Use an index on the table with your key values and call "INSERT OR UPDATE INTO t(...) VALUES(...)" for all creation and update operations. Unless you're dealing with a tremendous amount of data per record this will be perfectly efficient.
On 11/28/06, Rich Shepard <[EMAIL PROTECTED]> wrote:
This is a generic approach question, not neccesarily tied to a specific database and certainly not to a particular language. For context, however, my application is written in python and C and uses sqlite3. Here's the situation: A database is created or opened, and the user enters data via fields on a form. These data are then saved by inserting into the appropirate table and fields. Now, if the user goes back to some of the fields and changes the values in them, the table row should be updated, not re-inserted. What is the most efficient approach to test whether a record has a value in a field that's different from the one displayed? The only approach that occurs to me is to retrieve each field from the table and compare values with those in the form when the "Save" button is clicked. If the field is blank, then use an 'insert' statement; if the field has an existing value, use an 'update' statement. Seems kludgy to me. Interestingly, I've not encounted this before with any database application I've written, because they were all done in discrete steps. That is, a menu was used to select whether new data were to be entered, or if existing data were to be modified. With an event-driven GUI engine, and the ability to modify the values in the widgets, it's a brand new game for me. Thanks, Rich -- Richard B. Shepard, Ph.D. | The Environmental Permitting Applied Ecosystem Services, Inc.(TM) | Accelerator <http://www.appl-ecosys.com> Voice: 503-667-4517 Fax: 503-667-8863 ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
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