ADO.NET :: Converting SQL Queries To Linq?
Jul 31, 2010How to convert SQL Queries to Linq.is their any tool available to convert SQL Queries to Linq
View 2 RepliesHow to convert SQL Queries to Linq.is their any tool available to convert SQL Queries to Linq
View 2 RepliesWhen i see MVC Music store. They have used ADO.NET entity data model and used LINQ language to perform operation in DB.. Is there any way to use normal sql queries?
View 3 RepliesI use LINQ-SQL as my DAL, I then have a project called DB which acts as my BLL. Various applications then access the BLL to read / write data from the SQL Database.
I have these methods in my BLL for one particular table:
public IEnumerable<SystemSalesTaxList> Get_SystemSalesTaxList()
{
return from s in db.SystemSalesTaxLists
select s;
}
public SystemSalesTaxList Get_SystemSalesTaxList(string strSalesTaxID)
{
return Get_SystemSalesTaxList().Where(s => s.SalesTaxID == strSalesTaxID).FirstOrDefault();
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Is it possible to combine these 2 linq queries ?
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I'm trying to do something that on the face of it is very simple.
If I have 5 text boxes, and 1 of them is blank, I want to exclude that textbox from the query, rather than searching for where a field is blank.
I've tried to do a bit of research into dynamic linq queries, but have come up empty handed, or what I've found doesn't seem to quite answer my question.
I have my Linq query in which i need to find time difference(not days difference).
The field in database is datetime.
Dim ldtToday
As DateTime = TimeOfDay
Dim SR_RM_InnerJoin =
From SR
In lcntxRT60Entities.RtSReports _
Join RM
In lcntxRT60Entities.RtRMaster
On SR.RtRMaster.ReportID
Equals RM.ReportID _
Select SR, RM _
Where SR.TID = 1 _
And --(Check) SR.ReportDeliveryTime.Value.AddDays(1) < ldtToday
How can i check if the time field of the record is less than current time??
A 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 RepliesI am creating entries in a contract table using linq to sql.
One column needs to conditionally be assigned an application number from a range of values.
I'd like to simply increment the max existing value, however it is a multi-user application and I'm concerned about multiple contracts receiving the same app number if they happen too close together.
Is there a way to either force the entire thing to use the same transaction, or to execute both during the same submit?
how to improve the application performance while writing LINQ Queries ?Like the optimization techniques.
View 2 RepliesI've got the following LINQ query to my IQueryable service
Dim eventcount = EventService.QueryEvents().Count
Dim eventlist = EventService.QueryEvents().Skip((page - 1) * 5).Take(5).ToList
But I'm wondering if there's a way to do this without making two calls to the database?
i want to get masterized....in MVC
finding books and links for mvc..and learning linq queries
Is there a way to cap the number of records returned when an .Include() method is called on an ObjectQuery<>? Basically, if one of my entities is in a one-to-many relationship, such as a Band entity to a list of Fan entities (where a band can have any number of fans), how can I limit the number of fans returned?
In the example: var band = ctx.Bands.Include("Fans").SingleOrDefault(b => b.BandId == someBandId);
If I use the Include, it will return all fans. How can I query that Fans navigation property to return only a subset or max?
I've got a linq to sql query that pulls data from 2 different tables and contains an or statement:
[Code]....
The problem I've got is that some queries match both sides of the or statement so it returns the same record twice.
How can I eliminate these duplicates quickly and easily?
I am working on asp.net 3.5 and in MVC using Linq to SQL classes. In my MVC project i am calling stored procedure using linq to sql that conatin query joining two tables.Below is my code in Partial class
[
Function(Name="dbo.GetUserWiseThreadDetail_SP")]
[ResultType(typeof(Thread))]
[ResultType(typeof(Reply))]
public
IMultipleResults GetUserWiseThreadDetail_SP([Parameter(DbType="VarChar(30)")]
string userID)
{
ExecuteResult result = this.ExecuteMethodCall(this,
(MethodInfo)(MethodInfo.GetCurrentMethod())), userID);
return ((IMultipleResults)(result.ReturnValue));
}
In one of the controller i have made one more class
public class
MypostIndexData
{
public
IEnumerable<Thread> Thrds {
get;
set; }
public
IEnumerable<Reply> Repls {
get;
set; }
public MypostIndexData(IEnumerable<Thread>
thrds,IEnumerable<Reply> repls)
{
this.Thrds=thrds;this.Repls=repls;
}
}
finally coding of controller action method
ForumDataContext pmforum = new
PMForumDataContext();
public
ActionResult MyPosts(string userId)
{
IEnumerable<Thread>thrds;
IEnumerable<Reply>repls;
IMultipleResults result = pmforum.GetUserWiseThreadDetail_SP(userId); (this satement doesnot give any result,if i execute stored proc in
sql it give the results)
thrds = result.GetResult<Thread>();
List<Thread> thrdlist =
new
List<Thread>(thrds);
repls = result.GetResult<Reply>();
List<Reply> replylist;
if (repls !=
null)
{
replylist = new
List<Reply>(repls);
}
return View(new
MypostIndexData(thrds,repls));
I am unable to understand why i am not getting any results?
Is there a way to combine the LINQ queries together and have access to both of the results independently?
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The following code works fine for converting an XML data set to be enumerable for Linq.
