[Gambas-user] import mysql dump EXEC or SHELL?

[Ron_1st]

On Wednesday 17 December 2008, Doriano Blengino wrote:
> Ron_1st ha scritto:

----8<----

> >>     
> > When I do understand it correct the error in the line
> >   
> >>>   EXEC ["mysql", sUser, sPassword, sHost, sDatabase, sImport, sSqlFile ]
> >>>       
> > is the missing path for "mysql" (?)
> >   
> Pardon me. I got confused about the exec system call.
> I went to read the documentation, and made a simple test. EXEC finds the 
> normal executables, in some way; so this is not the problem.
OK

> 
> Your problem is that you can not do redirection using "<". It is the 
> shell /bin/sh that does that; if you use such character in an EXEC 
> statement, all you obtain is to pass the "<" character to the command 
> you are invoking which, 99% of the times, will interpret it as a file 
> name or part of it.
> 
> You can do what you want do by this:
> 
>     dim sql_result as string
>     SHELL "mysql -u user01 -p pwd01 ...  < " & Application.Path &/ 
> "mytables.sql" TO sql_result
> 
> The "to sql_result" implies that the command is fully executed before 
> returning, and you can analyze the string to look for errors and such.
> To use EXEC instead, you shoud do:
> 
>   EXEC ["/bin/sh", "-c", "mysql -u user01 -p pwd01 ...  < " & 
> Application.Path &/ "mytables.sql"] to sql_result
> 
> (As you see, it simply calls /bin/sh passing it a command to execute. 
> IE, this is the same as SHELL!)
> 
> You can avoid to call "/bin/sh" if you don't need /bin/sh functionalities.
> 
> Another, more controlled way, but more complicated, is to create the 
> pipes yourself, and do what the shell would do.
> 
> SHELL ... FOR INPUT OUTPUT ...
> 
> This way, you can feed the command whatever you want, not just a file 
> but live data you create on the fly, perhaps reading them from a file 
> you opened... but this is another matter.

Thanks for the lesson, now I understand the difference between
EXEC and SHELL a lot more. 

> 
> Regards,
> 
> -- 
> Doriano Blengino

> "Listen twice before you speak.
> This is why we have two ears, but only one mouth."

Best regards
Ron_1st

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