ADO.NET :: Checking Existence Of A Record In Sql Database Using IF EXIST And Reporting Outcome On Asp Page
Sep 22, 2010
I have a page that inserts a record to an sql database and I would like to do the following:
(i) Check if a record already exist before trying do an insert
(ii) If a record exist, the page should be able to inform/display a message in a textbox informing the user that the record already exist.
I have seen a number of post on the internet that suggest that one possible solution is to write a sproc and use the T-sql IF EXIST function. However, I have NOT seen a complete code showing (a) how this can be done (b) how to call the sproc from an asp page (c) and MORE IMPORTANTLY how to display a message informing a user that a record already exist i.e. when the record already exist in the database.
As an extensibility option for my web application I would like to allow the user to add sections to it by simply making new folders and uploading files to them. So, for instance, if they created (in the webroot): /UserContent/StaticPages/First/Second/index.txt. Then in the main menu there would be a new menu point "First" with the submenu point "Second", which would lead to markdown-parsed version of index.txt. This way the user can upload any static menu points he wants (such as "About us", "Contact us", "Our Mission" etc.) Another extensibility point is that I would like them to add headers/footers to specific webpages in a similar fashion. I'm using ASP.NET MVC3, so there are pretty URLs, and it would be easy for the user to just create: /UserContent/Additions/Store/Categories/35/header.txt
And when someone opened [URL] the markdown-parsed header.txt would be prepended. This is simple for the user, and simple for me (I don't need to make sophisticated admin panels and WYSIWYG editors). However I'm worried about the performance. This scheme means that on each GET request I would need to scan the /UserContent/StaticPages folder and check for the existences of the header/footer files (several, because parent levels can have their header.txt/footer.txt as well).
I could cache the result, but then I have to manage the cache and the user will need to know that changes can take up to X minutes to display. Would this be a premature optimization? There won't be much data in those folders, so Windows will probably be able to easily cache their contents itself.
Before a subscription to a newsletter and the record will be inserted, i'd like to check if the record already exist ina sql-server database. This what i've got as dusfar
adres = TxtEmail.Text DBConn.Open() If adres <> "" Then Try DBCmd = New SqlCommand("SELECT COUNT(*) FROM TBL_Subscribers WHERE email = @adres)", DBConn) ''Add DBCmd.Parameters.Add("@Email", SqlDbType.NVarChar).Value = adres DBCmd.ExecuteScalar() DBAdap = New SqlDataAdapter("SELECT * FROM TBL_Subscribers ORDER BY ActivateDate", DBConn) DBAdap.Fill(DS) Catch exp As Exception Response.Write(exp) End Try End if
I am using a form to add and edit record of database.
In Add case my email box has no value. I have used customservervalidation to check the given email address with previous database records.
In Edit case my email box is populated with data from database.
When i click save button in both cases my customservervalidation method invokes and checks the given value. it works fine for new/add case but in edit case it checks with itself also and says duplicate email... pointing own record...
I have an ASP.NET page which contains a large number of gridviews, which contain masses amount of data which take a fair while to rebind. I currently have it set so the gridviews are only bound when the account number is changed (on the page, the user searches for an account which then displays their information). I'd like it to be able to monitor a database table (hashing it maybe?) every few minutes, then if there are changes spawn a popup box informing them, and an option to have the gridviews refreshed. Firstly, is this possible in ASP.NET/C#? Secondly, what would the performance impact be on the page checking the hash/checking for changes in a large DB table?
I'm looking to find out the most efficient pseudo-code in order to achieve the following conditions:
I have an "event" which has a start and an end date (S1, S2). I am try to find out if this even occurs within a specific timeframe (D1, D2). If the event only lasts for one day, it will not have an end date. I only want one occurance of the event in the query.
If anybody is able to assist with tbe psuedo code behind such a query, I'd be grateful.
when click save button,I want to save the textbox values to database table..If the record is already available then just update that value... I have the code for insert and update..but i don't know how to check the already existing record..I need ,check existing record using only auto generated id
I'm having trouble with an SQL statement. I want to have one statement that checks to see if it a record exists. If it does, then update it and if it doesnt then insert a new one in the server. Here is what I have so far:
I have a table "assignments" with records that are assigned to multiple "users" by the "department" they belong to. Each user then can have it's own "status" for each assignment.
When the user logs-in i need to show all his assignments and the status.(but status record doesn't exist yet)
When a new assignment is created I don't want to have to create a new record relating the assignment to the user. I want the relationship to be by the department the user belongs to and the department the assignment was assigned to.
