Asp.Net MVC3, Update query in Linq - asp.net

I'd like to know how to run this query in Linq way.
UPDATE orders SET shipDate = '6/15/2012' WHERE orderId IN ('123123','4986948','23947439')
My Codes,
[HttpGet]
public void test()
{
EFOrdersRepository ordersRepository = new EFOrdersRepository();
var query = ordersRepository.Orders;
// How to run this query in LINQ
// Query : UPDATE orders SET shipDate = '6/15/2012' WHERE orderId IN ('123123','4986948','23947439')
}
EFOrdersRepository.cs
public class EFOrdersRepository
{
private EFMysqlContext context = new EFMysqlContext();
public IQueryable<Order> Orders
{
get { return context.orders; }
}
}
EFMysqlContext.cs
class EFMysqlContext : DbContext
{
public DbSet<Order> orders { get; set; }
}

Actually it's pretty easy check the following code
EFOrdersRepository db = new EFOrdersRepository();
int[] ids= new string[] { "123123", "4986948", "23947439"};
//this linq give's the orders with the numbers
List<Order> orders = db.Order().ToList()
.Where( x => ids.Contains(x.orderId.Contains));
foreach(var order in orders)
{
order.ShipDate = '06/15/2012';
db.Entry(usuario).State = EntityState.Modified;
}
db.SaveChanges();

Something like this should work (warning Pseudo code ahead!!)
EDIT I like using the Jorge's method of retrieving the orders better (using contains), but leaving this here as another alternative. The statements below the code sample still hold true however.
[HttpGet]
public void test()
{
EFOrdersRepository ordersRepository = new EFOrdersRepository();
var query = ordersRepository.Orders.Where(x=>x.orderId == '123123' ||
x.orderId == '4986948' || x.orderId = '23947439').ToList();
foreach(var order in query){
var localOrder = order;
order.ShipDate = '06/15/2012';
}
ordersRepository.SaveChanges();
}
Basically, LINQ does not do 'bulk updates' well. You either have to fetch and loop through your orders or write a stored procedure that can take an array of ids and bulk update them that way. If you are only doing a few at a time, the above will work ok. If you have tons of orders that need to be updated, the ORM probably will not be the best choice. I look forward to see if anyone else has a better approach.
Disclaimer: the var localOrder = order line is to ensure that there are no modified closure issues. Also, ReSharper and other tools may have a less verbose way of writing the above.

Note: You need to call SaveChanges from your DBContext at the end
Short answer:
var f = new[] { 123123, 4986948, 23947439 };
var matchingOrders = orders.Where(x => f.Contains(x.ID)).ToList();
matchingOrders.ForEach(x => x.ShipDate = newDate);
Complete test:
// new date value
var newDate = new DateTime(2012, 6, 15);
// id's
var f = new[] { 123123, 4986948, 23947439 };
// simpulating the orders from the db
var orders = Builder<Order2>.CreateListOfSize(10).Build().ToList();
orders.Add(new Order2 { ID = 123123 });
orders.Add(new Order2 { ID = 4986948 });
orders.Add(new Order2 { ID = 23947439 });
// selecting only the matching orders
var matchingOrders = orders.Where(x => f.Contains(x.ID)).ToList();
matchingOrders.ForEach(x => Console.WriteLine("ID: " + x.ID + " Date: " + x.ShipDate.ToShortDateString()));
// setting the new value to all the results
matchingOrders.ForEach(x => x.ShipDate = newDate);
matchingOrders.ForEach(x => Console.WriteLine("ID: " + x.ID + " Date: " + x.ShipDate.ToShortDateString()));
Output:
ID: 123123 Date: 1/1/0001
ID: 4986948 Date: 1/1/0001
ID: 23947439 Date: 1/1/0001
ID: 123123 Date: 6/15/2012
ID: 4986948 Date: 6/15/2012
ID: 23947439 Date: 6/15/2012

