• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Part VII: Appendixes > The Quotient: An Additional Operation of the Relational ...

Appendix B. The Quotient: An Additional Operation of the Relational Algebra

The quotient of two tables is not used often, but has a very specific use. It arises when we wish to select those rows of a table that are sufficient to provide all possible values in certain columns. As an example, imagine a business that makes furniture. The database for this business has a table on the types of wood that they use and on suppliers of wood and which types they supply. Examples are shown in Table 2.1 and Table 2.2 (of course, these tables would include more columns, but this is just to illustrate the point):

Table B.1. WOOD
Type
Mahogany
Red oak
Poplar
Walnut



PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint