Compare Memo Fields

[Jerry Gray]

There have been several threads on audit trails and the fact that A5V5 won't/can't compare memo fields. Well it appears the same is true in V6.

One of my files to be audited has a single memo field which may contain 2000 characters or more and yes, it needs to be audited.

One of my other files to be audited has 3 memo fields, all of which need to be audited.

Has anyone found a workable solution for comparing memo fields? Do I have to write the memo field to a text file then do a line by line comparison? Is there a way to compress the field then compare it in compressed format?

Any help would be appreciated.

Jerry Gray

[Al Lenkner]

RE: Compare Memo Fields

Jerry,

I'm new to Alpha so I may be wrong. I don't understand what you mean when you say "audited". If I wanted to compare two memo fields in Alpha, I presume that you could place the memo fields into string variables and then compare the strings. If you have to compare one or more against all of the memos, I think an array would be the way to go. Everything in memory would be quicker than reading from your hard drive (if you have the memory).

[Jerry Gray]

RE: Compare Memo Fields

Al,

Apparently memo fields are different animals in that they can hold an unlimited amount of information.

I assume that there are other reasons why they can't be compared or the Alpha Gurus would have added that functionality.

Hope this makes it more clear and doesn't just muddy the water for you.

Jerry Gray

[csda1]

RE: Compare Memo Fields

Jerry,

They sure can be compared. I do it all the times. You have to move the contents of the memo field to a blob variable and compare them, but it will work even with binary data. There are other methods as well, all depending on what you want to do. A binary compare is relatively easy.

Regards,

Ira

[Jerry Gray]

RE: Compare Memo Fields

Ira,

I'm using the basic script from Dr. Peter Wayne's book. I should be able to test for the memo field right after it tests for the STATUS field. If it is the memo field, copy it to the blob, compare and save if necessary and continue. Is this right?

Thanks for your help,
Jerry Gray

[Jerry Gray]

RE: Compare Memo Fields

Ira,

I have attached my script for my audit trail.

"FIELD".VALUE_GET()
"FIELD".INITIAL_VALUE_GET()

These two functions do not return the same type of data when used against a Memo field (not RTF). I've tried putting the returned value into both a Character and Blob variable. Both generated a "Variable type mismatch" error.

My script is being played from the Record Events in the Field Rules of my primary file.

I just need to get both the current and initial values into like formats so I can compare them.

I am using the latest patch of V6, build: 1536...2011
Windows XP Pro, SP2 installed (yeah, I know)

Anyone have any ideas?

I don't have V5 to test if the results are the same in an earlier version.

I don't have a lot of hair left to pull out ;")

Thanks,
Jerry Gray

[Jerry Gray]

RE: Compare Memo Fields

For anyone who is trying to use the "FIELD".INITIAL_VALUE_GET() on a memo field!

Selwyn has informed me that the "FIELD".INITIAL_VALUE_GET() does not work with memo fields. He is checking into it.

Jerry

[Tom Cone Jr]

RE: Compare Memo Fields

Has this been fixed?

Is there a work around?

-- t

[Jerry Gray]

RE: Compare Memo Fields

Tom,

I never heard any more on this issue. Selwyn gave me a workaround to get the initials value of the memo field. I am using it for auditing records. Following you will find the code that is placed in the CanEnterRecord and CanChangeRecord events. The second part is an excerpt showing the comparison of the before and after value of the memo field.

In the Field Rules for the file
Both CanEnterRecord and CanChangeRecord events
------------------------------------------------------------
dim shared Memo1_Init_Value as c

dim t as p
dim f_memo1 as p

t = table.current()

f_memo1 = t.field_get("Incident_Desc")

Memo1_Init_Value = f_memo1.value_get()

------------------------------------------------------------
In the Field Rules for the file
CanSaveRecord event
Run This Script
------------------------------------------------------------

dim shared Memo1_Init_Value as c

dim tbl as p
DIM audit AS P
DIM mode AS n

DIM i_Incident_Desc AS b

DIM c_Incident_Desc AS c

tbl=table.current()
mode=tbl.mode_get()
'mode of 1 is a change, 2 is a new entry ; deleted records on CanDelete field rule

audit = table.open("Incident_audit",FILE_RW_SHARED)
audit.enter_begin()

c_Incident_Desc = tbl.eval("Incident_Desc")

dim blank_Date as d

if mode=1 then
'if the initial value equals the current value, save as blank else save the current value
audit.INCIDENT_DESC = if(i_Incident_Desc=c_Incident_Desc," ",c_Incident_Desc)
audit.Status="C"

elseif mode=2 then

audit.Incident_Desc = tbl.eval("Incident_Desc")
audit.Status="E"

end if
audit.enter_end()
audit.close()

--------------------
If this isn't clear, let me know and I will send you a straight email where the indentations help make it easier to read.

Hope this helps,
Jerry Gray

[Tom Cone Jr]

RE: Compare Memo Fields

Jerry, thanks!

-- t

[Gary Bangoy]

RE: Compare Memo Fields

Tom,

Jerry Gray's approach might be a better work around for me. I guess I'm convinced there is a bug in the .initial_value_get() method. Gerard Lynne reported that he was able to get it work with A5V4.

Regards,
Gary

[Jerry Gray]

RE: Compare Memo Fields

Gary,

Selwyn did say that it doesn't work with memo fields. What he didn't say was if it was intended to work with memo fields or if will in the future.

Later,
Jerry Gray

[Jerry Gray]

RE: Compare Memo Fields

Tom,

I'm just glad I had something to contribute that someone else could use.

Jerry Gray

[Tom Cone Jr]

RE: Compare Memo Fields

Jerry,

Me, too! :)

-- t

[Jerry Gray]

RE: Compare Memo Fields

According to the release notes Build 1544-2027 - 19-Nov-2004:

"FLD".Initial_value_get() Method - This method now works for Memo fields.


Thought you might want to know...

Jerry Gray