drop column using vb

i need help for drop colum from table i wrote the below code but it give ERROR:timeout expire

i have one combobox and one button while selecting combox the selected column will drop by clicking the button

i have more than 29 columns in the table vmbs and all columns have an entry in the combobox
it is working with small tables but it will not work with large tables
what can i do plz reply soon

sub command1_click()

dim db as new adodb.connection

dim rs as new adodb.recordset

str=com1.text

db.open "dsn=jay"

set rs=db.excute("select * from vmbs;")

sql="alter table vmbs drop column [" & str & " ];"

db.excute sql

db.close

end sub

I used to run into this one and the way I solved it was to specify the timeout (in seconds).

On your command1_click() event, try adding the following at the beginning of your event code
(but after you dim db as new adodb.connection):

db.CommandTimeout = 300 'This is a five minute timeout.

I hope this helps, I used it a lot when dealing with a particularly busy SQL server.

-->dear sir i tryed like wise but it is not working after complition of 5 minits it show the same error
and one thing is my server is not that mutch busy it is very few data to access please tell how to solve