right mysql syntax to use (1 reply)

Hi , l have 3 questions .

1- how to get a table depth l mean how many rows a table has
2-l am trying to make a log in windwos what is the right syntax to check in all
rows of only one column which l want to use to verify.
3- l am using vb .net and l dont understand what is the meaning of using
while read. reader() ....

end while

what while means ?

code :

While reader.Read()
id.Text = reader.GetString(0) ' OJO EL TEXT DEBE COINCIDIR CON LA DATA DE LA TABLA
abrev.Text = reader.GetString(1) ' OJO EL TEXT DEBE COINCIDIR CON LA DATA DE LA TABLA
num.Text = reader.GetString(2) ' OJO EL TEXT DEBE COINCIDIR CON LA DATA DE LA TABLA
nom.Text = reader.GetString(3) ' OJO EL TEXT DEBE COINCIDIR CON LA DATA DE LA TABLA

End While


Thnaks .