In my MVC 3 project (for a company that give lessons), I have about 100 clients in a database and the amount they pay per month is constant - it's either R640 or R460, depending on whether they're enrolled for a group or a private lesson. What I want to do is, have one button that when clicked, will generate database entries for invoices for each client for the current month - so will generate 100 invoices. Would this be difficult to do?
Not really.
you would have your button link to a controller action maybe called GenerateInvoices?
Then loop through each client and do the checks and the database writings you need done.
Just write the code and have the buttons action be the controller action.
Related
I have a conceptual problem.
For an ASP.NET MVC / C# website (although the exact technology may not be that important) I have 2 linked drop downs (html select) with Countries and Cities of a continent.
These are currently kept in 2 database tables and as you imagine the Cities table has round 10 000 records.
The current functionality is:
- initially the country select is populated.
- the user selects a country, an ajax request goes to the server, retrieves the cities for that country_id and populates the second (cities) select.
Sometimes it gets a bit slow as you might imagine, and since these are in the end static values (the lists will not change) what will be the best way to treat this situation?
I would recommend implementing it, using the jquery chosen plugin Chosen
plugin that can be used to filter, results, but since you are getting such a big response you can incorporate a search filter functionality with ajax as shown here, Jquery Ajax-Chosen
Hello and thanks for reading this, could really use some help ;)
On my site, you play a puzzle after you entered your information and when you either complete the game before the time runs out or not your score will be posted into the gridview below.
I cant post a image but you can check the site if you want a good view about what I'm talking about Website
everything is working right now. you can play it and as you can see the time is showed. in the database that the information is stored in you every row has a unique ID.
here is my question - when someone hits "start spillet" and adds the information to the database, how can i get the unique ID that when that just been created and store it into a session so i can use it later.
(here is a row from my Database)
ID NAME EMAIL COLLEGE CLASS/TEAM TIME
114 Carsten TESTUSER#mediacollege.dk Technology h0dt100413 54
public string generateID()
{
return Guid.NewGuid().ToString("N");
}
using this function you will get a unique id and you can user it as session.
it will different every time
We have a set of catch all search pages we're creating in our ASP.NET application. We have an initial search page, a SERP, and then a single item details page. All 3 pages have a search bar with initial criteria, more criteria, and advanced criteria choices.
When we put all of our criteria together, in addition to the main search box we have 20 different criteria parameters (from price, to price, sale item, date created, etc.) and then three collections of parameter IDs. These collections are from a list of the Manufacturers, Product Lines, and Categories our users can search from. So we have this fixed set of 20 fields and then 3 collections that could have a manufacturer or two, or could hold a collection of 100 Guids for the lines whose checkboxes they selected and want to search through.
In our old system we had a single form solution and we just posted back and submitted everything to our business object, passing it into a method that returned the results. In this new form we need to submit the results from page to page and persist this criteria. We're trying to figure out the best way to persist the data, when I say best I mean most efficient.
Querystring - This isn't going to work with large collections of Guid values for the 3 collections.
Session - We would create a criteria object and store it in the Session. As they move from page to page we can pull it out. At our peak we probable have 200-300 people using the server concurrently and the search is our most used form. I'm worried about performance with all those session variables.
Database - We were thinking of serializing and stashing this criteria object into the database (SQL Server 2k5) and the users would always have a current Search or last Search in the database. This eliminates some of the web server load from the Session solution but I'm worried this object load, serialization, db round trip, and unload is going to slow the forms down and affect user experience.
I'm looking for advice on which method is going to work most efficiently for us or if there is an accepted best practice or pattern I've overlooked.
With HTML5 you can use localStorage and sessionStorage, which makes the client keep the information in their browser.
http://www.w3schools.com/html/html5_webstorage.asp
I'm trying to accomplish something like a facebook news feed wall, loading N number of results from the overall dataset, starting with the most recent, date descending. When you click “more”, it displays the next N underneath and so on until you finish the dataset.
I’m struggling to come up with the best design to accomplish this. Ive always been told that stateless web services are the only way to build a scalable enterprise application, which means that as I understand it, keeping the whole results object cached serverside on the first call to the page, and just taking N results from it with each subsequent web service call is a no no?
If that’s the case, then something like GetResults(int pageindex, int pagesize) would work.... and thats how I WAS going to do it but then I realised it would not work if someone added a new DB record in between calls. Eg you start with 23 wall feed items in the DB and want to display them 10 at a time.
First call, page 1, page size 10 will return results 14-23 (most recent first)
Someone then adds 2 new posts, so you have 25 now in the DB
Second call, page 2, page size 10 will return results 6-15, two of which were already returned in the first call.
So this offsetting approach doesn’t work because you can’t guarantee the underlying dataset will remain the same between calls.
Im confused, how do I accomplish this?
Edit: Sorry a little more info. To avoid the problem of huge data table lookups, I had considered the option of pre-populating a "transient" table with the last few days data for that user when you first load the screen, then just reading the results a page at a time from that transient table to make it faster reading, with a slightly slower load time. Then when you exhaust that data, you bring in the next period (say 2 weeks) into the transient table and continue reading.
