dcsimg
Results 1 to 4 of 4

Thread: Query Containment

Hybrid View

  1. #1
    Join Date
    Apr 2019
    Posts
    2

    Query Containment

    Hi guys, I need your help, please.

    Is "Query Containment" the same as "Nested Query"? If not, could you give me an easy example of what "Query Containment" is?

    Thank you. Peter

  2. #2
    Join Date
    Feb 2014
    Location
    Riviera Beach, Maryland, USA
    Posts
    60

  3. #3
    Join Date
    Apr 2019
    Posts
    2
    Hi SpywareDr,
    this is a really great lecture, thank you. However, it is written in such a technical language, that I was really struggling to understand. Somehow at the end I still do not know the answer. The problem is that we were given a small task:
    "Show a practical example of query containment." And my colleagues started giving examples of nested queries and SELECT inside another SELECT. Now I have a feeling that these topics are not related and that my colleagues are wrong. Are they? Or maybe me?
    Tank you. Peter.

  4. #4
    Join Date
    Feb 2014
    Location
    Riviera Beach, Maryland, USA
    Posts
    60
    Encyclopedia of Database systems > Query Containment
    Definition

    One query is contained in another if, independent of the values of the “stored data” (that is, database), the set of answers to the first query on the database is a subset of the set of answers to the second query on the same database.

    A formal definition of containment is as follows: [...continues...]

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •