How to ensure default value is kept?

Posted on 2004-05-03
Last Modified: 2012-08-13

I have a table which includes links e.g., however I wish to make sure that these links always have the value of http:// at the front and if they dont, to come up with an error message telling the user to enter http:// at the front of the link. I know this can be done using validation rules but I am not entirely sure what coding to use as all I have tried has failed. Thanks in advance,

Question by:Danives
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Expert Comment

ID: 10976520
not sure which db you are using?

M$ Access you could have a validation rule and for Sql server or any others
you could have a trigger on update or insert.

Author Comment

ID: 10976557
Sorry forgot 2 mention it, Im using M$ Access, hoping to use the validation rule to fix my problem. Thanx

Assisted Solution

danths earned 250 total points
ID: 10976578
oops clicked submit too fast..
pseudo code:-

if (lcase$(left(myColumn, 7)) = "http://") then
   Raise Error "Not a valid url"
end if

and where RE 's are supported
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Author Comment

ID: 10976640
Im sorry I am not very proficent in using coding in MS Access, does this go into the validation field or do I have to enter this into visual basic through Access?
LVL 65

Expert Comment

ID: 10977290
on the beforeupdate event of the textbox (assuming thats what they use to enter the hyperlink) or whatever else control

private sub xxx_BeforeUpdate(Cancel as Integer)

    if left$(xxxx.Value, 7) <> "http://" then
       msgbox "URL must begin with http://"
       Cancel = True
     end if
end sub

basically check first 7 characters of the control called xxxx, if it does not equal http:// then throw error, set cancel to true so that user remains on that field


Accepted Solution

Younkman earned 250 total points
ID: 10977315
Danths code is VB, if you want to use the table wizard and vaildation rules, heres how you would write it: (this is simply a mod of his code)

Validation Rule: LCase$(Left([mycolumn],7))="http://"
Validation Text: Please use http:// at the beginning of the URL

Where mycolumn is the name of the column you want the validation rule to apply to.

LVL 65

Expert Comment

ID: 10977316
sorry, forgot to add
danths has used the left command, that is the best method to use when checking for starting characters

danths has also converted the user entered value into lowercase, which helps

you could of course not throw an error and automatically place a http:// in front

private sub xxx_BeforeUpdate(Cancel as Integer)
    if left$(xxxx.Value, 7) <> "http://" then xxxx.value = "http://" & xxxx.Value
end sub

also, does this just use http://, can you enter ftp://, file:// etc


Author Comment

ID: 10977440
Thanks for all your help guys, its working!!!

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