writing same data twice

jlsports

How do I prevent the same data from being put into the data-base more than once.

I developed a contest where users select baseball teams on a daily basis. So they would click on a link that says Los Angeles and their selection would then be put into the data base. Before writing to the data-base it checks to make sure thay they have not already made a selection for that day and for the most part everything works. But every once in a while the same data is writen twice. ANy ideas how to prevent this from happening.

Any help would be greatly appreciated

pete_bisby

You can always extend your primary key to include the date and baseball team.
This way, when you, or your program/query, attempts to enter a record into the table, the request will be rejected.

Or you can try and find out why it's going wrong - it might take a bit of time, but once you've found it and solved it, think of the satisfaction ... !

jlsports

Here is my data-base structure and that might help

date date NOT NULL default '0000-00-00',
time datetime NOT NULL default '0000-00-00 00:00:00',
id int(11) NOT NULL default '0',
team varchar(14) NOT NULL default '',
ipaddress varchar(20) NOT NULL default ''

So basicly the same ID can't have more than 1 selection for any given date.

Thanks

pete_bisby

But didn't you say that the same information was being put into the table more than once?

If you had the table definition, like the example below: ...

CREATE TABLE baseball (
  bbDate date NOT NULL default '0000-00-00',
  bbTime datetime NOT NULL default '0000-00-00 00:00:00',
  id int(11) NOT NULL default '0',
  team varchar(14) NOT NULL default '',
  ipaddress varchar(20) NOT NULL default '',
  PRIMARY KEY  (id,date,team)
)

... it would cure the problem. Please note the Primary Key - you table structure didn't have one, or the id field was the only field in your Primary Key.

Also note that I've changed the field names slightly on date and time - these are both keywords within SQL, and may cause you problems later on.

jlsports

Thanks for all your help. I will try your suggestions and see what happens. I can't begin to tell you how much of a resource I have found this site to be. Thanks again