InfoQube IM - Community

Submitted by Armando on 2010/01/24 18:56

Seems like that the null=0 spec is only for certain calculations as (even when null=0) if I put a filter condition like x<100 in a grid, items with nothing (null) in a fieldwon't appear, as if they were not = 0 but really NULL. This is expected only if null=o is only true in certain cases... Like horizontal calculations.

Maybe a note or popup in the manage field dialog ?

Comments

(from here: www.sqlnotes.net/drupal5/index.php )

[quote=Tom]

[quote=grahamrhind]

3) In the properties pane, Forms->Grid Form, double clicking should "Show items with values for this field". 0 is a value, as is False in a Boolean field, but in both cases these are excluded when that is chosen. It took me a while to work out where my data had "gone". I think this either needs correcting or the explanation improved.

[/quote]

I had trouble with this lately - AFAIK if you filter a grid for a numeric field having a value, items with a value of '0' dont get displayed (I dont think this is changed by the option to make 'Null=0' )

I'll have to look up my notes though or try it out again...

well a quick check confirms that if the source is a numeric field, items with a value of '0' dont get displayed, whether the option 'Null=0' is selected or not

[/quote]

I was stumped by this lately cause some items had a value of nought in a numeric field - as opposed to having no value.

I wanted these items included when I made said numeric field the grid-source ...

[quote=Tom]

1- Actually, item with a value of 0 are displayed. There are no reasons why it wouldn't.

e.g : urgency = 0 will display all those corresponding fields in my DB.

Are you sure you filtered correctly ?

2- As for the Boolean fields with a value of "false" (0) not being shown when double clicking in the properties pane -- this should probably just be rephrased. But IMO, unless you think very technically about it, it's pretty straight forward : you can check a check box or leave it empty as far as the UI is concerned, so, intuitively, most users will not expect to see "unchecked fields" appearing if they double click in the properties pane.

But what do others think ?

[quote=Armando]

[quote=Tom]

1- Actually, item with a value of 0 are displayed. There are no reasons why it wouldn't.

e.g : urgency = 0 will display all those corresponding fields in my DB.

Are you sure you filtered correctly ?

[/quote]

just checked again - it's with the numeric field as source that I have a problem:-

"well a quick check confirms that if the source is a numeric field, items with a value of '0' dont get displayed, whether the option 'Null=0' is selected or not"

[quote=Tom]

just checked again - it's with the numeric field as source that I have a problem:-

"well a quick check confirms that if the source is a numeric field, items with a value of '0' dont get displayed, whether the option 'Null=0' is selected or not"

[/quote]

Hmmmm... I tried setting urgency = 0 in the source and everything happens as expected : items with an urgency = 0 are shown...

(The red flag is the urgency field)

I wonder what's happening.

Can you post a screen shot ?

[quote=Armando]

I wonder what's happening.

Can you post a screen shot ?

[/quote]

I'm sorry Armando, I wasnt specific enough

Take any Numeric Field - my example here is Features
Give some items a value of '0' (zero) in that field
Make that field the source ( i.e. Features )
Items with entry of '0' dont show in the grid

I have tried this changing the option "Null=0" without any effect (but didnt restart in between). Currently my 'Test' field has that option deselected (I have no idea if that option has an effect here - hence my posting)

Sorry Tom... Now I understand what you mean. Yes. This is probably another bug though, and not the same as the issue I described in the firs post. It deserves its own thread... :)

Agreed. Currently you need to type: Features is not null for it to work. I'll look into it, but it seems an SQL thing

[edit] It is an SQL thing and I'll need to find a workaround: A field with no criteria get translated to Field <> false, but since false =0, it omits all items with field=0 [/edit]

I see.

However, isn't this different from what I mentioned in the first place ? Just to make sure we're not mixing issues here...

Null=0 does 1 and only 1 thing:

When expressions are expanded (row and column calc: actual values are inserted in the equation in preparation for the equation evaluation), what should be done when an item has no value
1. Null=0 checked: field-values with no values are replaced by zero: this can affect averages, counts, but has no impact on sums
2. Null=0 unchecked: field-values with no values are replaced by Null: Well written VBScript will test for Null and act accordingly. Improperly handled, it can cause Null propagation.

HTH

Thanks Pierre, I kinda discovered that through trial and error... And because you explained it to me already in the past. ;)

My point was more that the effect of the "Null = 0" should me be made more explicit somewhere in the interface -- hence my proposition of explaining it in a popup or something like that. IMO, IQ must avoid any ambiguities as far as options and their effect are concerned.

In any case, I'll try to find a spot in the manual for your Null=0 explanation.

I've moved this to the Equations section and changed to a more descriptive text

Seems good to me -- both because of the new placement and the description.