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  • How to implement a left outer join in the Entity Framework.

    - by user206736
    I have the following SQL query:- select distinct * from dbo.Profiles profiles left join ProfileSettings pSet on pSet.ProfileKey = profiles.ProfileKey left join PlatformIdentities pId on pId.ProfileKey = profiles.Profilekey I need to convert it to a LinqToEntities expression. I have tried the following:- from profiles in _dbContext.ProfileSet let leftOuter = (from pSet in _dbContext.ProfileSettingSet select new { pSet.isInternal }).FirstOrDefault() select new { profiles.ProfileKey, Internal = leftOuter.isInternal, profiles.FirstName, profiles.LastName, profiles.EmailAddress, profiles.DateCreated, profiles.LastLoggedIn, }; The above query works fine because I haven't considered the third table "PlatformIdentities". Single left outer join works with what I have done above. How do I include PlatformIdentities (the 3rd table) ? I basically want to translate the SQL query I specified at the beginning of this post (which gives me exactly what I need) in to LinqToEntities. Thanks

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  • Update a record in L2S and L2E

    - by 5YrsLaterDBA
    I was told in L2S, the code for update and insert are the same, db.InsertOnSubmit(row); db.SubmitChanges(); and L2S will check to see if it is a insert or update and act approprately in the background. Is that true? How about L2E? I tested, looks like in L2E it is not like that. Maybe I did something wrong.

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  • How do I save an object that contains and EntitySet?

    - by Pete
    Say I have an User (mapped to a User table) and the Edit view (in MVC) displays a multiselectlist of Modules (mapped to a Modules table) that user can access, with the Modules pre-selected based on the User's EntitySet of Modules. I have tried saving the User then deleting all User_Modules manually and adding them back based on what's selected on submit, but the User has a null EntitySet for User.User_Modules. I cannot find the correct way to handle this scenario anywhere online. Can anyone help?

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  • DataContext Refresh and PropertyChanging & PropertyChanged Events

    - by Scott
    I'm in a situation where I am being informed from an outside source that a particular entity has been altered outside my current datacontext. I'm able to find the entity and call refresh like so MyDataContext.Refresh(RefreshMode.OverwriteCurrentValues, myEntity); and the properties which have been altered on the entity are updated correctly. However neither of the INotifyPropertyChanging INotifyPropertyChanged appear to be raised when the refresh occurs and this leaves my UI displaying incorrect information. I'm aware that Refresh() fails to use the correct property getters and setters on the entity to raise the change notification events, but perhaps there is another way to accomplish the same thing? Am I doing something wrong? Is there a better method than Refresh? If Refresh is the only option, does anyone have a work around?

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  • How to write this Link2Sql select query

    - by RememberME
    I have 3 tables: subcontracts, companies and contacts. Each table has a active_status flags which shows that the item is still active (hasn't been deleted). Each contact has a company_id field which stores the id of the contact's company. Each subcontract has a company_id field which stores the subcontract's company. Each company has a company_id field which holds its guid and a primary_company field, b/c the company could be a subsidiary. If it's a subsidiary, the primary_company field holds the id of the primary company. I have a subcontract form. On the form, I have a drop-down of contacts which are stored in a contact table. Currently the drop-down lists all contacts. I would like to have the drop-down only list contacts which belong to the subcontract's company or any of that company's subsidiaries. I have the following query which I use elsewhere in the program to pass a company_id and get its subsidiaries. public IQueryable<company> GetSubsidiaryCompanies(Guid id) { return from c in db.companies where c.primary_company == id && c.active_status == true select c; } This is my current contact selection public IQueryable<contact> GetContacts() { return from c in db.contacts where c.active_status == true orderby c.contact_name select c; } What I need to do is pass it the subcontract.company_id and then only return the contacts where contact.company_id == subcontract.company_id or contact.company_id == one of the subsidiary ids.

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  • Returning IEnumerable<T> vs IQueryable<T>

    - by stackoverflowuser
    what is the difference between returning iqueryable vs ienumerable. IQueryable<Customer> custs = from c in db.Customers where c.City == "<City>" select c; IEnumerable<Customer> custs = from c in db.Customers where c.City == "<City>" select c; Will both be deferred execution? When should one be preferred over the other?