In ORMs, You have to fetch the record first make the change to the record then save it back. To do that, I will add an UpdateOrder method to my Repositary like this
public bool UpdateOrder(Order order)
{
int result=false;
int n=0;
context.Orders.Attach(order);
context.Entry(order).State=EntityState.Modified;
try
{
n=context.SaveChanges();
result=true;
}
catch (DbUpdateConcurrencyException ex)
{
ex.Entries.Single().Reload();
n= context.SaveChanges();
result= true;
}
catch (Exception ex2)
{
//log error or propogate to parent
}
return result;
}
And i will call it from my Action method like this
int orderId=123232;
var orders=ordersRepository.Orders.Where(x=> x.orderId.Contains(orderId)).ToList();
if(orders!=null)
{
foreach(var order in orders)
{
order.ShipDate=DateTime.Parse('12/12/2012);
var result= ordersRepository.UpdateOrder();
}
}
In this Approach, if you have to update many number of records, you are executing thatn many number of update statement to the database. In this purticular case, i would like to execute the Raw SQL statement with only one query using the Database.SqlQuery method
string yourQry="UPDATE orders SET shipDate = '6/15/2012'
WHERE orderId IN ('123123','4986948','23947439')";
var reslt=context.Database.SqlQuery<int>(yourQry);

Related

how we can return a status code for the serialized JSON object using Newtonsoft.net

I have this Action method which act as an API end point inside our ASP.NET MVC-5, where it search for a username and return the username Phone number and Department from Active Directory (we are serializing the object using Newtonsoft.net):-
public ActionResult UsersInfo2()
{
DomainContext result = new DomainContext();
try
{
// create LDAP connection object
DirectoryEntry myLdapConnection = createDirectoryEntry();
string ADServerName = System.Web.Configuration.WebConfigurationManager.AppSettings["ADServerName"];
string ADusername = System.Web.Configuration.WebConfigurationManager.AppSettings["ADUserName"];
string ADpassword = System.Web.Configuration.WebConfigurationManager.AppSettings["ADPassword"];
using (var context = new DirectoryEntry("LDAP://mydomain.com:389/DC=mydomain,DC=com", ADusername, ADpassword))
using (var search = new DirectorySearcher(context))
{
// create search object which operates on LDAP connection object
// and set search object to only find the user specified
// DirectorySearcher search = new DirectorySearcher(myLdapConnection);
// search.PropertiesToLoad.Add("telephoneNumber");
search.Filter = "(&(objectClass=user)(sAMAccountName=test.test))";
SearchResult r = search.FindOne();
ResultPropertyCollection fields = r.Properties;
foreach (String ldapField in fields.PropertyNames)
{
// cycle through objects in each field e.g. group membership
// (for many fields there will only be one object such as name)
string temp;
// foreach (Object myCollection in fields[ldapField])
// {
// temp = String.Format("{0,-20} : {1}",
// ldapField, myCollection.ToString());
if (ldapField.ToLower() == "telephonenumber")
{
foreach (Object myCollection in fields[ldapField])
{
result.Telephone = myCollection.ToString();
}
}
else if (ldapField.ToLower() == "department")
{
foreach (Object myCollection in fields[ldapField])
{
result.Department = myCollection.ToString();
}
}
// }
}
string output = JsonConvert.SerializeObject(result);
return Json(output,JsonRequestBehavior.AllowGet);
}
}
catch (Exception e)
{
Console.WriteLine("Exception caught:\n\n" + e.ToString());
}
return View(result);
}
now the return JSON will be as follow:-
"\"DisplayName\":null,\"Telephone\":\"123123\",\"Department\":\"IT\",\"Name\":null,\"SamAccountName\":null,\"DistinguishedName\":null,\"UserPrincipalName\":null}"
but in our case we need to return a status code beside the return json data. for example inccase there is an exception we need to return an error code,also if we are able to get the user's info we need to pass succes code 200, and so on.. so how we can achieve this?
you can try something like this
var statusCode=200;
string output = JsonConvert.SerializeObject( new { result = result, StatusCode = statusCode);
but nobody usually do this. When users call API they can check status code that HTTP Client returns, using code like this
var response = await client.GetAsync(api);
//or
var response = await client.PutAsJsonAsync(api, data);
var statusCode = response.StatusCode.ToString();
//or usually
if (response.IsSuccessStatusCode) {...}
else {...}

