书上的例子，下面是程序，为什么总是提示逻辑库“perm"不存在，急啊.......
LIBNAME perm 'C:\users\xxr\MySASLib';
DATA perm.patientmaster;
INFILE 'C:\users\xxr\da.dat';
INPUT Account LastName $ 8-16 Address $ 17-34
BirthDate MMDDYY10. Sex $ InsCode $ 48-50 @52 LastUpdate MMDDYY10.;
RUN;
LIBNAME perm 'c:\users\xxr\MySASLib';
DATA transactions;
INFILE 'C:\users\xxr\daa.dat';
INPUT Account LastName $ 8-16 Address $ 17-34 BirthDate MMDDYY10.
Sex $ InsCode $ 48-50 @52 LastUpdate MMDDYY10.;
PROC SORT DATA = transactions;
BY Account;
RUN;
* Update patient data with transactions;
DATA perm.patientmaster;
UPDATE perm.patientmaster transactions;
BY Account;
PROC PRINT DATA = perm.patientmaster;
FORMAT BirthDate LastUpdate MMDDYY10.;
TITLE 'Admissions Data';
RUN;