Conditionally assign a library?

[MrsC]

Is there a way to conditionally assign a library?  I have an EG project (egp file) with a prompt, and I want the user to pick which of 4 databases they want to connect to.  If they pick 2, then I only want to invoke the libname statements for the 2 they selected.  I have 4 macro variables that indicate whether they want the library assigned or not.

It is not working to put the libname statement in a select or an if-then-else because it gets invoked regardless.

[smantha · Accepted solution]

Can you show some code. If mac variables are mac1 , mac2, mac3 and mac4 and they have a boolean of YES or NO you can do the following

%macro assign_libname;
%if &mac1 = YES %then %do;
data _NULL_;
call execute(<libname statement 1>);
run;
%end;
%if &mac1 = YES %then %do;
data _NULL_;
call execute(<libname statement 1>);
run;
%end;
%if &mac2 = YES %then %do;
data _NULL_;
call execute(<libname statement 2>);
run;
%end;
%if &mac3 = YES %then %do;
data _NULL_;
call execute(<libname statement 3>);
run;
%end;
%if &mac4 = YES %then %do;
data _NULL_;
call execute(<libname statement 4>);
run;
%end;
%mend assign_libname;
%assign_libname;

my guess is libname in open code is compile time statement and hence you see the behavior.

[MrsC]

CALL EXECUTE! Of course! Thank you so much.

[smantha]

I find @Reeza  Solution much elegant than what I provided.

[Reeza]

Use the libname function. 

data _null_;

if "&mac1" = "Y" then libname(name, path);
if "&mac2" = "Y" then libname(......);
if "&mac3" = "Y" then libname(......);
if "&mac4" = "Y" then libname(......);

run;

---

@MrsC wrote:

Is there a way to conditionally assign a library?  I have an EG project (egp file) with a prompt, and I want the user to pick which of 4 databases they want to connect to.  If they pick 2, then I only want to invoke the libname statements for the 2 they selected.  I have 4 macro variables that indicate whether they want the library assigned or not.

It is not working to put the libname statement in a select or an if-then-else because it gets invoked regardless.

---

[smantha]

did not think of libname function.

[Reeza]

I likely have the benefit of seeing this problem before 🙂