Only thing i can think of is when the user logs in to load the assignments that belong to the user's department then look thru all the records. For each record loop thru the status table. If a record exist show the the status. if it doesn't then make default value and when the users clicks to view the assignment a new status record will be added.
Only thing i don't like is looping thru the status records while looping thru all the assignments.
How else can I do it? I don't see how could join the assignments table and the status table if the status record doesn't exist yet.
tables: [ASSIGNMENTS] assignmentID departmentID assignment [DEPARTMENT] departmentID department [USERS] userID departmentID user [STATUS] userID assignemntID status
I have one div in my page i want show my store information in that div from DB
Name:Itally mall
Address:Italy
Tel:123456879
Description:test test test
It is just one time per page how i can do it?I know that i can use gridview,datalist but here i just need read my data just 1 time from DB i dont want repeat it so what can i do?
I am counting from a table for that i have written code as below
protected void get_Id_Afterpoint() { int counter = 0; string strSql = "select count(*) as ID from tblEnergy where ID=?"; OdbcCommand com = new OdbcCommand(strSql, con); com.Parameters.AddWithValue("ID", DropDownList1.SelectedValue); OdbcDataAdapter oda = new OdbcDataAdapter(com); DataTable dt = new DataTable(); oda.Fill(dt); if (dt.Rows.Count == 0) { lblID2.Text = "1"; } else { counter = dt.Rows.Count; counter = counter + 1; lblID2.Text = Convert.ToString(counter); } }
there is no record related to DropDownList1.SelectedValue. but as i am counting if(dt.rows.count) and i put break point on the bolded part it shows 1 record. how it can be possible?
I've done this successfully before, but now i'm scratching my head trying to figure out why i'm only getting the 1st record this time. i've debugged the code and verified that the datasource is returning 300+ records, however the report viewer only shows 1 page and the Next button is disabled.
I am building next version of our Asp.net web application. for this new build one column is added in database. Now I have to make this new build backward compatible. Means build should be good for old database design (without that added column) and new design. Just wondering if there is an efficient way to know whether or not particular column exists in table you are working with?
at this time, I am getting all the columns in datatable and loop through it to make sure that new column is available in it? if yes the modified query with this column and if not then old query. Just cuious, what is the best industry practise to make any build backward compatible with old database design?
I am using paging to my gridview (pagesize=4) . now i am in (X) page and i want to get (X+1) page top record or (X-1)page bottom record , how i can get .
I am creating a report using sql reporting services (.rdlc) in asp.net web application. I am displaying master records using List because I need to display one record in one page. In each page now I want to display the child records in a table inside the same List control.
For example: In mater records there will be Department Name, Department Location, Department Zip. In child records there will be Employee Name, Employee Id, Employee Salary, Employee Start Date. There is a link between Dapartment and Employee table by Department Id. I want to display one department record in one page and the all employee of that department in same page in a table. And next page of the report will have other department record and respective employees in a table.
I am being able to display Department records in each page but not being able to display Employees records in a table for particular Department Id. For this I used List control.
I have a literal control within a ContentPlaceHolder on my master page. In the master page code behind, I want to check to see if the literal is still there and if so, update the text.
This is my code, but it always believes my literal control does not exist:
I have a website which loads images from a CDN. I have a requirement to check for the existence of 100s of images on the CDN.
I am using this code to achieve this:
Protected Function RemoteImageExists(ByVal Path As String) As Boolean Dim httpRequest As HttpWebRequest = CType(WebRequest.Create(Path), HttpWebRequest) httpRequest.Method = "HEAD" Try Dim httpResponse As HttpWebResponse = CType(httpRequest.GetResponse, HttpWebResponse) Catch ex As Exception Return False 'Undesirable flow, but seems unavoidable :( End Try Return True End Function
This is still very slow, and many requests timeout. Is there a faster way to do this?
how to check if a particular data in the database already, for example, i want to check if a username already exist in database, then the user cant choose that username.
I would like to design master page header to show report title and date. For Master footer page, I want to show address and page number. Thus, all report no need to design more page header and footer.
How to check wether username exist in database or not in my regestration page? and plus i want to implement this feature also...suppose i allowed one user to select username as 'user01' and that user is still completing his form and same time another user tries to check whether 'user01' exist in database or not then i should show user as that 'user01' is not available for him and he should try to select some other username for him...
