SQLPlus is trying to drop package twice

Question

While executing scripts in SQLPlus I've encountered a problem:

script.sql contains the following lines

@some_pkg.pks
@some_pkg.pkb

drop package some_pkg;
/

After calling

> sqlplus user/password@dbname @script.sql

the following messages are in console:

Package created.
Package body created.
Package dropped.

drop package some_pkg;
*
ERROR at line 1:
ORA-04043: object SOME_PKG does not exist

Please, explain what's happening here. Looks like the package is being dropped twice. Is it possible to avoid the error?

Answer 1

The rules of SQLplus command execution basically are:

• Execute the current text when you encounter a semi-colon. Thus if a line doesn't end with a semi-colon, the current text continues to be collected.
• If you encounter DECLARE or BEGIN, collect all the text and do not execute on semi-colons
• If you encounter a slash (/), execute the collected text.

So what happens in your cases is, that both the semi-colon and the slash execute the DROP statements.

To fix it, remove the slash.

You only need the slash if you have a block of PL/SQL, which always with an END statement. Use semicolons for everything else.

Note: the above rules are simplified. It's more complex in practice.

Answer 2

Some examples will help to understand rules:

1. Below code will be executed once

begin
  dbms_output.put_line('executed');
end;
/

2. Below code will not execute (missing semicolon)

begin
  dbms_output.put_line('executed')
end
/

3. Below code will be executed twice

begin
  dbms_output.put_line('executed');
end;
/
/

4. Below code will be executed once

select 1 from dual
/

5. Below code will be executed once

select 1 from dual;

6. Below code will be executed twice

select 1 from dual;
/