The difficulty is that users will "Post" items which then automatically will be picked up by users who match their search criteria. Eg if your criteria state you want to meet people between 25 and 32 and within 50 miles of you, then when you load up your news feed, you want it to show posts from all users who match your criteria. Kindof like a dynamic friends list.
How I was going to achieve this was at time of login, a stored proc would run which would populate a transient table in the DB by selecting all users and filtering down based on age and location criteria which I have in static lookup tables (postcode distances etc), then it will save the list of Users who match your criteria to this transient table for use whenever you then need to filter posts or search users. If you update your preferences, it will also recalculate this but only when you update prefs or re-login. So any new users signing up won't appear until you next login, which is fine I think.
Then when it comes time to display your news feed, all it does is retrieves this list of User Ids from the DB who match your criteria, then brings back all NewsFeedPosts which were posted by those users. Hey presto, dynamic news feed!
But obviously this is a subset of the entire NewsFeedPost table which is generated on the fly, so it doesn't make sense to recalculate this every time a user clicks "more", so this was how I was thinking about implementing it.
Tables - NewsFeedCurrent, NewsFeedRecent, NewsFeedArchive
New posts are created in the current table. Every night a batch job runs that moves all data from current that is 2 days old, to the recent table, and any data in the recent table that is a week old to the archive table.
The thinking being that 90% of the time, the user will only be interested in the last 2 days of data. So keep table small for access time. Another 9% of the time the user may want the last weeks data. So keep that separate in a secondary table. Then only 1% of the time the user wants data more than a week old so keep that in a larger, slow archive table that will be slower, but gives you performance boost by keeping current and recent tables small.
So when you first hit the news feed page, what it was going to do is take the pre-generated user list for your account and pull out all NewsFeedCurrent items and put them in a transient table, say TempNewsFeed under your user ID. You can then work with this resultset just by pulling back everything for your user id, no filtering required for items you arent interested in as they are pre-filtered. this will add a second or so to the page load but will improve response time when fetching results. Then when that data is exhausted, it will then - again using the list of users matching your criteria - pull out all relevant data from the Recent table, adding it to the TempNewsFeed table, allowing you to continue fetching data up to a week old. When thats exhausted, it will finally go to the archive table and using the user id list, pull out all data matching this and put in the temp table, allowing you to continue navigating the remaining data. This will give a fairly significant delay as it populates the archive data but if you are going back a week, then you will have to accept 5-10 seconds wait while it populates the data and says "loading data...". Once it has though, navigating historical data will be just as quick as recent data as it will all be in the transient table.
If you refresh the screen or go back onto it from another screen, it clears out the transient table and starts again from the Current table data.
Hope my answer makes sense, makes the right assumptions ...
I would divide the news feed into two sections. The first is for incoming news - which would be powered with AJAX calls. It is constantly saying "What is new?" The second section is for older news, where the user can lazily load more news by scrolling down.
Newest News Items
The important point is to make note of the maximum news feed id on your page. Let's imagine that is 10000. When the user loaded the page, news feed id 10000 was the latest news item.
When the new section is updated with AJAX, we simply ask, "What is newer than id 10000?" and we load those items onto the page. After we load them, we also increment the id on the page. For example, if we start with id 10000 and we load five new news items, the new id would be 10005. The next call would ask, "What is newer than 10005?"
Older News Items
The older section would keep track of the oldest news item on the page. Let's imagine they scroll back for a weeks worth of news. The minimum news item id would be 9000. When they want to scroll back further, we simply ask, "What is older than 9000?"
The idea then is to maintain on the page the maximum news item id and the minimum news item id and then keep loading from that reference point.
I have an operation (That I can't change) that starts threads that make calls to our Oracle database to see if a certain hotel(s) has availability on a certain date.
If a date/hotel combination has availability, that thread returns information about the date/hotel in the form of a DataTable that is merged into a Main DataTable of results. Yes, I know ... I inherited this.
So I am trying to re-write this operation. I still must query Oracle in threads to get the availability information, but I want to display the data as it is returned (in chunks of 5, 10? I'm flexible), instead of having the user sit in front of the screen for up to 4 minutes before a complete result is spat out into a GridView.
How do I do this directly from an .aspx page so I can make a web service call and populate a grid (JqGrid?) with the results?
If I haven't provided enough information or described what I am trying to achieve, please let me know and I will elaborate.
Oracle provides a field on each row called "rowid"
(http://www.adp-gmbh.ch/ora/concepts/rowid.html)
The first time you send the query, send in the int (x) to define what the highest rownumber you want is. Have the service return the total number of rows and the first x rows.
Then, the 2nd time you send the query, get the next x rows, rinse and repeat.
Basically, you need to send an ajax query for rows x through y each time until you have them all loaded.
I would recommend paging as well, since users typically don't want to see hundreds of results at a time.