SubscribeWhy? In most of the code I have been working on lately it seems like the developer was afraid of exceptions. Now a lot of this code is 1-3 years old and written by VB developers in VB.NET. (I’m not trying to bash VB here. I believe good code can be written in any language.) I have heard a few arguments against exceptions which I agree with under certain circumstances.
- Exceptions should not be used in normal program logic. Certainly if you are writing a loop and could throw and then catch a few thousand exceptions this is true, but if there is an error in the code or data then I think an exception is appropriate. I try to check my public function parameters and throw ArgumentException or ArgumentNullExceptions.
- Exceptions are slow. Slow is a relative word. Especially when programming. Again if an exception will be thrown and caught several times during normal program execution that isn’t good. However if you throw an exception when invalid data comes back from the database or when a webservice isn’t responding then it is not slow at all.
I have heard both of these used as excuses not to ever throw an exception. That they just aren’t a valid option under any circumstances. There are some places where I feel exceptions are useful:
- Invalid input: the program shouldn’t crash if the user puts text in an integer input, but if that text makes it down to the lower levels of code where it shouldn’t be. In either case the user should be presented with an error message.
- “Impossible” states: as a sanity check. What if some one mucked up the database, or if some files were accidentally deleted.
- Corrupt data/connectivity issues: when the database is down for example
I’m just sick of stored procedures that return a 0 on an error, then the function checks for 0 and returns -1, then the page checks for -1 and makes a label visible, etc. It’s just so f’ing confusing when code at so many different layers has to check for the error code and pass an error up the stack. I also find exceptions much easier to debug (unless they are caught and silently discarded, but that’s another post).
Guess I just needed to vent a little…
Hi,
That was a very good article. In regards to exception where I am stuck is..
I have an application that runs on sql server with 5-6 client machine. I have two tables in my database.
Say a customer has deposited Rs. 500 to his account, this entry is recorded in his unique account in TableTransaction.
In the TableMaster, his account is updated.
Say his balance was Rs. 200, he made a deposit of Rs. 500, so the TableMaster is updated by Rs. 700.
First the TableTransaction sql inserts and than TableMaster sql updates and they are binded through a commit.
Say one out of thousand entry, my TableMaster field is not getting updated. The balance of the particualar customer remains Rs. 200 only thus creating a dispute.
Its not throwing any exception also thus stopping the rollback of the transaction. Is it possible that a row doesnt get updated and doesnt throws any exception also??? I am in a fix.
This is my process of transaction
‘Connection Opens—–
con = connect()
con.Open()
‘transaction begins here——-
trans = con.BeginTransaction()
Try
‘Data is inserted into Table Transaction———
cmd = New SqlClient.SqlCommand(“INSERT INTO TableTransaction……..”, con, trans)
cmd.ExecuteNonQuery()
‘Data is updated in Table Master———–
cmd = New SqlClient.SqlCommand(“update tablemaster set……….”, con, trans)
cmd.ExecuteNonQuery()
‘Data commited——–
trans.Commit()
Catch ex As Exception
trans.Rollback()
MsgBox(“Bill could not be generated, Please try again.”)
End Try
con.Close()
Am not able to diagonise where the error is taking place. Please help. I really want to know why this error is taking place.