Oct 13

I spend so much time in the same problem ora-12154. The fault is could not resolve the connect identifier specified. I know it is tnsnames.ora related . but after checking the content of  it again and again. I don’t know where the hope is. At last, I ask the mentor and he asked another cooperator Lin. He dealed with it at one minute . He found the location of the tnsname is not in the right place.
We must place it below the  network/admin file 
When I add the Intial catalog= walsinl2, it comes the error :Initial catalog is an invalid connection string attribute.