Trying To Compare LINQ-to-Entity To Date Results In Error
Mar 14, 2011
I have a simple If..Then like so:
If rhcexists.First.SignatureDate > Date.Today.AddMonths(-6) Then
End If
rhcexists is a simple query to the Entity Model:
Dim rhcexists = From p In dbContracts.Signatures _
Where p.StudentID = CStr(Session("people_code_id")) _
And p.ContractType = "rhc" _
Order By p.ID Descending _
Select p
Problem is that this comparison results in an error:
LINQ to Entities does not recognize the method 'System.Object get_Item(System.String)' method, and this method cannot be translated into a store expression.
This is occurring on the If clause. Any ideas why this occurring and how I can fix it?
I then check whether one of the result values is more recent than six months ago using an if..then like so:
If rhcexists.First.SignatureDate > Date.Today.AddMonths(-6) Then End If
However, if there are no results returned this will return an error. Is there a way for me to tell it to act as if the date is older than six months if there is no value at all? e.g., could I in pseudo do something like:
If Exists(rhcexists.First.SignatureDate, Date.Today.AddMonths(-8)) > Date.Today.AddMonths(-6) Then End If
I'm a newbie to this so bear with me. From what I've read online LINQ to Entity should see the relationships without having to specify the joins between multiple tables. I have a relationship that goes across 4 tables Employee, EmployeeDepartmentLink, EmployeeProjectLink, and Project. The idea is an employee can be in multiple departments and work on multiple projects with it being specified which department the employee is in for that project.
This is a C# MVC3 program connecting to a SQL database using VS 2010 Express.
I have no problem with running this query to find employees on a project:
[Code]....
Tring to do the reverse, finding projects that an employee worked on results in an error:
[Code]....
Error message: The specified type member 'EmployeeDepartmentLinks' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported. So I have 2 questions,
1) Why would it work in one direction and not the other? I've played around with it for a couple days with the same results.
2) Does it matter that my primary key and foreign keys are not named the same since all the relationships are connected in SQL? Ex: in Employee (EmployeePK)--(EmployeeFK) in EmployeeDepartmentLink Trying different stuff in LINQPad I was able to get the 2nd query to work if I specified all the joins which I thought was not neccesary with LINQ to Entity. I converted an SQL query that I made on the server into a LINQ query below which works.
I have a "simple" method that takes a Linq entity containing the information I want to update. The method then creates a list of counties the information is to be updated for, and tries to update the information for each county.
So user goes in fills form out selects update All counties, and the information in the form should be updated for all the counties for the member. Here is the code.
[Code]....
The first pass through the foreach runs perfectly, the second time through I get an error: Cannot attach an entity that already exists.
What is best way to work around this?
I have though about putting the foreach loop in my business_logic layer, and have it pass both the newRecord and OldRecord, but figured I would ask, before making the code change.
How to get the date at which a record is created in SQL?..i.e, if i add a record to a database table db1 at 8/10/2010 11:30, I want to get the datetime, i.e 8/10/2010 11:30..;.Also let me know how to compare datetime values..
if(8/10/2010 11:30 >8/10/2010 10:30) will work or not?
i would like to compare the current date with the date entered by user..however, i'm encountering errors so far..
i tried something like this:
<asp:TextBox id="txtDate1" runat="server" /> <asp:CompareValidator runat="server" ErrorMessage="The date must be greater than today" ControlToValidate="txtDate1" type="date" ValuetoCompare="DateTime.Today.ToShortDateString()" />
and i got an error stating that the value of DateTime.Today.ToShortDateString() of the ValueToCompare property of "" cannot be converted to type 'date' i also tried ValueToCompare="DateTime.Now.Date()" and i got the same error message.
How to create Jobs, I am using SQL 2005, i need a query which should get current date and compare current date with date in table and Send Email according to Job scheduled.
