Thread: PHP, HTML Forms & PostgreSQL
Hi all,
I'm doing some intranet pages using PHP & PostgreSQL. (Our corporate
database is 'of course' using PostgreSQL ;-). I like this interface and
have had great help in looking at PgAdmin, which I have been using from
time to time.
I have some problems with HTML forms and how they interface to PHP, and
I haven't been able to locate any description of this (neither in the HTML
manuals or in the PHP manuals). From testing and looking at PgAdmin, I
figured out how to name variables and assign values.
However, my specific problem is using checkboxes:
1) If a checkbox is unchecked, I'm not getting any values,
2) If a checkbox is checked, I'm getting the value 'on' where I need 't'
in the update sql statement.
Is there any way to make sure the variable (checkbox) will appear in the
php action when the value changes (or every time)? Is there a way to make
the form 'return' 't' in stead of 'on'?
I'm using
PHP 4.1.1
PostgreSQL 7.2.1
Apache 1.3.23
Please help,
Leif
On Mon, Apr 08, 2002 at 11:26:47AM +0200, Leif Jensen wrote: > > Hi all, > > I'm doing some intranet pages using PHP & PostgreSQL. (Our corporate > database is 'of course' using PostgreSQL ;-). I like this interface and > have had great help in looking at PgAdmin, which I have been using from > time to time. > > I have some problems with HTML forms and how they interface to PHP, and > I haven't been able to locate any description of this (neither in the HTML > manuals or in the PHP manuals). From testing and looking at PgAdmin, I > figured out how to name variables and assign values. Lookup the HTML specs, I think they say something about this. It is defined somewhere. > However, my specific problem is using checkboxes: > > 1) If a checkbox is unchecked, I'm not getting any values, > > 2) If a checkbox is checked, I'm getting the value 'on' where I need 't' > in the update sql statement. > > Is there any way to make sure the variable (checkbox) will appear in the > php action when the value changes (or every time)? Is there a way to make > the form 'return' 't' in stead of 'on'? Nope, HTML just works that way. It works like that on every browser i've seen. Remember, those values come from the browser, not anything you can control. Note that the value= part of the checkbox controls the value returned when ticked. Something like: if( $box != "t" ) $box = "f" all done. HTH, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > Ignorance continues to thrive when intelligent people choose to do > nothing. Speaking out against censorship and ignorance is the imperative > of all intelligent people.
Hi Martijn, Thx for your quick reply. On Mon, 8 Apr 2002, Martijn van Oosterhout wrote: > On Mon, Apr 08, 2002 at 11:26:47AM +0200, Leif Jensen wrote: > > > > Hi all, > > > > I'm doing some intranet pages using PHP & PostgreSQL. (Our corporate > > database is 'of course' using PostgreSQL ;-). I like this interface and > > have had great help in looking at PgAdmin, which I have been using from > > time to time. > > > > I have some problems with HTML forms and how they interface to PHP, and > > I haven't been able to locate any description of this (neither in the HTML > > manuals or in the PHP manuals). From testing and looking at PgAdmin, I > > figured out how to name variables and assign values. > > Lookup the HTML specs, I think they say something about this. It is defined > somewhere. I have looked in the HTML 4.0 recommendation, which talks about how form data is being handled, but it doesn't say anything about how PHP treats the result. > > > However, my specific problem is using checkboxes: > > > > 1) If a checkbox is unchecked, I'm not getting any values, > > > > 2) If a checkbox is checked, I'm getting the value 'on' where I need 't' > > in the update sql statement. > > > > Is there any way to make sure the variable (checkbox) will appear in the > > php action when the value changes (or every time)? Is there a way to make > > the form 'return' 't' in stead of 'on'? > > Nope, HTML just works that way. It works like that on every browser i've > seen. Remember, those values come from the browser, not anything you can > control. > > Note that the value= part of the checkbox controls the value returned when > ticked. > > Something like: > > if( $box != "t" ) > $box = "f" > > all done. That's a possibility if you on forehand know the name(s) of checkboxes in your form. I was trying to make a general sql construction of an update statement independent of what might be in the form. !? Greetings, Leif
On Mon, Apr 08, 2002 at 12:52:48PM +0200, Leif Jensen wrote: > I have looked in the HTML 4.0 recommendation, which talks about how > form data is being handled, but it doesn't say anything about how PHP > treats the result. Hmm, I'm not sure then, but this is the way I've always known it to work. > That's a possibility if you on forehand know the name(s) of checkboxes > in your form. I was trying to make a general sql construction of an update > statement independent of what might be in the form. !? Well, I don't know if you can get the variables in a hash, like in perl. Another thing that sometimes works is: <input type=hidden name=box value=f> <input type=checkbox name=box value=t> When the tickbox is ticked, the browser will return two values named "box", which *may* cancel out to give you your t/f combo. Note this is extremely system specific and not guarenteed and not recommended. But I have used it successfully on occasion. -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > Ignorance continues to thrive when intelligent people choose to do > nothing. Speaking out against censorship and ignorance is the imperative > of all intelligent people.