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  • LinqToXML why does my object go out of scope? Also should I be doing a group by?

    - by Kettenbach
    Hello All, I have an IEnumerable<someClass>. I need to transform it into XML. There is a property called 'ZoneId'. I need to write some XML based on this property, then I need some decendent elements that provide data relevant to the ZoneId. I know I need some type of grouping. Here's what I have attempted thus far without much success. **inventory is an IEnumerable<someClass>. So I query inventory for unique zones. This works ok. var zones = inventory.Select(c => new { ZoneID = c.ZoneId , ZoneName = c.ZoneName , Direction = c.Direction }).Distinct(); No I want to create xml based on zones and place. ***place is a property of 'someClass'. var xml = new XElement("MSG_StationInventoryList" , new XElement("StationInventory" , zones.Select(station => new XElement("station-id", station.ZoneID) , new XElement("station-name", station.ZoneName)))); This does not compile as "station" is out of scope when I try to add the "station-name" element. However is I remove the paren after 'ZoneId', station is in scope and I retreive the station-name. Only problem is the element is then a decendant of 'station-id'. This is not the desired output. They should be siblings. What am I doing wrong? Lastly after the "station-name" element, I will need another complex type which is a collection. Call it "places'. It will have child elements called "place". its data will come from the IEnumerable and I will only want "places" that have the "ZoneId" for the current zone. Can anyone point me in the right direction? Is it a mistake select distinct zones from the original IEnumerable? This object has all the data I need within it. I just need to make it heirarchical. Thanks for any pointers all. Cheers, Chris in San Diego

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  • EF4. Add a object with relationship causes full table select

    - by Fujiy
    Ex 1: "autor.ComentariosWorkItens.Add(comentarioWorkItem);" autor.ComentariosWorkItens makes EF4 load all ComentariosWorkItens. Ex 2: comentarioWorkItem.Usuario = autor; Fixup make EF load all ComentariosWorkItens too: private void FixupUsuario(Usuario previousValue) { if (previousValue != null && previousValue.ComentariosWorkItens.Contains(this)) { previousValue.ComentariosWorkItens.Remove(this); } if (Usuario != null) { if (!Usuario.ComentariosWorkItens.Contains(this)) { Usuario.ComentariosWorkItens.Add(this); } } } How can I prevent this?

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  • Duplicate elements when adding XElement to XDocument

    - by Andy
    I'm writing a program in C# that will go through a bunch of config.xml files and update certain elements, or add them if they don't exist. I have the portion down that updates an element if it exists with this code: XDocument xdoc = XDocument.Parse(ReadFile(_file)); XElement element = xdoc.Elements("project").Elements("logRotator") .Elements("daysToKeep").Single(); element.Value = _DoRevert; But I'm running into issues when I want to add an element that doesn't exist. Most of the time part of the tree is in place and when I use my code it adds another identical tree, and that causes the program reading the xml to blow up. here is how I am attempting to do it xdoc.Element("project").Add(new XElement("logRotator", new XElement("daysToKeep", _day))); and that results in a structure like this(The numToKeep tag was already there): <project> <logRotator> <daysToKeep>10</daysToKeep> </logRotator> <logRotator> <numToKeep>13</numToKeep> </logRotator> </project> but this is what I want <project> <logRotator> <daysToKeep>10</daysToKeep> <numToKeep>13</numToKeep> </logRotator> </project>

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  • Can't get Sum() working in Northwind example

    - by Vince
    Hi, The following code is generating a runtime error and I have no idea why. from o in Orders group o by o.Employee into employeeOrders select new { employeeOrders.Key.EmployeeID, employeeOrders.Key.FirstName, Orders = from eord in employeeOrders orderby eord.OrderID select new { eord.OrderID, eord.OrderDate, OrderTotal=eord.OrderDetails.Sum (od => od.UnitPrice) } } The error is Member access 'System.Decimal UnitPrice' of 'LINQPad.User.OrderDetails' not legal on type 'LINQPad.User.Orders I've also tried this in VS2010 with a standard drag and drop data context and same thing. Thanks in advance

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  • Cannot Translate to SQL using Select(x => Func(x))

    - by Dan
    I'm slowly learning the ins and outs of LINQtoSQL, but this is confusing me. Here is the statement I have: IQueryable<IEvent> events = (from e in db.getEvents() select e).Select(x => SelectEvent(x, null)); What the SelectEvent does can be explained in this answer here. I am not using the .toList() function as I don't want potentially thousands of records brought into memory. public IEvent SelectEvent(SqlServer.Event ev, EventType? type) { // Create an object which implements IEvent // I don't have the code in front of me, so forgive the lack of code } My question is really for the Select() method. I get the "Cannot translate to SQL" error and the Select() is listed in the error message. Clueless on this one :-/.

