Can't insert data in a table using entity framework - linq

I'm working with the Entity Framework and I'm having a problem:
When I try to insert some data in a table it tells me that it's violating integrity of reference but the other table is normally populated and has the value i'm trying to insert.
Pedido pedido = new Pedido();
pedido.Data = DateTime.Now;
db.AddToPedido(pedido);
db.SaveChanges();
EntityKey chave = db.CreateEntityKey("Pedido", pedido);
Itens_Pedido item = new Itens_Pedido();
item.Pedido_Id = Convert.ToInt32(chave.EntityKeyValues.First().Value);
item.Carta_Id = Convert.ToInt32(Request.QueryString["Id"].ToString());
item.Quantidade = 1;
item.Foil = "N";
db.AddToItens_Pedido(item);
db.SaveChanges();

I think you need to do your foriegn keys more like:
item.PedidoReference.EntityKey = new System.Data.EntityKey("[EntityNamespace].Pedido", "Pedido_Id", idValue);
where [EntityNamespace] is the namespace your entities live in.

Related

ef6 linq method returning $ref for nested entries in query

my linq method system from EF6 is returning $ref when I monitor results in fiddler. If I watch the local window in my webapi everything is populated correctly, but not in the actual results that are returned. It only affects the nested entries. anyone know what I am doing wrong? (I created models from database in EF6)
var student = dbEF.Accounts
.Where(x => x.AccountNumber == acctNum)
.Select(x => new DTOCrmDetails()
{
AccountNumber = x.AccountNumber,
CommissionId = x.CommissionId,
Commission = x.Commission,
ManagerID = x.ManagerID,
ManagerName = x.Manager.ManagerName,
Manager = x.Manager,
Employees = x.Manager.Employees,
WireInstructionsUSD = x.Manager.WireInstructionsUSDs
//Mapping_ManagersExecutingBrokers = x.Manager.Mapping_ManagersExecutingBrokers
}).FirstOrDefault();
return student;
these are my settings.
var json = config.Formatters.JsonFormatter; json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects; config.Formatters.Remove(config.Formatters.XmlFormatter); config.Formatters.JsonFormatter.SerializerSettings.Formatting = Newtonsoft.Json.Formatting.Indented; config.Formatters.JsonFormatter.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
You need to disable your lazy loading in the entity framework dbcontext.
something like this way:
dbEF.Configuration.LazyLoadingEnabled = false;

Linq/Entity Framework syntax for adding a record to a database

I need to add a record to a database using the Entity Framework. Since I'm brand new to using this syntax I am not sure how to properly write the code (Below is my best guess).
First, the agent must have their info inserted into the Agent table. This table produces a self-incrementing primary key known as a SymNumber. I then need to take that SymNumber and use it as a primary key for an insert into the AgentIdentification table.
I have run this code a couple of times, and I do not come up with an error, however since I am using a unit test to test the code I cannot tell for sure if the agent is being added properly. Secondly, I know for a fact that I am not correctly grabbing the SymNumber as generated by the Agent table after the first insert. The SymNumber is an int value in the Linq code set to 0, and this does not change during the AgentIdentification insert.
Any help would be greatly appreciated!
AgentResourcesEntities _db = new AgentResourcesEntities();
try
{
Agent agent = new Agent();
agent.EntityType = "P";
agent.FirstName = agentNewTraining.FirstName;
agent.LastName = agentNewTraining.LastName;
agent.LastChangeOperator = agentNewTraining.Requestor;
agent.LastChangeDate = DateTime.Now;
if (!String.IsNullOrEmpty(agentNewTraining.NameSuffix)) agent.NameSuffix = agentNewTraining.NameSuffix;
_db.Agent.AddObject(agent);
AgentIdentification agentIdentification = new AgentIdentification();
agentIdentification.SymNumber = agent.SymNumber;
agentIdentification.ReferenceType = "S";
agentIdentification.DummyReference = 0;
agentIdentification.LastChangeOperator = agentNewTraining.Requestor;
agentIdentification.LastChangeDate = DateTime.Now;
_db.AgentIdentification.AddObject(agentIdentification);
return true;
}
catch (Exception)
{
return false;
}
First you need to call
_db.SaveChanges();
to get your changed persisted.
But if you want also synchronize (get the new generated value) your agent.SymNumber you will need to call SaveChanges() right after adding it to context.
So the code will be like:
/// ...... ////
_db.Agent.AddObject(agent);
_db.SaveChanges();
AgentIdentification agentIdentification = new AgentIdentification();
agentIdentification.SymNumber = agent.SymNumber; // sym number is now synchronized from DB
///...../////
_db.AgentIdentification.AddObject(agentIdentification);
_db.SaveChanges();
But if SymNumber is foreign key so the AgentIdentification has could have reference to some Agent instance, you can just tie those instances with that reference and would not need to call that additional SaveChanges() in the middle.
Call _db.SaveChanges() after inserting.

why EF tries to add new record instead of edit?

