I got the above error while trying to insert values to the table 'T_PreviewDetails' through below code.
T_PreviewDetails objprevdet = new T_PreviewDetails();
objprevdet.Title = "preview";
objprevdet.Preview_ID = objprev.ID;
objprevdet.SelectionListDetails_ID = objSelectListDetails.ID;
objprevdet.PreviewStatus_ID = 2;
context.T_PreviewDetails.Add(objprevdet);
context.SaveChanges();
But direct inserting values to the database works fine.Also in 'T_PreviewDetails.cs'
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] is entered.
Related
I did raw SQL query below to select only certain fields from a table.
{
List<CustEmpVM> CustomerVMlist = new List<CustEmpVM>();
var cid = db.Customers.SqlQuery("select SchedDate from Customer where CustID = '#id'").ToList<Customer>();
}
But i keep getting the error of:
System.Data.Entity.Core.EntityCommandExecutionException occurred in EntityFramework.SqlServer.dll but was not handled in user code
Additional information: The data reader is incompatible with the specified ALFHomeMovers.Customer. A member of the type, CustID, does not have a corresponding column in the data reader with the same name.
The exception message is pretty straightforward: the query expected to return full entity of Customer table but only SchedDate column returned, hence EF cannot done mapping other omitted columns including CustID.
Assuming Customers is a DbSet<Customer>, try return all fields from Customer instead:
// don't forget to include SqlParameter
var cid = db.Customers.SqlQuery("SELECT * FROM Customer WHERE CustID = #id",
new SqlParameter("id", "[customer_id]")).ToList();
If you want just returning SchedDate column, materialize query results and use Select afterwards:
var cid = db.Customers.SqlQuery("SELECT * FROM Customer WHERE CustID = #id",
new SqlParameter("id", "[customer_id]"))
.AsEnumerable().Select(x => x.SchedDate).ToList();
NB: I think you can construct LINQ based from the SELECT query above:
var cid = (from c in db.Customers
where c.CustID == "[customer_id]"
select c.SchedDate).ToList();
Similar issue:
The data reader is incompatible with the specified Entity Framework
Use below query instead of raw query:
{
List<CustEmpVM> CustomerVMlist = new List<CustEmpVM>();
var cid = db.Customers.Where(w=>w.Id == YOURCUSTOMERID).Select(s=>new Customer{SchedDate = s.SchedDate }).ToList();
}
It will give compile time error rather than run time error.
I am trying to add a new record to a table i my database. The code I have adds the record to the table but also throws an exception "System.Data.SqlClient.SqlException: Violation of PRIMARY KEY constraint 'PK_COURSE_TAKEN'. Cannot insert duplicate key in object 'dbo.COURSE_TAKEN'. The duplicate key value is (000160228, HIS 155).". Why is it trying to add the record twice? I know for 100% certainty that there is no existing record already present before I try to add it. Below is my code for adding the record:
using (KuPlanEntities db = new KuPlanEntities())
{
var courseTake = new COURSE_TAKEN();
courseTake.Id = "000160228";
courseTake.courseAbNum = courseAbNum;
courseTake.status = status;
courseTake.grade = grade;
db.COURSE_TAKEN.Add(courseTake);
db.SaveChanges();
}
I am trying to extract the [key] value from a table.
This is for a logging method which looks like this:
private List<Log> GetAuditRecordsForChange(DbEntityEntry dbEntry, string userId)
{
List<Log> result = new List<Log>();
DateTime changeTime = DateTime.Now;
// Get the Table() attribute, if one exists
TableAttribute tableAttr = dbEntry.Entity.GetType().GetCustomAttributes(typeof(TableAttribute), false).SingleOrDefault() as TableAttribute;
// Get table name (if it has a Table attribute, use that, otherwise get the pluralized name)
string tableName = tableAttr != null ? tableAttr.Name : dbEntry.Entity.GetType().Name;
// Get primary key value
string keyName = dbEntry.Entity.GetType().GetProperties().Single(p => p.GetCustomAttributes(typeof(KeyAttribute), false).Count() > 0).Name;
if (dbEntry.State == EntityState.Added)
{
result.Add(new Log()
{
LogID = Guid.NewGuid(),
EventType = "A", // Added
TableName = tableName,
RecordID = dbEntry.CurrentValues.GetValue<object>(keyName).ToString(),
ColumnName = "*ALL",
NewValue = (dbEntry.CurrentValues.ToObject() is IDescribableEntity) ? (dbEntry.CurrentValues.ToObject() as IDescribableEntity).Describe() : dbEntry.CurrentValues.ToObject().ToString(),
Created_by = userId,
Created_date = changeTime
}
);
}
The problem is to get the RecordID when a Record is added, when it get deleted or modified it works. (The code to get it is the same)
When I debug I also see that it has the KeyAttribute in the CustomAttributes base but not sure why it always shows up as 0.
