VWD 2008 Express. Visual Basic.
I know how to create an AccessDataSource on my aspx page and how to use the datasource to populate gridviews, etc. But I want to know how I can programmatically populate a dataset by querying an Access database. How do I make queries to an Access database programmatically?
so I have a web programming assignment for university where I'm building a website that uses an Access database but I have hit a brick wall with something.I'm using parameterized queries to query my database. For one of my queries, I want to be able to take a bunch of parameters that are optional, and if they aren't needed I'll pass in a value of null and I'd like the part of the where clause relevant to them to evaluate to true. This is straightforward in most databases, from my understanding you could do something like to make param1 an optional parameter.
WHERE ((@param1 = ARandomColumnName) OR (@param1 = null))
However this can't be done using Access, as all parameters in a query are represented by a ?. Every ? is assumed to refer to a different parameter, so if you want to use a parameter more than one (like the above code I wrote does) then you'd have to pass it twice. This seems hacky to meSo what do I do? I have spent *hours* googling and banging my head on the desk. I'll cry if I missed something really obvious
I work in an ASP.net/ SQL Server development environment. If my only concern is speed should I go with parametrized queries or should I use an ORM such as nHibernate or LINQ?
View 5 RepliesIs there a way to combine the LINQ queries together and have access to both of the results independently?
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Among methods: static variables, viewstate, session and cache for avoiding on loading repeatedly and less making queries to the database. What do you think the best method of the 4 above? I Think Cache is the best one? Or any other methods better in Asp.net 3.5 or higher?
View 3 RepliesI'm after some thoughts on how people go about calculating database load for the purposes of capacity planning. I haven't put this on Server Fault because the question is related to measuring just the application rather than defining the infrastructure. In this case, it's someone else's job to worry about that bit! I'm aware there are a huge number of variables here but I'm interested in how others go about getting a sense of rough order of magnitude. This is simply a costing exercise early in a project lifecycle before any specific design has been created so not a lot of info to go on at this stage.
The question I've had put forward from the infrastructure folks is "how many simultaneous users". Let's not debate the rationale of seeking only this one figure; it's just what's been asked for in this case! This is a web front end, SQL Server backend with a fairly fixed, easily quantifiable audience. To nail this down to actual simultaneous requests in a very rough fashion, the way I see it, it comes down to increasingly granular units of measurement:
Total audience
Simultaneous sessions
Simultaneous requests
Simultaneous DB queries
This doesn't account for factors such as web app caching, partial page requests, record volume etc and there's some creative license needed to define frequency of requests per user and number of DB hits and execution time but it seems like a reasonable starting point. I'm also conscious of the need to scale for peak load but that's something else that can be plugged into the simultaneous sessions if required. This is admittedly very basic and I'm sure there's more comprehensive guidance out there. If anyone can share their approach to this exercise or point me towards other resources that might make the process a little less ad hoc
I need to do some performance testing for an ASP.NET MVC application and specifically want to measure how many database queries each HTTP request results in. The data access layer is using LINQ-to-SQL. I'd like to be able to automate the tests so am looking for a good way to be able to do a before and after count of the number of SQL queries. The possibilities I can think of are: A performance monitor counter for the ASP.NET process, A system table in the MSSQL database that can be queried before and after each page request, A property somewhere in the System.Data.SQLClient namespace that tracks the number of queries executed by the process. Has anyone done this before and can perhaps point my down the right path?
View 1 RepliesWe have an ASP.NET application that uses SQL statements, where table names are unqualified. When compiled, it works fine, but when uncompiled, it complains and errors out, saying these tables dont' exist. (Qualified name looks like Select * from MyDatabase.mySchema.MyTable; Unqualified like Select * from MyTable) If you try these queries on the database, by yourself, it will take only the qualified names. What's going on? I thought Compiled vs Uncompiled apps should perform the same way codewise.
View 2 RepliesHow to add queries in to database using ajax (without page refresh).
View 1 RepliesA sample linq query from MSDN: var expensiveInStockProducts = from p in products where p.UnitsInStock > 0 && p.UnitPrice > 3.00M select p; Does this query select EVERY column from the database table immediately, or does it return some sort of pointer that retieves the actual column data on demand? ie. If there are 50 columns in my table and I only use a single p.UnitsInStock in my actual code, then am I retrieving 50 times more data than I expected?
View 2 RepliesWe have a web application using VS 2008, c#. We try to filter siteMap nodes based on security roles. We have our customized the mether GetRolesForUser() in RoleProvider class to determine a user's role. In this method, roles will be returned by querying an SQL Server database. However, we found that each time a page was loaded/refershed, this GetRolesForUser() was called, and the database would be queried. This is too MUCH and expensive. We thought the roles should be queried only once when a user logs in. After that, role info should be stored somewhere for this user, rather than query DB all the time.
View 3 Repliesanyone know that can we used select statement to called queries table in database or not?usually people used select statement to called common table in database.
