Unable to set column of type image to empty in DBTreeView

Classic Servoy
1

Hi All

I am unable to fill in programmatically an icon as empty in a DBTreeView bean.

Column name: icon : type is image (Database SQL Anywhere 10)

When the bindig to the icon was made in the bean setup, there is by default an empty icon inserted (icon is a sheet of paper). I can suppress that with the SQL stmt for example:

UPDATE school_units set icon = ‘’
where id = 44;

Works perfect, i. e. the icon is not shown any more.

Now I do that on entering a new record with the JavaScript line:

icon = ‘’;

Doesn’t work, i. e. the column value is null, hence the empty icon is shown.

That means the ‘’ in JavaScript is not equivalent with the ‘’ in a SQL statement.

Anyone knows the equivalent in JavaScript?

Best regards, Robert

PS: The DBTreeView shown in attachment as example:
Row Maturitätsschule with icon = empty
Row yyy with icon = null, i. e. showing as defautl (white sheet of paper)

Picture 1.png
Picture 1.png417×348 21.6 KB

2

Have your tried:

icon = new String();

I don’t know the SQL Servoy will generate on that, but at least icon won’t be null.

Hope this helps,

3

If nothing else works you could consider using a 1x1 px transparent png image as workaround
It won’t hurt the speed (size-wise) and it’ll solve your problem…

4

In any case file a bug report for this because if you set an empty string to a dataprovider then you don’t want it to store a NULL.
An empty string is not equal to a NULL, in any language ;)

5

Setting empty strings to a blob column can cause errors in many environments (for example you get an error if you do that with .NET and SQL Server). I find it a bit strange, anyway, to assign an empty string to a blob column…

6

Oh, wait. A BLOB column ? I thought this was a text column.

7

Hi Marc

I was looking for a better solution .-) But I know it’s common in HTML programming…

Regards, Robert

mboegem:
If nothing else works you could consider using a 1x1 px transparent png image as workaround
It won’t hurt the speed (size-wise) and it’ll solve your problem…

8

I absolutely agree with your conclusion, did I say otherwise? I hope not :D

ROCLASI:
In any case file a bug report for this because if you set an empty string to a dataprovider then you don’t want it to store a NULL.
An empty string is not equal to a NULL, in any language ;)

9

Hi Patrick

I do not want to assign a string to an image type column, but I am looking for the equivalent of an empty (not null) image (first sentence in my original post) and couldn’t find one till now.
But I still hope to find it :)

Regards, Robert

patrick:
Setting empty strings to a blob column can cause errors in many environments (for example you get an error if you do that with .NET and SQL Server). I find it a bit strange, anyway, to assign an empty string to a blob column…

10

No, it’s a column of type image (in SQL Anywhere)

ROCLASI:
Oh, wait. A BLOB column ? I thought this was a text column.

11

But that is basically the same! According to Sybase:

The IMAGE data type is used to store binary data of arbitrary length

Empty Strings are not exactly that.

12

Hi Patrick, your idea does not work, either. Thanks, Robert

ptalbot:
Have your tried:

icon = new String();

I don’t know the SQL Servoy will generate on that, but at least icon won’t be null.

Hope this helps,

13

I completely agree with you, Patrick, but what is the (Hex) code of an empty image, so I do NOT get the default icon of the DBTreeView bean? I tried some variant of 0x00 etc., but nothing works so far. And I am asking myself how I exactly would make an empty media which is not at least 1 px width as suggest by Marc. If I can set it with an SQL command, it should be possible to assign a value to the icon column with just that. I only can’t decode the ‘’ entered with SQL, if I would find a way that would be the solution.

Thanks, Robert

patrick:
But that is basically the same! According to Sybase:

The IMAGE data type is used to store binary data of arbitrary length

Empty Strings are not exactly that.

14

Hi All

I noticed that I am not able to assign ANY media to a database field. As with other database columns of datatype integer or varchar, for example, I try to assign the db column icon of datatype image this:

icon = "media:///icnTransparent1x16.png";

But it doesn’t work!? What’s wrong here?

Any help very appreciated, Robert

15

What you are assigning is a string. You have to make sure that you are passing a byte. So in your case you should do something like

icon = plugins.http.getMediaData('media:///yourImage.png');
16

Hi Patrick

That was it - thanks a lot! One step further :D
I am assigning a transparent image of size 1 px width x 16 px height. This in fact needs (measured on the screen) 2 px width, for whatever reason!?
Now, if I only knew how to assign an “empty” image which does not consume any width in the DBTreeView row at all, like when I insert an “empty” image into the row with the SQL stmt

update school_units
set icon = ‘’
where id =

This does not consume any width, except the default indent, of course.

Best regards, Robert

PS: BTW, is my assumption correct that we can’t control the indentation in DBTreeView? Did anybody make a request for that already?

17

Just leaving your blob struggles aside: what exactly do you want to do?

18

I just want to waste as little horizontal space per (inserted) row as possible. And I do not want to have the default paper or folder icon to be displayed in the tree. As the indent is already quite big, I do not want to loose even more space. That’s all I try to achieve.

Best regards, Robert

patrick:
Just leaving your blob struggles aside: what exactly do you want to do?

19

Is it that you don’t want any icons at all or just in some cases (for some nodes)?

20

For one DBTreeView I do not want icons at all, for the other one it’s mixed, i. e. some nodes have an icon, some don’t.

patrick:
Is it that you don’t want any icons at all or just in some cases (for some nodes)?