an SQL index called
      name in database
      which defaults to
      *default-database*. owner
      is NIL by default which means that only indexes owned by users
      are examined. If owner is a string
      denoting a user name, only indexes owned by
      owner are examined. If
      owner is :all then all
      indexes are examined.