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  • LinqToSQL: Not possible to update PrimaryKey?

    - by Zuhaib
    I have a simple table (lets call it Table1) that has a NVARCHAR field as the PK. Table1 has no association with any other tables. When I update Table1's PK column using LinqToSQL it fails. If I update other column it succeeds. I could delete this row and insert new one in Table1, but I don't want to. There is a transaction table which has Table1's PK column as a column. When the PK of Table1 is changed I want no effect in the transaction table. But when the row from Table1 is deleted, I want the transaction rows to be deleted. The cascading is done via Trigger. As there is not association between these two tables, if I update the PK column of Table1 using normal SQL, it works and there is no effect on the transaction table as expected. When I delete the row the trigger deletes the rows from transaction table. For this reason I can't delete and then add new row in Table1. So what can be done to successfully update the PrimaryKey of the Table1?

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  • How can I improve the performance of LinqToSql queries that use EntitySet properties?

    - by DanM
    I'm using LinqToSql to query a small, simple SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of what makes LinqToSql so appealing. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance besides resorting to doing all the joins manually? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view. Update Here are the table definitions for the example I used in my question: create table Order ( Id int identity(1, 1) primary key, ProductName ntext null ) create table Customer ( Id int identity(1, 1) primary key, OrderId int null references Order (Id) )

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  • Error message on using LinqDataSource in webforms

    - by naveen
    Coding Platform: ASP.NET 4.0 I am binding a GridView with LinqDataSource with AutoDelete functionality enabled. GridView is bound to the Products Table. I have a Products Table and a Category Table with an association on CategoryID. If I try to delete a Category that is referred in the Products Table I cannot do that. Its is totally acceptable, but I want the end user to be notified with some error message. Where to catch this error message?

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  • How to write this query in Linq2Sql

    - by RememberME
    I have a table company which holds the company_id, company_name and other details. I have a table subcontracts which has a company_id column that maps to company.company_id. How can I write a select statement to get all companies which have not been assigned to a subcontract? IE The company_id cannot be found in subcontracts.company_id

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  • How to create view model without sorting collections in memory.

    - by Chevex
    I have a view model (below). public class TopicsViewModel { public Topic Topic { get; set; } public Reply LastReply { get; set; } } I want to populate an IQueryable<TopicsViewModel> with values from my IQueryable<Topic> collection and IQueryable<Reply> collection. I do not want to use the attached entity collection (i.e. Topic.Replies) because I only want the last reply for that topic and doing Topic.Replies.Last() loads the entire entity collection in memory and then grabs the last one in the list. I am trying to stay in IQueryable so that the query is executed in the database. I also don't want to foreach through topics and query replyRepository.Replies because looping through IQueryable<Topic> will start the lazy loading. I'd prefer to build one expression and have all the leg work done in the lower layers. I have the following: IQueryable<TopicsViewModel> topicsViewModel = from x in topicRepository.Topics from y in replyRepository.Replies where y.TopicID == x.TopicID orderby y.PostedDate ascending select new TopicsViewModel { Topic = x, LastReply = y }; But this isn't working. Any ideas how I can populate an IQueryable or IEnumerable of TopicsViewModel so that it queries the database and grabs topics and that topic's last reply? I am trying really hard to avoid grabbing all replies related to that topic. I only want to grab the last reply. Thank you for any insight you have to offer.

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  • data is not getting ordered by date

    - by raging_boner
    Can't get list sorted by date. How to show data ordered by date? XDocument doc = XDocument.Load(Server.MapPath("file.xml")); IEnumerable<XElement> items = from item in doc.Descendants("item") orderby Convert.ToDateTime(item.Attribute("lastChanges").Value) descending where item.Attribute("x").Value == 1 select item; Repeater1.DataSource = items; Repeater1.DataBind(); Xml file looks like this: <root> <items> <item id="1" lastChanges="15-05-2010" x="0" /> <item id="2" lastChanges="16-05-2010" x="1" /> <item id="3" lastChanges="17-05-2010" x="1" /> </items> </root>

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  • Do entity collections and object sets implement IQueryable<T>?