Get multiple records from a dynamo db table using Global Secondary Index

I have a dynamo db table CustomerOrders with following fields
Primary partition key: CustomerId (Number)
Primary sort key: DepartmentId (Number)
Order (Serialized Json String)
I would like to do a query on multiple customers in one request without using Sort Key (DepartmentId). So I created a Global Secondary Index on CustomerId and would like to use that to query just using the CustomerId. I see documentation only related to BatchGetItemAsync for running batch queries. I don't see a way to set the IndexName on a BatchGetItemRequest. How can that be done?
Below is my code segment so far:
public async Task<List<CustomerOrder>> GetOrdersAsync(List<int> customerIds)
{
var orders = new List<CustomerOrder>();
var tableKeys = new List<Dictionary<string, AttributeValue>>();
foreach (var x in customerIds)
{
tableKeys.Add(new Dictionary<string, AttributeValue> { { "CustomerId", new AttributeValue { N = x.ToString() } } });
}
var dynamoTable = $"CustomerOrders";
var keysAndAttributes = new KeysAndAttributes
{
AttributesToGet = new List<string> { "CustomerId", "DepartmentId", "Order" },
Keys = tableKeys
};
var request = new BatchGetItemRequest
{
ReturnConsumedCapacity = ReturnConsumedCapacity.INDEXES, // Not sure what this does
RequestItems = new Dictionary<string, KeysAndAttributes> { { dynamoTable, keysAndAttributes } }
};
BatchGetItemResponse result;
do
{
result = await dynamoDbClient.BatchGetItemAsync(request); // Exception gets thrown from here
var responses = result.Responses;
foreach (var tableName in responses.Keys)
{
var tableItems = responses[tableName];
foreach (var item in tableItems)
{
orders.Add(new CustomerOrder
{
CustomerId = int.Parse(item["CustomerId"].N),
DepartmentId = int.Parse(item["DepartmentId"].N),
Order = JsonConvert.DeserializeObject<Order>(item["Order"].S)
});
}
}
//  Set RequestItems to the result's UnprocessedKeys and reissue request
request.RequestItems = result.UnprocessedKeys;
} while (result.UnprocessedKeys.Count > 0);
return orders;
}
I am getting The provided key element does not match the schema error with the above code. Please help!
You can't "set the IndexName on a BatchGetItemRequest"
In fact, you can't GetItem() on a GSI/LSI either. GetItem() only works on the table.
And GetItem() always requires the full primary key.
With a partial key, you'd need to perform multiple Query(), one for each hash key.
The GSI isn't doing anything for you. Department as a sort key really isn't doing anything for you either since I assume customerId is unique.
A better structure might have been to have the table defined with only hash key for the primary key;

asp.net web api 2 LINQ to Entities does not recognize the method

I want to invoke method durning mapping my domain class to DTO class but after many tries with LINQ to Entities or LINQ to objects i have failed and i'm getting weird different errors. Actulal error is just a "LINQ to Entities does not recognize the method 'System.String ResizeToLogoImage(System.String)' method, and this method cannot be translated into a store expression.".
Mapping method:
public async Task<SingleCategory> SingleCategoryMapping(EventerApiContext context, int id)
{
var category = await context.Category.Select(c => new SingleCategory
{
CategoryId = c.CategoryId,
CategoryName = c.CategoryName,
CityId = c.CityId,
Events = context.Event.ToList().Where(e=>e.CategoryId == id).Select(e=> new EventForSingleCategory
{
EventId = e.EventId,
EventName = e.EventName,
EventLogo = ImageProcessor.ResizeToLogoImage(e.EventDetail.EventImage.EventImageBase64)
}).ToList()
}).SingleOrDefaultAsync(c => c.CategoryId == id);
return category;
}
Method to be invoked.
public static string ResizeToLogoImage(string base64String)
{
if (base64String == null)
{
return "NULL";
}
var imageToResize = Base64ToImage(base64String);
var resizedImage = ScaleImage(imageToResize, 50, 50);
return ImageToBase64(resizedImage, imageToResize.RawFormat);
}
I know error is appearing during EventLogo property mapping but i have no more idea what to do.
Try to get the data first, before you do the Select statement. I suspect that it is trying to execute ResizeToLogoImage on the database :)

