Re: Loading image data from DB

[Devin Asay]

Thanks, Jeanne. I suppose one of the drawbacks of high level  
programming is that it insulates us so much from the ones and zeros  
that those of us who came into x-talking from a non-programming  
background never quite got some of the fundamentals. As this example  
shows, there are times when understanding the basics make the  
difference between success and failure.


Devin

On Apr 11, 2006, at 7:42 PM, Jeanne A. E. DeVoto wrote:


At 10:47 AM -0600 4/7/2006, Devin Asay wrote:
Which is essentially what I ended up doing, and it worked. Is it  
correct to assume that 'the text' is binary data expressed as  
ASCII text and data like 'the imageData' is lower-level code  
that can't be expressed visually in a meaningful way? Forgive my  
naive non-techie questions.


Not exactly - any binary data can be expressed in terms of ASCII  
(or extended ASCII) characters. Looking at an example:


A typical byte's worth of binary data (8 bits): 01101101
That same binary number, expressed in decimal (ordinary base-10  
numbers): 64 + 32 + 8 + 4 + 1, or 109
ASCII 109 is the character m, so we could write that byte's worth  
of binary data as m.


Any 8-bit segment of binary data can be expressed as a single ASCII  
character, in the same fashion, so we can always represent binary  
data as characters. The main fly in the ointment is that some of  
those characters are control characters, or characters that don't  
have a glyph to represent them, and some of those will cause real  
trouble if you try to e.g. display them in a field. (For example,  
the binary sequence  is perfectly valid and may show up  
in the binary data of any picture, but the character it's  
equivalent to is the null character, ASCII 0 - which can't be  
displayed on screen.)


This is the basic difference between binary data and text data  
- you can represent either one of them as either strings of ones  
and zeroes, or as sequences of ASCII characters, but text is  
guaranteed to contain only characters in the subset that can be  
represented in a text file, whereas in binary data, anything goes,  
and a sequence of 8 bits might translate into any character.



Am I correct in my understanding that these two statements are  
functionally identical:


put myData into image myImage
set the text of image myImage to myData

?

In other words, 'put' is simply shorthand for 'set the text of  
object'?


Yes. The text property of a container object (an image, button, or  
field) is the same as a reference to that object. It works for  
images just like for fields.


Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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Re: Loading image data from DB

[Jeanne A. E. DeVoto]

At 10:47 AM -0600 4/7/2006, Devin Asay wrote:
Which is essentially what I ended up doing, and it worked. Is it 
correct to assume that 'the text' is binary data expressed as ASCII 
text and data like 'the imageData' is lower-level code that can't 
be expressed visually in a meaningful way? Forgive my naive 
non-techie questions.


Not exactly - any binary data can be expressed in terms of ASCII (or 
extended ASCII) characters. Looking at an example:


A typical byte's worth of binary data (8 bits): 01101101
That same binary number, expressed in decimal (ordinary base-10 
numbers): 64 + 32 + 8 + 4 + 1, or 109
ASCII 109 is the character m, so we could write that byte's worth 
of binary data as m.


Any 8-bit segment of binary data can be expressed as a single ASCII 
character, in the same fashion, so we can always represent binary 
data as characters. The main fly in the ointment is that some of 
those characters are control characters, or characters that don't 
have a glyph to represent them, and some of those will cause real 
trouble if you try to e.g. display them in a field. (For example, the 
binary sequence  is perfectly valid and may show up in the 
binary data of any picture, but the character it's equivalent to is 
the null character, ASCII 0 - which can't be displayed on screen.)


This is the basic difference between binary data and text data - 
you can represent either one of them as either strings of ones and 
zeroes, or as sequences of ASCII characters, but text is guaranteed 
to contain only characters in the subset that can be represented in a 
text file, whereas in binary data, anything goes, and a sequence of 8 
bits might translate into any character.



Am I correct in my understanding that these two statements are 
functionally identical:


put myData into image myImage
set the text of image myImage to myData

?

In other words, 'put' is simply shorthand for 'set the text of object'?


Yes. The text property of a container object (an image, button, or 
field) is the same as a reference to that object. It works for images 
just like for fields.

--
jeanne a. e. devoto ~ [EMAIL PROTECTED]
http://www.jaedworks.com
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Re: Loading image data from DB

[Rob Cozens]

Devin,

The trick seems to be that you upload and download the image data as 
*text* (as opposed to the imageData of the image, which is binary.) I 
may have this all wrong conceptually, but that's how it finally made 
sense to me.