    - by Chevex
    I am using Entity Framework for the first time and noticed that the entities object returns entity collections. DBEntities db = new DBEntities(); db.Users; //Users is an ObjectSet<User> User user = db.Users.Where(x => x.Username == "test").First(); //Is this getting executed in the SQL or in memory? user.Posts; //Posts is an EntityCollection<Post> Post post = user.Posts.Where(x => x.PostID == "123").First(); //Is this getting executed in the SQL or in memory? Do both ObjectSet and EntityCollection implement IQueryable? I am hoping they do so that I know the queries are getting executed at the data source and not in memory. EDIT: So apparently EntityCollection does not while ObjectSet does. Does that mean I would be better off using this code? DBEntities db = new DBEntities(); User user = db.Users.Where(x => x.Username == "test").First(); //Is this getting executed in the SQL or in memory? Post post = db.Posts.Where(x => (x.PostID == "123")&&(x.Username == user.Username)).First(); // Querying the object set instead of the entity collection. Also, what is the difference between ObjectSet and EntityCollection? Shouldn't they be the same? Thanks in advance!

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  • why datetime.now not work when I didn't use tolist?

    - by MemoryLeak
    When I use datacontext.News .Where(p => p.status == true) .Where(p => p.date <= DateTime.Now) .ToList(); the system will return no results; When I use datacontext.News .Where(p => p.status == true) .ToList() .Where(p => p.date <= DateTime.Now) .ToList(); system will return expected results. Can anyone tell me what's up? Thanks in advance !

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  • How To Join Tables from Two Different Contexts with LINQ2SQL?

    - by RSolberg
    I have 2 data contexts in my application (different databases) and need to be able to query a table in context A with a right join on a table in context B. How do I go about doing this in LINQ2SQL? Why?: We are using a SaaS product for tracking our time, projects, etc. and would like to send new service requests to this product to prevent our team from duplicating data entry. Context A: This db stores service request information. It is a third party DB and we are not able to make changes to the structure of this DB as it could have unintended non-supportable consequences downstream. Context B: This data stores the "log" data of service requests that have been processed. My team and I have full control over this DB's structure, etc. Unprocessed service requests should find their way into this DB and another process will identify it as not being processed and send the record to the SaaS product. This is the query that I am looking to modify. I was able to do a !list.Contains(c.swHDCaseId) initially, but this cannot handle more than 2100 items. Is there a way to add a join to the other context? var query = (from c in contextA.Cases where monitoredInboxList.Contains(c.INBOXES.inboxName) select new { //setup fields here... });

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  • Is an object still connected to a list after FirstOrDefault?

    - by Cynthia
    Here's my code: Event thisEvent = (from i in list where (i.eventID == eventID) select i).FirstOrDefault(); if (thisEvent != null) { thisEvent.eventResolved = resolved; thisEvent.eventSequence.Add(item); } "list" is a collection of IEnumerable, i.e. IEnumerable<Event> list; What I'm wondering is: after creating thisEvent using FirstOrDefault, is thisEvent still connected to list? In other words, when I change the two properties, eventResolved and eventSequence, is "list" actually changed, or is thisEvent just some totally disconnected copy of an item in "list"?

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  • How to limit select items with L2E/S?

    - by orlon
    This code is a no-go var errors = (from error in db.ELMAH_Error select new { error.Application, error.Host, error.Type, error.Source, error.Message, error.User, error.StatusCode, error.TimeUtc }).ToList(); return View(errors); as it results in a 'requires a model of type IEnumerable' error. The following code of course works fine, but selects all the columns, some of which I'm simply not interested in: var errors = (from error in db.ELMAH_Error select error).ToList(); return View(errors); I'm brand spanking new to MVC2 + L2E, so maybe I'm just not thinking in the right mindset yet, but this seems counter-intuitive. Is there an easy way to select a limited number of columns, or is this just part of using an ORM?

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