Kendo dropdownlist produces TypeError: n.slice is not a function

Do I need to define the schema? If so, what should that look like? My searches for this seem to only turn up js solutions, I'm looking for the syntax to define it in the editortemplate.
Shared/editortemplate:
#(
Html.Kendo().DropDownList()
.Name("SearchFunction")
.DataTextField("SearchFunctionDesc")
.DataValueField("SearchFunctionCode")
.DataSource(source =>
{
source.Read(read => {
read.Action("GetSearchFunctions", "User");
});
})
.OptionLabel("--Select a Search Function--")
.AutoBind(false)
)
In the controller:
public JsonResult GetSearchFunctions([DataSourceRequest] DataSourceRequest request)
{
var searchFuncs = AdminService.GetSearchFunctions();
DataSourceResult result = searchFuncs.ToDataSourceResult(request);
return Json(result, JsonRequestBehavior.AllowGet);
}
And then my Dapper db query:
var result = new List<SearchFunction>();
using (var conn = new OracleConnection(DatabaseConnectionString))
{
conn.Open();
string query = "select FUNCTION_ID, SEARCH_FUNCTION_CD, " +
"SEARCH_FUNCTION_DESC, IS_ACTIVE " +
"from TBL_SEARCH_FUNCTIONS ";
result = conn.Query(query)
.Select(s => new SearchFunction
{
FunctionId = (int)s.FUNCTION_ID,
SearchFunctionCode = s.SEARCH_FUNCTION_CD,
SearchFunctionDesc = s.SEARCH_FUNCTION_DESC,
Active = s.IS_ACTIVE
}).ToList<SearchFunction>();
conn.Close();
return result;
}
Rewrite your controller method like this:
public JsonResult GetSearchFunctions()
{
var searchFuncs = cmsViewAdminService.GetSearchFunctions();
return Json(searchFuncs, JsonRequestBehavior.AllowGet);
}
That should simplify that method as you don't need the DataSourceRequest (as #CSharper mentioned in the comment). Kendo DropDownLists, unlike the grids, don't require the DataSourceRequest class. This way, you can call the same JsonResult from a jQuery Ajax method if you needed to do so.
You need to return a pure collection from json something that looks like that
{[
{"Id":2,"Name":"some"},
{"Id":3,"Name":"som2"}
]}
If you use ModelView and lambda then you might also try to the code below:
Assume you have a city dropdownlist retrieving data from reference table (populated to CityViewModel):
public JsonResult GetCities()
{
var dataContext = new EFDbContext();
var cities = dataContext.Cities.Select(c => new CityViewModel
{
ID = c.ID,
Name = c.Name
});
return Json(cities, JsonRequestBehavior.AllowGet);
}

LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression

LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression.
public ActionResult PopulateFromDB(string sidx, string sord, int page, int rows)
{
var context = new NerdDinnerEntities();
var jsonData = new
{
total = 1,
page = page,
sord =sord,
records = context.Authors.Count(),
rows = (from n in context.Authors
select new
{ AuthorId = n.AuthorId ,
cell = new string[] { n.AuthorId.ToString(), n.Name.ToString(), n.Location.ToString() }
}).ToList()
};
return Json(jsonData, JsonRequestBehavior.AllowGet);
}
I am writting ToList or Toarray is it not working the error comes :
public ActionResult PopulateFromDB(string sidx, string sord, int page, int rows)
{
var context = new NerdDinnerEntities();
var jsonData = new
{
total = 1,
page = page,
sord =sord,
records = context.Authors.Count(),
rows = (from n in context.Authors
select new
{ AuthorId = n.AuthorId ,
cell = new string[] { n.AuthorId.ToString(), n.Name.ToString(), n.Location.ToString() }
}).ToList()
};
return Json(jsonData,JsonRequestBehavior.AllowGet);
}
From your code I assume your adding a custom property cell for display/storage purposes on the client-side. I would avoid this as your essentially coupling your API call to one particular client. I would suggest you simply return the data required & deal with it at the client-side specifically e.g.
Server
...
select new
{
Id = n.AuthorId,
Name = n.Name,
Location = n.Location
}).ToList();
...
Client
var response = ...
foreach (var author in response)
{
var cell = new string[] { author.Id.ToString(), author.Name, author.Location };
// do something with cell
}
You should try SqlFunctions.StringConvert to convert this, There is no overload for int so you should cast your number to a double or a decimal.
public ActionResult PopulateFromDB(string sidx, string sord, int page, int rows)
{
var context = new NerdDinnerEntities();
var jsonData = new
{
total = 1,
page = page,
sord =sord,
records = context.Authors.Count(),
rows = (from n in context.Authors
select new
{ AuthorId = n.AuthorId ,
cell = new string[] { SqlFunctions.StringConvert((double)n.AuthorId), n.Name, n.Location }
}).ToList()
};
return Json(jsonData,JsonRequestBehavior.AllowGet);
}
You are not using LinqToSql Classes, if you were using that your code should work, but as you mention that you are using LinqToEntity then You should use SqlFunctions.StringConvert to convert to string.

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