'Query webservice for data
Dim propertyInfo As String = myService.GetProperty(userName, password, Acct)
' Create a new DataSet.
[code]...
However, it does not retain the xml tags in the Linq enumerablerable dataset ('newDataSet2"). I don't think I can rely on the array index order as being the same everytime, so this would obviously cause a problem if I'm trying to align the array items up to my database fields. How can I make newDataSet2 retain the XML tags (column headings) to insure I know what data field each array item belongs to?
I have problem in converting date to string I am using cstr(p.tripstart) , which is returning Date as 12 Aug 2010 12:AM I need to make formating This is my code :
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We have two related tables (inventory, inventoryLocalization) and a t-sql query works on them as follows..
select inv.[code],
coalesce(inL.name, inL2.name) as [name],
coalesce(inL.description, inL2.description) as [description]
from dbo.[inventory] inv
left join dbo.[inventoryLocalization] inL on inv.code = inL.code and inL.language = 'de'
left join dbo.[inventoryLocalization] inL2 on inv.code = inL2.code and inL2.language = 'en'
where inv.[code] like '15.' + '%'
order by inv.[code];
to performance improvement, we will try to use these tables from cache not from RDBMS directly.
for an asp.net 4.0 project, by c#. We've took both tables to chache with a DataSet and we can reach both of them through that DataSet.
DataSet ds = UtilityCache.getCachedDataSet();
"ds.Tables[0]" is inventory Table and "ds.Tables[1]" is inventoryLocalization Table
But how can we convert above T-Sql syntax to linq2Sql. is it possible to use coalesce for select statement and to join on two tables with multiple conditions ?
I am converting my datatable to LISt using LINQ how do I handle nulls coming from database
List<Port> portDetails = new List<Port>();
DataTable dt = ds.Tables[0];
portDetails = (from q in dt.AsEnumerable()
select new Port
{
PortCode = q.Field<string>("Code"),
ExtCode = q.Field<string>("Nb"),
Name = q.Field<string>("Name"))
}).ToList();
In the above query if Code is null I do not want property portcode to be set to the value it should only set if it is not null or not blank
PortCode = q.Field<string>("Code"),
What should be syntax
I was trying somethign like this which doesnt work
Portcode = q.Field<bool>("Code") == null ? null : q.Field<bool>("Code")
I'm currently trying to work out the best way to build this web application, which will then be intergrated on other systems, such as WinForms, Intranets etc.
We hope to include the usual layers i.e. DAL, BLL, BOL and UI but I have been experimenting with Entity Framework 4 and WCF Data Services and managed to get something in place where I was using WCF as a gateway to EF4.
i.e. Adding a Service Reference to my project and then using the EF4 context and writing LINQ queries against the DB
e.g.[Code]....
Now with the current setup I would still need to write a DAL Class Library, that interacts with the Data Service, because as I said WCF Data Services only seems to be a gateway, I can't see where to put the code (above) in the Data Service and then how I could these methods.
My questions are: 1. How do I develop a WCF Data Service in such a way to allow this behaviour - I know how I could do it using ASMX web service, something like [Code]....
2. If I am to use WCF Data Services, how is serialization handled (if at all) - again I know how to do something in ASMX web services
3. Again, If I am to use WCF, how do I add Security and only allow my applications to access the web service - for obvious reasons
4. Would it be possible / logical to also include the Business Logic Layer into the web service?
I've added a database to one of my projects and I'm wondering how I can get intellisense for them.
Basically I have no how I can query the database that I've added to the project. I know SQL fairly well, but I don't know how I can write queries within vb.net and have them display.
I can get, so intellisense will probably be invaluable.
I have a query which gets the text from a textbox and inputs it into the database.
It works fine if the value is something like Taylor but errors when it's O'Neill because the apostrophe gives a syntax error unclosed quotation mark Is there a way to add O'Neill to the database with the apostrophe still there?
I don't want to replace it with a double single quote I want it to be put in the database as it shows.
What would be equivalent linQ query for:
I am using linQ for get these data to silverlight so I cant use execute query in silverlight and have to go with LInQ. can someone point me for easier way to convert similar queries or any tips.
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In my web application, I need to run a lot of sql queries for a specific operation. For example, first I run a select command , get results. If they fulfill my requirement, I insert some values by insert command, else I update and insert...and so on. I need to execute 8-10 commands for each specific operation. For this , I have created a <asp:Sqldatasource> in aspx page and I run queries by SqlDataSource1.Select, SqlDataSource1.InsertCommand etc. I dont think , its a right approach . Further, I need to preserve data consistency. Say my 5 commands executes successfully and then sql or something else, throws an error and 5 commands left untouched. Then, it will create me a problem. And my current logic will fail, as it works on step by step basis.
View 3 RepliesI'm going to try to use the WebClient object in .NET to grab the response querystring values sent back by the resource.
I'm familiar with grabbing xml, json, etc. but typically I haven't worked with many NVP type of APIs in terms of grabbing the query immediately from an response sent back from a resource server-side. So how is a query sent back, in the body of a response, header, what? How do you grab it, with the stream object just like you do anything else? This questions relates to the environment I work in C# but really it relates to the web as a whole as well which is why I tagged this in multiple categories as a Request/Response is not MS specific however I am also at the same time trying to utilize the .NET WebClient object.