An image's Text property is  binary data that comprises the image.  
The problem arises because, until one reads the Dictionary, one might 
easily assume an image's Text property contains text, just like a 
field.


So, just as one might...

get URL ((file:textFileName))
put it into field Main Text

one should be able to (untested)

get URL ((binfile:imageFileName))
put it into image Main Image


Rob Cozens
CCW, Serendipity Software Company

And I, which was two fooles, do so grow three;
Who are a little wise, the best fooles bee.

from The Triple Foole by John Donne (1572-1631)

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Re: Loading image data from DB

[Devin Asay]

On Apr 7, 2006, at 10:32 AM, Rob Cozens wrote:



Devin,

The trick seems to be that you upload and download the image data  
as *text* (as opposed to the imageData of the image, which is  
binary.) I may have this all wrong conceptually, but that's how it  
finally made sense to me.


An image's Text property is  binary data that comprises the  
image.  The problem arises because, until one reads the Dictionary,  
one might easily assume an image's Text property contains text,  
just like a field.


So, just as one might...

get URL ((file:textFileName))
put it into field Main Text

one should be able to (untested)

get URL ((binfile:imageFileName))
put it into image Main Image


Which is essentially what I ended up doing, and it worked. Is it  
correct to assume that 'the text' is binary data expressed as ASCII  
text and data like 'the imageData' is lower-level code that can't  
be expressed visually in a meaningful way? Forgive my naive non- 
techie questions.


Am I correct in my understanding that these two statements are  
functionally identical:


put myData into image myImage
set the text of image myImage to myData

?

In other words, 'put' is simply shorthand for 'set the text of  
object'?


Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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Re: Loading image data from DB

[Rob Cozens]

Devin,

Is it correct to assume that 'the text' is binary data expressed as 
ASCII text and data like 'the imageData' is lower-level code that 
can't be expressed visually in a meaningful way?


My assumption is the image's Text is identical to the content of the 
gif, jpeg, or whatever image file it was loaded from.


The imageData is in rev-proprietary format regardless of original image 
type, and it contains the image at the size and resolution it is 
displayed on the screen.


Rob Cozens
CCW, Serendipity Software Company

And I, which was two fooles, do so grow three;
Who are a little wise, the best fooles bee.

from The Triple Foole by John Donne (1572-1631)

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Re: Loading image data from DB

[Rob Cozens]

All:


put the imageData of image picImage into tBits


I asked this question before, and I still haven't gotten to the point 
of testing:


Why does everyone choose the imageData of the image instead of its text?

From Rev Dictionary:

The imageData, unlike the contents of the image container, is based on 
the picture as it’s presented on the screen, not stored in the image 
object. This means that if you resize an image, the content of the 
image does not change, but its imageData does. If you create an image 
and then reduce its size, its imageData reflects the scaled-down, 
displayed image, not the original full-scale image. If you create a 
second image and set its imageData property to the imageData of the 
original image, resizing the first image back to the original 
dimensions displays the original image at full resolution, but resizing 
the second image does not, because setting its imageData transferred 
only the scaled-down version of the original.


I read this to say, If you want to retain the original contents of an 
image, store its text NOT its imageData.


What am I missing?

Rob Cozens
CCW, Serendipity Software Company

And I, which was two fooles, do so grow three;
Who are a little wise, the best fooles bee.

from The Triple Foole by John Donne (1572-1631)



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Re: Loading image data from DB

[Devin Asay]

Thanks to Chris and Rob I've got this working. Rob proves once again  
how reading the blinking manual can make you look like a genius. (Not  
to imply that Rob is not one, just that in addition to his native  
intelligence he has a passel of common sense.)


Chris's contribution was a necessary part of the solution:

On Apr 5, 2006, at 8:32 PM, chris bohnert wrote:

when returning the data i do

put select name,imageData from limage where name='  tImgName  
' into tsql

put revdb_queryblob(tconnectionid,tsql) into tRS
if not revdb_iseof(tRS) then
 put revDatabaseColumnNamed(tRS,name,tPicName)
 set the text of field strPicName to tPicName
 put revDatabaseColumnNamed(tRS,imageData,tImageDat)
 set the imagedata of image picImage to tImageDat
 answer got a result
   end if


But I was only getting a band of random colors on the edge of my  
image object. Then Rob provided the final piece:


On Apr 6, 2006, at 9:18 AM, Rob Cozens wrote:


All:


put the imageData of image picImage into tBits


I asked this question before, and I still haven't gotten to the  
point of testing:


Why does everyone choose the imageData of the image instead of its  
text?