C#, ASP.NET MVC, SQL Server 2008 ( Same version & SP level), Linq-To-SQL ORM
I'm trying to diagnose an exception I'm receiving:
"Specified cast is not valid." at System.Data.Linq.IdentityManager.StandardIdentityManager.SingleKeyManager2.TryCreateKeyFromValues(Object[] values, V& v) at System.Data.Linq.IdentityManager.StandardIdentityManager.IdentityCache2.Find(Object[] keyValues) at System.Data.Linq.IdentityManager.StandardIdentityManager.Find(MetaType type, Object[] keyValues) at System.Data.Linq.CommonDataServices.GetCachedObject(MetaType type, Object[] keyValues) at System.Data.Linq.ChangeProcessor.GetOtherItem(MetaAssociation assoc, Object instance) at System.Data.Linq.ChangeProcessor.BuildEdgeMaps() at System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges() at Repository.Save() at etc....
The problem is that this is occurring only on our servers, not on our local development boxes. I've tracked it down to a single property we're modifying:
event.SalesForceId = "701Q0000000AOTIIA4";
If I comment out that line, everything works fine.
I've tried:
1 ) waxing all of the code on the server and redeploying. Same issue. 2 ) Pulling down a copy of the server DB and trying it locally. Works fine. 3 ) Trying another IIS environment we have setup on the same box. Same issue. 4 ) Physically comparing ( using AdeptSQL ) both local and remote schemas. No differences. 5 ) Verifying the datatypes of both columns ( local and remote ) are the same. Also, this column is a FK to another table. I verified that both are of the same data type, down to the collation.
The server is Windows Server 2008 and the local box is Windows 7 x64. Both have all important updates setup.
The only thing I can think of is perhaps since the database and web server are on different boxes that could be an issue? Otherwise, I'm completely stumped.
string strCondition = "FirstName=='abc'" from p in People.Where(strCondition) select p
In our architecture we are usign both Linq-Sql as well Linq-Entity. So please give some thoughts wehter it is possible or not and is there any way to perform this?
I have a date textbox. It has three validators on it. One is RequiredFieldValidator, second is CompareValidator and the third is RegularExpressionValidator.
CompareValidator checks for LessThanEqual for current date. For example if user enters date greater then todays' then it should display error message. It does that.
Problems is if user enters invalidate e.g., 2009/05/0d then I see two error messages. One for invalid date and one for compare. In this specfic case I want to see only one error that 'Date is invalid'. But some how I see two mesages.
I can't seem to figure out how to write this query properly. I've tried various combinations but nothing's worked yet. Below is the relevant portion of my database model: I need to select the products that match a given Category and Group, and that match a given Year, Make, Model, submodel. This I've done below:
ItemList = From P In gDataContext.Products.Include("Groups").Include("Groups.Category1").Include("LookupYearMakeModels") From G In P.Groups Where G.Category = Cat And G.Grp = Group From Y In P.LookupYearMakeModels Where Y.Year = YMM.Year And Y.Make = YMM.Make And Y.Model = YMM.Model And Y.Submodel = YMM.Submodel Select P
I now also have to select products that match the Category, and Group but are Universal (Product.Univeral = True). I'm currently writing two queries, the one above and the one below. I'm merging the results of the two by simply using ItemList.AddRange(ItemList2) ItemList2 = From P In gDataContext.Products.Include("Groups").Include("Groups.Category1") where P.Universal From G In P.Groups Where G.Category = Cat And G.Grp = Group Select P But I want to combine both queries into one and avoid merging the results. How can I do it?
I have a textbox control with a calendarExtender. I want to make the user select a date subsequent to Today. I have a public function, called display_error, written that displays some text in case of validation not successfull. So in this case, the validation of the date inserted by user would look like [Code]....
So, my textBox.text is a string, which I need to convert to Date to compare it to Today. Here's what I've written [Code]....
I've tried different methods, like Parse, but I keep getting the same error, String was not recognized as valid DateTime.
I have two TextBox controls for start date & end date input. I have to validate that end date is not greater than start date & the difference between start date & end date is not more than 12 months.
