insert or update errors

Is there a way I can stop a form from inserting or updating a record when there is an error. I have an sql 2000 DB. I have noticed that if the db field can handle 50 characters and the form field has no limit on the number of characters no errors are displayed to the user if they try to use more than the 50 characters in the textbox. The record is not saved. None of the fields are saved. I do notice the autonumber generated is skipped by the db. That is, the next autonumber for a successful insert skips the logical next number. How do I capture this error, or any save error and return the user back to the form? Yes, I have limited the number of characters a user can type on the textbox now, but I would really like to catch save or insert errors. I use asp.net 2.0 and VB. I don't know C#.
thanks
Milton

You can add some validation within stored procedures but are just using raw SQL for insert and update? It is far better to use stored procedures for all insert, update and delete operations. (If possible all access should be via stored procedures)

If you include an output BIT parameter called say NAD (for No Abnormalities Detected) and only set to to 1 if the insert/update worked with no error. Use a command button to fire the insert/update and if there is an error, post a message to the user and stay on the same page.

|||Its always a good idea to do some basic validation at the front end (like data types, length etc) before passing all the data to the db and validate at the back end. Validation at the DB level should be for any constraint validation, PK-FK validation etc.|||

Is there an example here or elsewhere? I don't see how the form interacts with the sql server. Output BIT parameter? I have a linkbutton control on my form which has no code behind. I have the command name as "insert" for that link button in the properties of the linkbutton. I use VB not C#.
thanks
Milton

|||I will post some links for you tonight.|||Please look at my posting onhttp://forums.asp.net/thread/1687128.aspx. This will allow you to create a range of stored procedures plus wrapper code in either VB.NET or C#. The accompanying library is in C#. I will attempt to produce a VB.Net port this weekend.