Oracle's CONNECT BY

[brianlange]

Does Oracles CONNECT BY work by issuing a loop?

 

I am trying to understanding the following query

 SELECT TRIM(SUBSTR(txt, INSTR(txt, ',', 1, level) + 1, INSTR(txt, ',', 1, level+1) - INSTR(txt, ',', 1, level) -1)) as token, level 
            FROM (SELECT ','||:arg1||',' txt FROM dual) CONNECT BY  <= length(:arg1) - length(replace(:arg1,',',''))+1 )  

 

 

If arg1 is a comma delimited list there will be returned a record set with the number of records equal to the items in the command delimited list.

Can someone explain in simple terms what connect by does?