Reading Multiple SAP ASE Tables

SAS opens multiple SAP ASE tables for simultaneous reading in these situations:

• When you are using PROC COMPARE. Here is an example:

  proc compare base=syb.data1 compare=syb.data2; 

• When you are running an SCL program that reads from more than one SAP ASE table simultaneously.
• When you are joining SAP ASE tables in SAS—namely, when implicit pass-through is not used (DIRECT_SQL=NO). Here are four examples:

  proc sql ;
     select * from syb.table1, syb.table2 where table1.x=table2.x;
  
  proc sql;
     select * from syb.table1 where table1.x = (select x from syb.table2
     where y = 33);
  
  proc sql;
     select empname from syb.employee where empyears > all (select empyears
     from syb.employee where emptitle = 'salesrep');
  proc sql ;
     create view myview as
        select * from employee where empyears > all (select empyears from
        syb.employee where emptitle = 'salesrep');
  quit;
  
  proc print data=myview;
  run;

To read two or more SAP ASE tables simultaneously, you must specify either the LIBNAME option CONNECTION=UNIQUE or the LIBNAME option READLOCK_TYPE=PAGE. Because READLOCK_TYPE=PAGE can degrade performance, it is generally recommended that you use CONNECTION=UNIQUE (unless there is a concern about the number of connections that are opened on the database).