topic Re: A strange thing about getting numbers of all library's datasets. in SAS Programming

A strange thing about getting numbers of all library's datasets.

Black — Sat, 09 Aug 2008 14:47:24 GMT

I want to get the numbers of all libraries' datasets. I can use there kinds of ways, as following:
proc sql noprint;
select count(memname)
into :numwk1
from sashelp.vstable;
quit;
%put &numwk1; /*-------------------------------------=3677*/

data _null_;
set sashelp.vstable end=eof;
retain count 0;
count+1;
if eof then do;
call symput('numwk2',left(count));
end;
run;
%put &numwk2; /*--------------------------------------=3677*/

data _null_;
if 0 then set sashelp.vstable nobs=a;
call symput('numwk3',a);
run;
%put &numwk3; /*--------------------------=9.0071993E15*/

Why the third answer is different with others?

Thanks a million.

Re: A strange thing about getting numbers of all library's datasets.

sbb — Sat, 09 Aug 2008 17:11:11 GMT

Ran your code. Did you notice the message below in your SASLOG?

NOTE: DATA STEP stopped due to looping.

Scott Barry
SBBWorks, Inc.

Re: A strange thing about getting numbers of all library's datasets.

Black — Sun, 10 Aug 2008 11:25:01 GMT

Thank you very much for your reminding.
I don't know why there is a looping here?
If i use this code to a normal data set, it is ok.
How could this looping happen?

Re: A strange thing about getting numbers of all library's datasets.

Black — Sun, 10 Aug 2008 11:28:27 GMT

If i change the code to this:
data _null_;
set sashelp.vstable nobs=a;
call symput('numwk3',a);
run;
%put &numwk3;
the result is still 9.0071E15.

very strange!

Re: A strange thing about getting numbers of all library's datasets.

Olivier — Sun, 10 Aug 2008 16:35:40 GMT

This is not so trange when you think that VSTABLE is a view, not a dataset. Being so, it cannot have the number of observations stored in a "contents" part of the physical file. Hence the wrong value, which must stand for "infinity", I think. Other solutions really count the records, so they give the correct answer.

And just a tip : the SASHELP views are based on SQL views stored in a pseudo library called DICTIONARY. For efficiency sake, you'd better change the first solution to FROM DICTIONARY.TABLES ; to avoid using one view on a view. Unfortunately, in a Data step, you are compelled to use the SASHELP views, since the DICTIONARY views are only available in an SQL query.

Regards
Olivier

Re: A strange thing about getting numbers of all library's datasets.

Black — Sun, 17 Aug 2008 15:08:36 GMT

Thank you, Olivier, you really got the point.

Re: A strange thing about getting numbers of all library's datasets.

deleted_user — Mon, 18 Aug 2008 11:43:53 GMT

Black

why not use proc contents or proc datasets or sashelp.vtable?

Of course a view does not store a count of the information it will provide when executed, but otherwise dictionary.tables surfaced as sashelp.vtable is very informative....
... so why do you want new code to provide this information ... ?

PeterC