Hi again, On Mon, 8 Apr 2002, Martijn van Oosterhout wrote: > On Mon, Apr 08, 2002 at 12:52:48PM +0200, Leif Jensen wrote: > > I have looked in the HTML 4.0 recommendation, which talks about how > > form data is being handled, but it doesn't say anything about how PHP > > treats the result. > > Hmm, I'm not sure then, but this is the way I've always known it to work. > > > That's a possibility if you on forehand know the name(s) of checkboxes > > in your form. I was trying to make a general sql construction of an update > > statement independent of what might be in the form. !? > > Well, I don't know if you can get the variables in a hash, like in perl. I have noticed that all the 'successful controls' are listed in the _GET array or the _POST array ! But their type is unknown. From here I can scan and generate my sql update statement! > Another thing that sometimes works is: > > <input type=hidden name=box value=f> > <input type=checkbox name=box value=t> > > When the tickbox is ticked, the browser will return two values named "box", > which *may* cancel out to give you your t/f combo. > > Note this is extremely system specific and not guarenteed and not > recommended. But I have used it successfully on occasion. > This might be worth a try, but as you say non-standard. In the tests I have done, PHP (or maybe it's rather the user agent!?) puts the controls in corresponding variables in the order they are listed in the form. And what happens to the value when the user toggles the checkbox ? Thanks, Leif
On Mon, 8 Apr 2002, Martijn van Oosterhout wrote: > On Mon, Apr 08, 2002 at 12:52:48PM +0200, Leif Jensen wrote: > > I have looked in the HTML 4.0 recommendation, which talks about how > > form data is being handled, but it doesn't say anything about how PHP > > treats the result. > > Hmm, I'm not sure then, but this is the way I've always known it to work. I've never used PHP but surely the HTML specs. not having anything to say about PHP should not be a surprise? Isn't PHP a scripting language whose only connection with HTML is that it is embedded within HTML? > > > That's a possibility if you on forehand know the name(s) of checkboxes > > in your form. I was trying to make a general sql construction of an update > > statement independent of what might be in the form. !? > > Well, I don't know if you can get the variables in a hash, like in perl. > Another thing that sometimes works is: > > <input type=hidden name=box value=f> > <input type=checkbox name=box value=t> > > When the tickbox is ticked, the browser will return two values named "box", > which *may* cancel out to give you your t/f combo. > > Note this is extremely system specific and not guarenteed and not > recommended. But I have used it successfully on occasion. As Martijn says, this is all browser dependent stuff. The whole web thing works with servers not assuming anything about the client and you don't really want to start doing so. As for the general form handling issue how about having a table(s) holding definitions of forms which the form display page and the form target page can retrieve and do stuff with? Although generally aren't you going to want specialisations for most form handlers to implement their own validy checks etc. which will require knowledge in the PHP code somewhere about the form's details? Although for that I suppose it could be done client side in javascript held in the form definition table(s) but then you're back to the form handler making assumptions about the client. -- Nigel J. Andrews Director --- Logictree Systems Limited Computer Consultants
In HTML, unchecked checkboxes have no value. So you have to give them a value in the issuing page with hidden form fields or on the action page by setting a default variable value before your SGL insert query. Frank Hilliard http://frankhilliard.com
> > On Mon, 8 Apr 2002, Martijn van Oosterhout wrote: > > > On Mon, Apr 08, 2002 at 12:52:48PM +0200, Leif Jensen wrote: > > > I have looked in the HTML 4.0 recommendation, which talks about how > > > form data is being handled, but it doesn't say anything about how PHP > > > treats the result. > > > > Hmm, I'm not sure then, but this is the way I've always known it to work. > > I've never used PHP but surely the HTML specs. not having anything to say about > PHP should not be a surprise? Isn't PHP a scripting language whose only > connection with HTML is that it is embedded within HTML? True, PHP is a completely different beast from HTML. The HTML spec will not talk about it. Go to www.php.net and look at the manual. There's lots of good info there. Insofar as return values, you can use the "value=" clause of the checkbox to return whatever value you want when it has been "checked". If you want the checkbox to return something when it hasn't been checked, then prior to defining the checkbox, define a hidden type of the same name as your checkbox, but place the "unchecked" value in it. If the checkbox isn't checked then your default value gets returned by the browser, otherwise the value specified within the checkbox definition is returned. I think I found this on the PHP website several months ago. It works quite well. Shane
On Mon, 8 Apr 2002, S Dawalt wrote: > > Insofar as return values, you can use the "value=" clause of the checkbox > to return whatever value you want when it has been "checked". If you want > the checkbox to return something when it hasn't been checked, then prior to > defining the checkbox, define a hidden type of the same name as your > checkbox, but place the "unchecked" value in it. If the checkbox isn't > checked then your default value gets returned by the browser, otherwise the > value specified within the checkbox definition is returned. I think I > found this on the PHP website several months ago. It works quite well. Ok, but once again this is surely relying on browsers 'playing ball'. What happens if I use a browser that returns the hidden parameter with it's value whether or not the checkbox is checked, as it should? I'm guessing that since you mention the order in the form this is actually relying on the browser returning parameters in the order they occur within the form and the server providing only the latest definition to the application, the PHP action page. So what happens if I use a browser which returns parameters in some other order as one is perfectly entitled to do? What happens if the web server implements a 'first come first served' parameter setting scheme? Any, back to the original desire and to keep some what on topic, how about using a function installed in the DB server to perform the data validation? Or is the problem that PHP can't provide a null parameter to a function if there isn't a variable, from the form parameter, defined at the time of the call? Another or: isn't this also not helping towards the general form handling idea that is the real aim? -- Nigel J. Andrews Director --- Logictree Systems Limited Computer Consultants