System.Diagnostics.Process.Start

[cpopham]

I am trying to use a process start to do a mysql dump. The -u and -p are swicthes that tell the executable what to do. I see the dos window open and close and no errors, but the dump file c:\test.sql is not created.

 

System.Diagnostics.Process.Start("C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqldump.exe", "-u root -pchecli02 myacct > c:\test23.sql")

 

Any ideas?

 

Thanks

Chester

[Joe Mamma]

ProcessStartInfo ps = new ProcessStartInfo(@"C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqldump.exe",@"-u root -pchecli02 myacct");
ps.UseShellExecute = false;
ps.RedirectStandardOutput = true;
Process p=new Process();
p.StartInfo = ps;
p.Start();
using (System.IO.StreamWriter sw = new System.IO.StreamWriter(@"c:\test23.sql"))
sw.Write(p.StandardOutput.ReadToEnd());
p.WaitForExit();

[cpopham]

Thanks Joe Mamma,

 

That did the trick.....

 

Why do you have to use a streamwriter though for the output?

 

Thanks, Chester

[cpopham]

Now how can I reverse this process to read the file backup? I have tried the following code without success:

 

       ps.UseShellExecute = False
       ps.RedirectStandardOutput = True
       Dim p As Process
       p = New Process
       p.StartInfo = ps
       p.Start()
       Dim sw As New System.IO.StreamReader("C:\testNew.sql")
       sw.Read(p.StandardInput)
       p.WaitForExit()

 

Thank You..

 

Chester

[Joe Mamma]

first. . . the streamwriter worked? I just hacked that out of the MSDN help.

 

the reason your first example failed is that the

 

" > testNew.sql "

 

part of the command line are not arguments but output redirection.

 

Now what to you mean reverse? Can you post the command line you want to emulate including any I/O redirections?

Edited July 23, 2005 by Joe Mamma

[Joe Mamma]

and answering your question. . .

 

wouldnt the reverse actually be:

 

Dim sw As New System.IO.StreamReader("C:\testNew.sql")

p.StandardInput.Write(sw.ReadToEnd())

 

StandardOutput is a streamreader - only has read methods

StandardInput is a streamwriter - has write methods.

 

Conceptually you want to Write from a file to the process' StandardInput and Read the process' StandardOutput into a file.

 

make sense?

[Joe Mamma]

oh yeah - In VB.NOT remember to close your stream readers/writers to free resources.

 

In C# I wrap in a using statement to automatically close.

[cpopham]

What my overall goal is is to use the builtin mysqldump application to backup a mysql database and then should something happen, I want to be able to restore from the backup that was generated. Yes your sample worked very well.

 

I tried using the streamreader to reverse the process. Using mysqldump, You would use a statement like:

 

mysqldump -u myuser -pmypassword mydatabasetorestoreto < mybackup.sql

 

The only difference in the statements in mysql is the greater than or less than sign..

 

Thanks, Chester

[Joe Mamma]

then I think it is:

[color=black]dim ps = as ProcessStartInfo = new ProcessStartInfo(@"C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqldump.exemysqldump -u myuser -pmypassword mydatabasetorestoreto")[/color]
ps.UseShellExecute = False
ps.RedirectStandardOutput = True
Dim p As Process
p = New Process
p.StartInfo = ps
p.Start()
Dim sr As New System.IO.StreamReader("C:\testNew.sql")
p.StandardInput.Write(sr.ReadToEnd())
p.WaitForExit()
' remember to close your streamreader
sr.Close()

 

again. . . I am thinking that will work. let me know!

[cpopham]

I am getting the error that says:

 

StandardIn has not benn redirected

 

Chester

[Joe Mamma]

oops!!!

[color=black]dim ps = as ProcessStartInfo = new ProcessStartInfo(@"C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqldump.exemysqldump -u myuser -pmypassword mydatabasetorestoreto")[/color]
ps.UseShellExecute = False
[b]ps.RedirectStandardInput = True[/b]
Dim p As Process
p = New Process
p.StartInfo = ps
p.Start()
Dim sr As New System.IO.StreamReader("C:\testNew.sql")
p.StandardInput.Write(sr.ReadToEnd())
p.WaitForExit()
' remember to close your streamreader
sr.Close()