how can i write delete query in matlab

i try but it dos not work elete(conn, 'schduale', colnames1)

Answer 1

[Oleg Komarov]

EDIT

Use:

curs = exec(conn,'delete query')

where delete query is one of the expression as indicated here http://www.w3schools.com/sql/sql_delete.asp

check if you queried correctly with:

curs.message

[sayer ali]

i try this

exec(conn,'DELETE FROM schduale')

exec(conn,'DELETE * FROM schduale')

but dos not work

[Oleg Komarov]

What do you mean does not work, error message, unexpected result?

[Oleg Komarov]

There's no delete all, unless all is a column

[David Goldsmith]

I too was finding that this didn't work, and worse: it was "hard-locking" the DB such that I had to exit MATLAB in order to be able to access the DB again, even from w/in MATLAB! However, that was the clue, having remembered similar problems in the past, that eventually led me to the solution: chances are, sayer, (and anyone else who finds this 'cause you're having the same problem) that your DB has autocommit turned off (as it should be), so DB change operations (as opposed to merely query operations) needed to be committed before they "take," i.e., after your exec(conn, 'DELETE FROM table WHERE ...'), you must run commit(conn). So, for careful execution, I recommend code something like this:

curs = exec(conn, deleteStatement);

if isempty(curs.Message)

commit(conn)

:

else

rollback(conn)

:

end

close(curs)

Note that after any DB change operation (i.e., including update and fast/insert) you must call either commit or rollback to remove MATLAB's lock on the DB.

HTH,

DG

Answer 2

[sayer ali]

exec(conn,'DELETE all FROM schduale')

[Oleg Komarov]

See edit and my comments