Quel

1. We will not cover this section, aside from making a few remarks about this language.
   • Quel was the original query language for the Ingres dbms. Ingres is now available with SQL.
   • Quel closely resembles the tuple relational calculus.

   • Queries use the range of, retrieve and where clauses.

   • A typical query:

     
                  range of t is borrow
     
                  range of s is deposit
     
     	     retrieve unique (s.cname)
     
     	     where t.bname=``SFU'' and
     
     		          s.bname=``SFU'' and
     
     		 	  t.cname=s.cname
     
     

     This finds the names of all customers who have both a loan and an account at the SFU branch.

   • There is no representation for or in Quel.
   • Quel has the power of the relational algebra by means of the any aggregate function and the use of insertion and deletion into temporary relations.

• Converting Queries Easily Into Any Language