Nodes in sap abap program

I have requirement to work with nodes in program with parameters.

so i created on table say ztab with some fields.

i created logical database by se36 say zldb.

now i created node with same name as table ztab. so node contains the fields which i created table.

now iin program i mentioned as nodes ztab.

but getting error as "ztab is not node of logical database_s.

so how to resolve this error? any process in creating nodes to mention them in program?