From Rev Dictionary:


snip


I read this to say, If you want to retain the original contents of  
an image, store its text NOT its imageData.


My final solution for loading an image from a database looks like this:

  put word 2 of the selectedline of fld linenumbers into tEntryNum
  put select illustration from vocablist where item_index='   
tEntryNum ' into tsql

  put revdb_queryblob(connID,tsql) into tRS
  if not revdb_iseof(tRS) then
put revDatabaseColumnNamed(tRS,illustration,tImageDat)
put tImageDat into image testImg
  end if

Thanks again.

Devin

Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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Re: Loading image data from DB

[Rob Cozens]

Shucks,  Devin

Rob proves once again how reading the blinking manual can make you 
look like a genius. (Not to imply that Rob is not one,


Even a Triple Foole can come off looking smart once in a while.   :{`)

Rob

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Re: Loading image data from DB

[Mark Wieder]

Rob-

Thursday, April 6, 2006, 8:47:40 AM, you wrote:

 Even a Triple Foole can come off looking smart once in a while.   :{`)

...gotta watch it or you'll lose your amateur standing...

-- 
-Mark Wieder
 [EMAIL PROTECTED]

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Re: Loading image data from DB

[Devin Asay]

Now I've figured out the other half of this cycle: how to upload  
image data to a database. The trick seems to be that you upload and  
download the image data as *text* (as opposed to the imageData of the  
image, which is binary.) I may have this all wrong conceptually, but  
that's how it finally made sense to me. This is how I'm doing it for  
files external to the stack:


  put fld entryNumber into tEntryNum
  put binfile:  the filename of image testImg into fileNm
  put url fileNm into tBits
  put update vocablist set illustration = :1 where item_index='   
tEntryNum  ' into tQuery
  get revdb_execute(connID, tQuery,*btBits) -- (*b tells it to  
send the text as a binary stream.)


For internal files this worked:

  put fld entryNumber into tEntryNum
  put image leaf into tBits
  put update vocablist set illustration = :1 where item_index='   
tEntryNum  ' into tQuery

  get revdb_execute(connID, tQuery,*btBits)

I hope this saves someone some time and frustration.

Devin

Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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Loading image data from DB

[Devin Asay]

I know this can be done, but it's got me stumped. Nothing conclusive  
from archives.


I want to store image data in a  mysql database and then show it in  
an image object in Rev. I successfully loaded an image into a field  
of type longblob. I know the data is there and that it's valid.


This is what I tried to load the image data:

global connID -- my connection id

on mouseUp
  if connID is empty then
answer You need to connect to the database first.
exit to top
  end if
  put word 2 of the selectedline of fld linenumbers into tEntryNum
  put select illustration from vocablist where item_index =
tEntryNum into tQuery

  put revDataFromQuery(,,connID,tQuery) into tData
  set the imagedata of img testImg to tData
end mouseUp

The query ends up something like this:

select illustration from vocablist where item_index = 1290

All I ever get in the tData variable is four random characters; ˇÿˇ‡

I know the image data in the database table is valid because I can  
set up an automatic query in the Database Query Builder, then set the  
image object to automatically load that data, and it works. I've  
tried to find the scripting in the Database Query Builder stack that  
does this, but no luck.


Has anyone successfully done this who can share the secret to making  
it work?


Thanks,

Devin

Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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Re: Loading image data from DB

[Dave Cragg]

On 5 Apr 2006, at 23:37, Devin Asay wrote:

I know this can be done, but it's got me stumped. Nothing  
conclusive from archives.


I want to store image data in a  mysql database and then show it in  
an image object in Rev. I successfully loaded an image into a field  
of type longblob. I know the data is there and that it's valid.


This is what I tried to load the image data:

global connID -- my connection id

on mouseUp
  if connID is empty then
answer You need to connect to the database first.
exit to top
  end if
  put word 2 of the selectedline of fld linenumbers into tEntryNum
  put select illustration from vocablist where item_index =
tEntryNum into tQuery

  put revDataFromQuery(,,connID,tQuery) into tData
  set the imagedata of img testImg to tData
end mouseUp


Did you try using revQueryDatabaseBlob instead of revDataFromQuery?

Cheers
Dave
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Re: Loading image data from DB

[Trevor DeVore]

On Apr 5, 2006, at 3:37 PM, Devin Asay wrote:

I know this can be done, but it's got me stumped. Nothing  
conclusive from archives.


