Oracle中的“批量收集”和“立即执行”

Question

is it possible to execute the "bulk Collect into" with the "execute immediate" commands in oracle? All of that would be part of a function that returns a pipe lined table as a result.

Answer 1

Yes, technically you can:

  1  SQL> declare
  2   type x is table of t.id%type index by pls_integer;
  3   xx x;
  4  begin
  5   execute immediate
  6   'select id from t' bulk collect into xx;
  7   dbms_output.put_line(xx.count);
  8  end;
  9  /
426 

And Oracle clearly states this in the documentation:

http://docs.oracle.com/cd/B19306_01/appdev.102/b14261/executeimmediate_statement.htm

But you can use more useful way event if you really NEED to execute Dynamic SQL - weak ref cursors. You will have the access to such powerful option as LIMIT and will be able to use collections of records.

SQL> declare
  2   type x is table of t%rowtype index by pls_integer;
  3   xx x;
  4   c sys_refcursor;
  5  begin
  6    open c for 'select * from t';
  7    loop
  8      fetch c bulk collect into xx limit 100;
  9      dbms_output.put_line(xx.count);
 10      exit when c%notfound;
 11    end loop;
 12    close c;
 13  end;
 14  /
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26   

Answer 2

Following the idea proposed by Dmitry Nikiforov I solved the problem using cursors and here is the solution ;)

FUNCTION myFunction (  parameter_p IN VARCHAR2) RETURN myTableType PIPELINED

IS
  c sys_refcursor;
  stmt varchar2(4000);  
  out_rec mYrowType;
  rec mYrowType;
BEGIN

    stmt:='Select * from ''' || parameter_p || '''';
    open c for stmt;

    LOOP
    fetch c into rec;
    EXIT WHEN c%NOTFOUND;

        out_rec.field1 := rec.field1;
        out_rec.field2 := rec.field2;
        out_rec.field3 := rec.field3;

        PIPE Row(out_rec);
    END LOOP;

  Close c;
  Return;

END myFunction;