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microsoft access file with long binary data field

P: 1
Hello,

I have a microsoft access file with fields that have "long binary data". I would like keep the same file, but change the "long binary data" into regular text. There are a large number of fields, so it needs to automated. I'm not a programmer, but a network engineer. Is there any way to do this without programming? Thank you, Ken
Mar 27 '10 #1
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9 Replies


Expert Mod 2.5K+
P: 2,545
Hi Ken.

Before you can do anything to convert your data you must have a clear understanding of its structure. What you mean when you say 'long binary data' is unclear; long as in a 256-bit sequence, say? Or a 1024-bit data packet? Or Long as in Long Integer? If you simply want to convert long integer fields in a table to text you could take a copy of the table then change the field type from long to text. Job done. Or, you could use a query to convert the data type without changing the table at all, using the CStr function for example to convert to string format.

Otherwise, you will need to have a clear understanding of what the actual structure of your binary data is before you begin.

Even if you do have a clear understanding of the data, trying to represent binary data in ASCII text format is not generally at all successful. An 8-bit byte can take any value between 0 and 255, but ASCII's viewable character range is from 32 to 126 (excluding the extended ASCII codes from 128 to 254 which generate block lines and other special characters).

As ASCII was originally a 7-bit code its values stopped at 127. Later developments have extended that range, and the much-later Unicode representations of text have done away with ASCII restrictions, but as you are simply wishing to convert binary to text there is little point in considering these at present.

Even within ASCII's original range many valid ASCII values cannot be represented as viewable text (the control characters such as CR and LF, for instance).

It is possible of course to convert one format of data to another, but whether you will see anything meaningful by doing so is another matter.

I can't be more specific without knowing the structure of the binary data to which you refer.

Welcome to Bytes!

-Stewart
Mar 27 '10 #2

ADezii
Expert 5K+
P: 8,597
Access typically displays the text "Long Binary Data" in a field when it contains a BLOB (Binary Large Object). A BLOB can be any type of binary data, and is most commonly a copy of a file, such as a JPEG photo or other Graphic Image. The BLOB field contains a Byte-for-Byte copy of the file, so it can easily be extracted back to the File System resulting in an identical copy of the original file.

Are you speaking about converting the Long Binary Data Type Fields back to their original Files? If this is the case, do you know the Extension and/or FileNames associated with each Binary Field?
Mar 27 '10 #3

P: 5
I am having the same problem.

@ADezii, I do not know what type of file of the original file attached to the Long Binary Data. Is there a way to identify this?
Jun 25 '10 #4

ADezii
Expert 5K+
P: 8,597
@xtep2010
There must be some kind of Unique Identifier in the File's Header, but I am not sure as to where in the File (Offset) it may be. I'll look into this a little more when I have the chance.
Jun 25 '10 #5

P: 5
@ADezii
@ADezii, I tried extracting it to .txt file and the content is
 + : I Z `
Jun 26 '10 #6

ADezii
Expert 5K+
P: 8,597
@xtep2010
If it is in a Long Binary Data Format, chances are that the majority of Characters would be unreadable. What I can do is to Output the contents of each Long Binary Data Field to a Unique File Name with the generic Extension of *.dat (<Primary Key>.dat). You can then try to Open each File with various Apps in order to determine what kind of Extension should be associated with it, namely: *.jpg, *.bmp, *.txt, *.doc, etc. I won't attempt this unless you are actually interested.
Jun 26 '10 #7

P: 5
@ADezii
I have tried it already.. it seems the data that was saved in the ms access database is compressed or encrypted..
Jun 26 '10 #8

ADezii
Expert 5K+
P: 8,597
@xtep2010
Gotcha, thanks for saving me some trouble (LOL).
Jun 26 '10 #9

P: 5
@ADezii
Can you help me with this?
Jun 27 '10 #10

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