Javascript update database asp

Ask a question. Quick access. Search related threads. Remove From My Forums. Answered by:. Archived Forums. Sign in to vote. User posted Hello, I would like to be able to display a confirmation popup, prompting the user to confirm or cancel, whenever the user updates a gridvew, and that update conflicts with other database entries. The comment is now awaiting moderation. You will be notified via email when the author replies to your comment. Please select a comment to reply. You can add your comment about this article using the form below.

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All the code samples and API provided by the authors are solely their creation and neither the author nor the site are responsible if it does not work as intended. I agree to the above terms. Download Required. As we said when we introduced if blocks, sometimes you want to run alternative code if the condition you're testing isn't true.

That's the case here. If the condition passes that is, if the ID passed to the page is ok , you read a row from the database. However, if the condition doesn't pass, the else block runs and the code sets an error message. The code uses Request. QueryString["id"] to get the ID that's passed to the page. The code makes sure that a value was actually passed for the ID. If no value was passed, the code sets a validation error. This code shows a different way to validate information.

In the previous tutorial, you worked with the Validation helper. You registered fields to validate, and ASP. NET automatically did the validation and displayed errors by using Html. ValidationMessage and Html. In this case, however, you're not really validating user input.

Instead, you're validating a value that was passed to the page from elsewhere. The Validation helper doesn't do that for you. Therefore, you check the value yourself, by testing it with if! If there's a problem, you can display the error by using Html. ValidationSummary , as you did with the Validation helper.

To do that, you call Validation. AddFormError and pass it a message to display. AddFormError is a built-in method that lets you define custom messages that tie in with the validation system you're already familiar with. Later in this tutorial we'll talk about how to make this validation process a little more robust.

After making sure that there's an ID for the movie, the code reads the database, looking for only a single database item. You probably have noticed the general pattern for database operations: open the database, define a SQL statement, and run the statement. Because the ID is unique, only one record can be returned. The query is performed by using db. QuerySingle not db. Query , as you used for the movie listing , and the code puts the result into the row variable. The name row is arbitrary; you can name the variables anything you like.

The variables initialized at the top are then filled with the movie details so that these values can be displayed in the text boxes. If you'd like to test your page, run the Movies page now and click an Edit link next to any movie.

You'll see the EditMovie page with the details filled in for the movie you selected:. Notice that the URL of the page includes something like? So far you've tested that Edit links in the Movie page work, that your page is reading the ID from the query string, and that the database query to get a single movie record is working.

You can change the movie information, but nothing happens when you click Submit Changes. In the EditMovie. If you're not sure exactly where to put the code, you can look at the complete code listing for the Edit Movie page that appears at the end of this tutorial. Again, this markup and code is similar to the code in AddMovie. The code is in an if IsPost block, because this code runs only when the user clicks the Submit Changes button — that is, when and only when the form has been posted.

IsValid — that is, you're not combining both tests by using AND. In this page, you first determine whether there's a form submission if IsPost , and only then register the fields for validation. Then you can test the validation results if Validation. The flow is slightly different than in the AddMovie. You get the values of the text boxes by using Request.

When the page ran the first time, the code got the ID out of the query string. You get the value from the hidden field to make sure that you're getting the ID of the movie that was originally displayed, in case the query string was somehow altered since then.

The really important difference between the AddMovie code and this code is that in this code you use the SQL Update statement instead of the Insert Into statement. The following example shows the syntax of the SQL Update statement:. You can specify any columns in any order, and you don't necessarily have to update every column during an Update operation.

You cannot update the ID itself, because that would in effect save the record as a new record, and that's not allowed for an Update operation. Important The Where clause with the ID is very important, because that's how the database knows which database record you want to update. If you left off the Where clause, the database would update every record in the database.

In most cases, that would be a disaster. In the code, the values to update are passed to the SQL statement by using placeholders. To repeat what we've said before: for security reasons, only use placeholders to pass values to a SQL statement. After the code uses db. Execute to run the Update statement, it redirects back to the listing page, where you can see the changes. You might have noticed that you use slightly different methods to run different SQL statements.

To run a Select query that potentially returns multiple records, you use the Query method. To run a Select query that you know will return only one database item, you use the QuerySingle method. To run commands that make changes but that don't return database items, you use the Execute method.

You have to have different methods because each of them returns different results, as you saw already in the difference between Query and QuerySingle. The Execute method actually returns a value also — namely, the number of database rows that were affected by the command — but you've been ignoring that so far.

Of course, the Query method might return only one database row. However, ASP. NET always treats the results of the Query method as a collection.

Even if the method returns just one row, you have to extract that single row from the collection. Therefore, in situations where you know you'll get back only one row, it's a bit more convenient to use QuerySingle. There are a few other methods that perform specific types of database operations. You can find a listing of database methods in the ASP. The first time that the page runs, you get the movie ID from the query string so that you can go get that movie from the database. You made sure that there actually was a value to go look for, which you did by using this code:.