I have the following code:
var currentUser = (from i in _dbContext.Users
where i.FirstName == user.FirstName && i.LastName == user.LastName
&& i.Title == user.Title && i.Company == user.Company
select i).FirstOrDefault();
currentUser.Company = user.Company;
currentUser.CompanyUrl = user.CompanyUrl;
currentUser.Country = user.Country;
_dbContext.SaveChanges();
but I got an error
{"Violation of UNIQUE KEY constraint 'IX_Users'. Cannot insert
duplicate key in object 'dbo.Users'. The duplicate key value is (a8,
b8, c8).\r\nThe statement has been terminated."}
so, it says that EF tries to add new record instead of edit current. Why?
I think the problem will be combining user and currentUser. It most probably updates your currentUser but in the same time inserts user. The reason can be this:
currentUser.Company = user.Company;
If company has Users navigation property and if you are using POCO template this will connect both Company and user as new entities to the context.
Try this:
var currentUser = ...;
var company = new Company { Id = user.Company.Id };
_dbContext.Companies.Attach(company);
currentUser.Company = company;
...
_dbContext.SaveChanges();

Retrieving related entities using RetrieveMultipleRequest

I have an entity called Invoice and an entity called InvoiceItem.
There is a one to many relationship called new_invoice_invoiceitem.
There is a LookupAttribute in InvoiceItem called new_parent_invoice_invoiceitem.
I am trying to retrieve the InvoiceItems that are related to the Invoice with a particular ID using the following code:
QueryExpression query = new QueryExpression();
query.EntityName = "new_invoiceitem";
query.ColumnSet = new AllColumns();
ConditionExpression condition = new ConditionExpression();
condition.AttributeName = "new_parent_invoice_invoiceitem";
condition.Values = new object [] { new Guid("fe1009cc-e034-49d5-bc59-ab4c3091a6f9") };
condition.Operator = ConditionOperator.Equal;
FilterExpression filter = new FilterExpression();
filter.AddCondition(condition);
query.Criteria = filter;
RetrieveMultipleRequest request = new RetrieveMultipleRequest();
request.Query = query;
RetrieveMultipleResponse response = (RetrieveMultipleResponse)crmService.Execute(request);
BusinessEntityCollection bec = response.BusinessEntityCollection;
The code runs without errors but the BusinessEntityCollection is always empty even though there are records in Dynamics.
Any idea what I'm doing wrong?
Thanks,
David
Try setting request.ReturnDynamicEntities = true

Auditing in Entity Framework

After going through Entity Framework I have a couple of questions on implementing auditing in Entity Framework.
I want to store each column values that is created or updated to a different audit table.
Right now I am calling SaveChanges(false) to save the records in the DB(still the changes in context is not reset). Then get the added | modified records and loop through the GetObjectStateEntries. But don't know how to get the values of the columns where their values are filled by stored proc. ie, createdate, modifieddate etc.
Below is the sample code I am working on it.
// Get the changed entires( ie, records)
IEnumerable<ObjectStateEntry> changes = context.ObjectStateManager.GetObjectStateEntries(EntityState.Modified);
// Iterate each ObjectStateEntry( for each record in the update/modified collection)
foreach (ObjectStateEntry entry in changes)
{
// Iterate the columns in each record and get thier old and new value respectively
foreach (var columnName in entry.GetModifiedProperties())
{
string oldValue = entry.OriginalValues[columnName].ToString();
string newValue = entry.CurrentValues[columnName].ToString();
// Do Some Auditing by sending entityname, columnname, oldvalue, newvalue
}
}
changes = context.ObjectStateManager.GetObjectStateEntries(EntityState.Added);
foreach (ObjectStateEntry entry in changes)
{
if (entry.IsRelationship) continue;
var columnNames = (from p in entry.EntitySet.ElementType.Members
select p.Name).ToList();
foreach (var columnName in columnNames)
{
string newValue = entry.CurrentValues[columnName].ToString();
// Do Some Auditing by sending entityname, columnname, value
}
}
Here you have two basic options:
Do it at the database level
Do it in the c# code
Doing it at the data base level, means using triggers. In that case there is no difference if you are using enterprise library or another data access technology.
To do it in the C# code you would add a log table to your datamodel, and write the changes to the log table. When you do a save changes both the changes to the data and the information which you wrote to the log table would be saved.
Are you inserting the new record using a stored proc? If not (i.e. you are newing up an object, setting values, inserting on submit and then saving changes the new object id will be automatically loaded into the id property of the object you created. If you are using a stored proc to do the insert then you need to return the ##IDENTITY from the proc as a return value.
EX:
StoreDateContext db = new StoreDataContext(connString);
Product p = new Product();
p.Name = "Hello Kitty Back Scratcher";
p.CategoryId = 5;
db.Products.Add(p);
try
{
db.SaveChanges();
//p.Id is now set
return p.Id;
}
finally
{
db.Dispose;
}

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