#1
  1. No Profile Picture
    Contributing User
    Devshed Newbie (0 - 499 posts)

    Join Date
    May 2000
    Posts
    36
    Rep Power
    15
    I know the answer is in a book somewhere but I have been reading so much my eyes are . What is the differance between null and not null, why or how should I use it.

    Thanks D. E. L.
  2. #2
  3. .Net Developer
    Devshed Novice (500 - 999 posts)

    Join Date
    Feb 2000
    Location
    London
    Posts
    987
    Rep Power
    15
    Hi,



    The NULL value means "no data".

    It is different from values such as 0 for numeric types or the empty string for string types.

    Of course, NOT NULL is just opposite to NULL definition.It should hold some data.


    ------------------
    SR -
    shiju.dreamcenter.net

    "The fear of the LORD is the beginning of knowledge..."

    [This message has been edited by Shiju Rajan (edited May 17, 2000).]
  4. #3
  5. No Profile Picture
    Junior Member
    Devshed Newbie (0 - 499 posts)

    Join Date
    May 2000
    Posts
    2
    Rep Power
    0
    Nullable fields should be used to keep track of data where it may or may not be available when the data is entered. If you choose not to have null fields, and the information for the field is not available when the data is loaded, you will need to have some sort of default that takes the place of the null.
    Not null is usually the preferred way of setting up fields, because it saves the overhead of the null indicator in both storage and search capabilities.

Similar Threads

  1. Design Problems- extra relationships
    By wordracr in forum Database Management
    Replies: 33
    Last Post: January 11th, 2004, 06:42 AM
  2. Need urgent help
    By nsiindia in forum MySQL Help
    Replies: 2
    Last Post: November 28th, 2003, 12:15 PM
  3. IF Statements, I don't get them.
    By IwanaLearn in forum PHP Development
    Replies: 8
    Last Post: December 6th, 2002, 09:04 AM
  4. php with statement to mysql, rookie in over his head
    By jim.hodgson in forum PHP Development
    Replies: 3
    Last Post: August 6th, 2001, 12:08 PM
  5. Uknow Known MYSQLERROR
    By andyw in forum MySQL Help
    Replies: 7
    Last Post: January 23rd, 2001, 09:34 AM

IMN logo majestic logo threadwatch logo seochat tools logo