ĵaŭ, 17 Dec 2009, christopher collins skribis:
NB. The insert below causes a failure
NB. After this the table can no longer be read.
NB. QUESTION: Is that behavior intended?
NB. If so, JDB seems a little fragile for the rough, unskilled hands
of newbies like me
NB. This insert, where '01' is
Thank you, Mr. Lam and Mr. Rufon and all others for your assistance
and instruction.
--chris--
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To: programming@jsoftware.com
Subject: [Jprogramming] Newbie JDB problem: inserting chars in a 1 column char
table gives 'assertion failure'
Thank you, Mr. Lam and Mr. Rufon and all others for your assistance
and instruction.
--chris
Hi -
The following appears to work OK:
Insert__db 'tblChar';,.'ABCDEF'
The ,. preceding the vector turns it into a 1-column matrix, which is
consistent with how the field is defined.
Reads__db '* from tblChar'
+--+
|c1|
+--+
|a |
|A |
|B |
|C |
|D |
|E |
|F |
+--+
Hope this helps.
On Tue,
Thanks to all for your help, especially Mr. Lam.
Your response, Mr. Lam, was very instructive.
I used your input to explore a bit more, with a couple of questions arising.
See the questions embedded below:
*
load 'data/jdb'
ffd =: Open_jdb_ jpath , '~temp'
Thanks for the help, Mr. Tirrell.
Does JDB have a way to declare the length of the char column?
I've gone through the JDB doc and sample code carefully and can't find
any indication of how to declare the length of the char column.
I've run a few experiments and can't get a JDB database table
I've not used JDB before but it's not clear from your post what exactly you are
trying to do.
You have declared a table consisting of one field that is a single character in
length.
Then you try to insert a record into the table that is multiple characters in
length.
Are you expecting
a) the
Sorry ignore my previous post. Having read your post more carefully I see that
you probably want to know how to do specify the max length of the field. (As I
said, I haven't used JDB before assumed that c1 was more than just the field
name).
Perhaps you checking out the demo databases that
: programming-boun...@jsoftware.com [programming-boun...@jsoftware.com] On
Behalf Of Sherlock, Ric [r.g.sherl...@massey.ac.nz]
Sent: Wednesday, December 16, 2009 9:35 AM
To: Programming forum
Subject: Re: [Jprogramming] Newbie JDB problem: inserting chars in a
1 column char table gives
Thank you Ric, for your suggestions.
I've reviewed the JDB doc carefully as well as all the example code
and haven't found the solution to my trivial problem.
Perhaps its there, but it is invisible to my J disabled cognition.
In my original post on this issue (Sent: Sunday, December 13, 2009
I don't use JDB either, however I guess you cannot declare a maximum length for
the literal string in char column. you might have to reshape rank-1 vector
before
inserting. eg.
ht=: Create__db 'tblChar2';'c1 char'
Insert__db 'tblChar2';'a'
Insert__db 'tblChar2';,'b'
Insert__db
Hi, I'm just starting to learn J and JDB.
I'm starting with the most trivial cases since they are best suited to
my trivial IQ.
I built a table with only 1 column defined as datatype char.
I was successful in inserting a single character with each insert statement.
However, when I tried
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