View 4 RepliesI am very new on the C# and ASP scene and am after some advice on how to handle a senario. I have a asp website with 10 text boxes. These boxes form the basis of a user completed parameter selection. There is a button that will fire the query. The compliction is that some of the textboxes may be left blank and any combination may be filled in.
The only way i could think to do this is with countless IF statements. The user clicks the button and the process checks out the senarios and runs the corresponding SQL statement. The problem with this is that there are a vast amount of possible senarios depending on whether the user completes one box, all boxes, or a mix of any of them. The SQL query is the same for each senario bar the WHERE statement which changes depending on which text boxes are filled in. Is there another way of doing this or do i really need to write every possible senario out in full?
I have a page on my website that displays certain ASP charts based off the selection made in a menu control. I'm trying to implement functionality now which will allow me, in certain cases, to make hyperlinks in the columns of the chart control which will result in the current page reloading with specific data. So there are two ways to get certain charts to display: one through the menu, two through another chart's hyperlinked data point.
I would like to handle the hyperlink situation without the use of query strings (if that's possible) becuase functionality already exists for a menu selection plus I'd rather not have to handle user input necessary with any query string. Is there a way to programmatically set the ValuePath property of a menu control which I could (hopefully) do in a Chart_Click event?
In general terms, which way will require more server processing power and which way will return faster queries... if there is even a difference. The client's database is still on the dev MS SQL server but is essentially but the client has decided they want to collect two more fields of information. Both fields are going to be collection text data and probably varchar(300) will be sufficient for the column data types. Would it ultimately be more efficient to
Add two additional columns in the main table so the data is entered directly into each record, or Add an additional table (or two) with a foriegn key to the primary table that holds the info for each new field The SELECT statement for the main table could be modified to either add the new columns (a.NewColumn1 and a.NewColumn2) or it could contain nested SELECT statements that pull in the data from the other tables. Custom daisy-chained Insert or Update statements would be no problem and a cascade Delete relationship would take care of any deletions. I'm just trying to figure out which would be better from a performance standpoint?
How do I make the entire grid read only programatically?
View 7 RepliesIs there anything missing in IIS 6.0 that prevents me from (Insert into table) using MS-Access?
Explain: The application works fine under Visual Studio 2008 IDE the insert into table works fine with no error, Also I tested with hosting provider and works fine with no problem. but now I have published the same exact app in a dedicated server windows 2003 with
IIS 6.0 .NET framework 2.0 with latest service pack I gave IIS_WPG write/modify access to the folder where MS-Access database is located and database but at the time of insert an error pop-up. I need to install in the Server or settings in the IIS to recognize my MS-Access db is it some office runtime that I am missing. (BTW I am using OLEDB connection string in my C# )
Using System.Data.OleDb;
I can retrieve data off of it with no problem but when I try to insert is when it fails I thought the problem was Access Rights but I do not think is the case.
I have a gridview with bound fields and a templateField that receives data from a submit button which, depending upon the selected object, i.e. dropdown 1, 2, or 3, return a result set. The gridview also has a checkbox column which is used as a marker to determinie the rows to be added to and existing table. If a user selects multiple row, those rows are written to the database. Everything works.
Now, I need to add additional functionality to the gridview:
Upon selecting the checkbox, programmatically the accompanying row must become editable; for each row presented.
Deselected the checkbox, return the gridview row to a read-only state.
There are 14 columns, one of which is a dropdown which needs to maintain its default value.
Dim ds As New AccessDataSource
ds.DataFile = "c:InputTest.mdb"
ds.DataSourceMode = SqlDataSourceMode.DataSet [code]....
In IIS 7 you can create database connection strings. I suppose this must be encrypted and best protected by IIS. This is nice, but how do I access it programmatically?
View 7 RepliesI need to programmatically get all the reports an AD user has access to.
View 1 RepliesI have an ASP.NET page that creates directories, and in another page I upload some files in these folders, but when I upload a file in a directory, the below error appears:
Access to the path 'my path' is denied.
I have a GridView :
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I want to query the value of a particular field in a DB and if it's true, display the LinkButton. if false, I want the linkButton not to be displayed.
is there a way to access the GridView programmatically and make visible certain of its columns or manipulate its items ?
i know that i can set a Label's text by using this syntax:
lblMessage.Text = (string)GetGlobalResourceObject("resxFile", "message");
but what's the difference(benefit/drawbacks) to using this syntax:
lblMessage.Text = Resources.resxFile.message;
also, i just found out that this second method doesn't work for local resource files. is there a different syntax used for local resource files?
I've created an asp.net sitemap with nodes that I will have to make visible on the condition of the sql table the webpage of the node accesses.
Where is the code of my sitemap.
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Here is the code I have tried.
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Each time I run this code the item.target, item.value, item.text equals the sitemapnode title. Yet, it should be different than this. I was hoping to store the table title of the sitemapnode in the value property. The reason for this is to enable my boss to modify the sitemap without having to explore the C# code. I'm lucky that if I could get him to open the sitemapfile. He does not want to worry about the code breaking down when he makes an addition to the sitemap node.
I have found that I can change the value programmatically in C# but this would contrast with what my boss would want.