I want to store image data in a  mysql database and then show it in  
an image object in Rev. I successfully loaded an image into a field  
of type longblob. I know the data is there and that it's valid.


...
Has anyone successfully done this who can share the secret to  
making it work?


Devin,

I think there is a bug when retrieving binary data using the mysql  
driver.  If you get it to work I would like to know.  I messed with  
this briefly the other day and couldn't get the binary data out that  
I put in.


--
Trevor DeVore
Blue Mango Learning Systems - www.bluemangolearning.com
[EMAIL PROTECTED]


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Re: Loading image data from DB

[Devin Asay]

On Apr 5, 2006, at 4:55 PM, Dave Cragg wrote:



On 5 Apr 2006, at 23:37, Devin Asay wrote:

I know this can be done, but it's got me stumped. Nothing  
conclusive from archives.


I want to store image data in a  mysql database and then show it  
in an image object in Rev. I successfully loaded an image into a  
field of type longblob. I know the data is there and that it's valid.


This is what I tried to load the image data:

global connID -- my connection id

on mouseUp
  if connID is empty then
answer You need to connect to the database first.
exit to top
  end if
  put word 2 of the selectedline of fld linenumbers into tEntryNum
  put select illustration from vocablist where item_index =
tEntryNum into tQuery

  put revDataFromQuery(,,connID,tQuery) into tData
  set the imagedata of img testImg to tData
end mouseUp


Did you try using revQueryDatabaseBlob instead of revDataFromQuery?


Yep. I tried it. Same results.

Devin

Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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Re: Loading image data from DB

[Devin Asay]

On Apr 5, 2006, at 5:43 PM, Trevor DeVore wrote:



On Apr 5, 2006, at 3:37 PM, Devin Asay wrote:

I know this can be done, but it's got me stumped. Nothing  
conclusive from archives.


I want to store image data in a  mysql database and then show it  
in an image object in Rev. I successfully loaded an image into a  
field of type longblob. I know the data is there and that it's valid.


...
Has anyone successfully done this who can share the secret to  
making it work?


Devin,

I think there is a bug when retrieving binary data using the mysql  
driver.  If you get it to work I would like to know.  I messed with  
this briefly the other day and couldn't get the binary data out  
that I put in.


--
Trevor DeVore


Well, at least I'm not alone in this. What puzzles me is that it  
works flawlessly when I set up an automatic query in Database Query  
Manager. I tried and failed to find the script that executes the  
query in the DQM stacks. I'll Bugzilla this if there isn't already a  
bug report on it. Anyone know?


Devin

Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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Re: Loading image data from DB

[chris bohnert]

The only way i've ever been able to get this to work is by using the 
variable binding when inserting data into the blob.  By using the *b 
prefix on the variable name in the execute parameter the binary encoding 
routines kick in.


put the imageData of image picImage into tBits
put the text of field strPicName into tName
get revdb_execute(tconnectionid, insert into limage(name,imageData) 
values(:1,:2),tName,*btBits)


then when returning the data i do

put select name,imageData from limage where name='  tImgName ' 
into tsql

put revdb_queryblob(tconnectionid,tsql) into tRS
if not revdb_iseof(tRS) then
 put revDatabaseColumnNamed(tRS,name,tPicName)
 set the text of field strPicName to tPicName
 put revDatabaseColumnNamed(tRS,imageData,tImageDat)
 set the imagedata of image picImage to tImageDat
 answer got a result
   end if


--
cb

Devin Asay wrote:


On Apr 5, 2006, at 5:43 PM, Trevor DeVore wrote:



On Apr 5, 2006, at 3:37 PM, Devin Asay wrote:

I know this can be done, but it's got me stumped. Nothing conclusive 
from archives.


I want to store image data in a  mysql database and then show it in 
an image object in Rev. I successfully loaded an image into a field 
of type longblob. I know the data is there and that it's valid.


...
Has anyone successfully done this who can share the secret to making 
it work?


Devin,

I think there is a bug when retrieving binary data using the mysql 
driver.  If you get it to work I would like to know.  I messed with 
this briefly the other day and couldn't get the binary data out that 
I put in.


--Trevor DeVore


Well, at least I'm not alone in this. What puzzles me is that it works 
flawlessly when I set up an automatic query in Database Query Manager. 
I tried and failed to find the script that executes the query in the 
DQM stacks. I'll Bugzilla this if there isn't already a bug report on 
it. Anyone know?


Devin

Devin Asay
Humanities Technology and Research Support Center
Brigham Young University

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