I can debug more if needed
After savechanges you can fetch the newly created key. (Guess the key is generated automatically inserting a new record).
for me you have several solutions.
first solution:
enlist added entity from the context
SaveChanges
enumerate the enlisted entities to add log
SaveChanges
the problem (or not) here is that the business and the logging are not in the same transaction.
antother problem, depending on the implementation, is to prevent loging of log of log of log... This can be donne by filtering entities by typeName for example.
other solution:
add and ICollection<Log> to your entities.
the problem here is to unify the logs:
inheritance of entity, or
several log tables + a view
...
other solution
use trigger at database level
other solution
..., use cdc if you have Sql Server Enterprise Edition
I am calling a web service from my MVC project and if it is successful then it returns process complete. This result, I am storing in variable called y.
var y = Here pass required parameters and if it is successfull store result in y
when I put breakpoint here and if process complete, I can see result in var y.
So if process complete I need to update my table. For this can I do like this ?
if( y = "Process complete")
{
update table code here
}
and I don't know how to update table in Entity Framework. Here I need to update table called table1 and set column2 = 1, column 3 = value of column 4 where column 1 = value of column 1.
What I know for this is :
UPDATE tableName
SET column2 = 1, column3 = context.FirstOrDefault().column4
WHERE column1 = context.FirstOrDefault(). column1
Update :
Hi i got to know how to write code to update table.But when i put break-point and come to savechanges method i am getting Property export is part of the objects key information and cannot be modified error.
This is the code i am using to update my table :
var rec = (from s in geton.table_1
where s.on_id == geton.table_1.FirstOrDefault().on_id
select s).FirstOrDefault();
rec.export = 1;
rec.on_date = geton.table_1.FirstOrDefault().on_date;
geton.SaveChanges();
A new entity can be added to the context by calling the Add method on DbSet. This puts the entity into the Added state, meaning that it will be inserted into the database the next time that SaveChanges is called.
For example:
using (var context = new YourContext())
{
var record = new TypeName { PropertyName = "Value" };
context.EntityName.Add(record );
context.SaveChanges();
}
For More Info :
http://msdn.microsoft.com/en-us/library/bb336792.aspx
http://msdn.microsoft.com/en-us/data/jj592676.aspx
http://www.entityframeworktutorial.net/significance-of-savechanges.aspx
Hi i got to know how to write code to update table.But when i put break-point and come to savechanges method i am getting Property export is part of the objects key information and cannot be modified error.
That sounds more like a Key error. Are you sure you have put a primary key on that table?
If not then EF just uses the whole table as the key essentially
I have a rather simple scenario where I have two tables in which I want to add data. They are managed with primary key/foreign key. I want to add new data into TABLE A and then retrieve the Id and insert into TABLE B.
I can certainly do it with a stored procedure, but I'm looking at trying to do it using Linq.
What is the best approach ?
I can certainly get the ID and do two separate inserts but that doesn't certainly seem to be a very good way of doing things.
db.Table.InsertOnSubmit(dbObject);
db.SubmitChanges();
Int32 id = dbOject.Id;
//Rest of the code
Any way to elegantly do this?
Do you have the relationship defined between the 2 tables in the object relational designed? If so, you can have linq take care of assigning the ID property of the second table automatically.
Example...
Table A – Order
OrderId
OrderDate
Table B – Order Item
OrderItemId
OrderId
ItemId
Code (Using LINQ-to-SQL):
Order order = new Order();
Order.OrderDate = DateTime.Now();
dataContext.InsertOnSubmit(order);
OrderItem item1 = new OrderItem();
Item1.ItemId = 123;
//Note: We set the Order property, which is an Order object
// We do not set the OrderId property
// LINQ will know to use the Id that is assigned from the order above
Item1.Order = order;
dataContext.InsertOnSubmit(item1);
dataContext.SubmitChanges();
hi i insert data into three table using this code
Product_Table AddProducttbl = new Product_Table();
Product_Company Companytbl = new Product_Company();
Product_Category Categorytbl = new Product_Category();
// genrate product id's
long Productid = (from p in Accountdc.Product_Tables
select p.Product_ID ).FirstOrDefault();
if (Productid == 0)
Productid++;
else
Productid = (from lng in Accountdc.Product_Tables
select lng.Product_ID ).Max() + 1;
try
{
AddProducttbl.Product_ID = Productid;
AddProducttbl.Product_Name = Request.Form["ProductName"];
AddProducttbl.Reorder_Label = Request.Form["ReorderLevel"];
AddProducttbl.Unit = Convert.ToDecimal(Request.Form["Unit"]);
AddProducttbl.Selling_Price = Convert.ToDecimal(Request.Form["Selling_Price"]);
AddProducttbl.MRP = Convert.ToDecimal(Request.Form["MRP"]);
// Accountdc.Product_Tables.InsertOnSubmit(AddProducttbl );
// genrate category id's
long Companyid = (from c in Accountdc.Product_Companies
select c.Product_Company_ID).FirstOrDefault();
if (Companyid == 0)
Companyid++;
else
Companyid = (from Ct in Accountdc.Product_Companies
select Ct.Product_Company_ID).Max() + 1;
Companytbl.Product_Company_ID = Companyid;
Companytbl.Product_Company_Name = Request.Form["Company"];
AddProducttbl.Product_Company = Companytbl;
//Genrate Category id's
long Categoryid = (from ct in Accountdc.Product_Categories
select ct.Product_Category_ID).FirstOrDefault();
if (Categoryid == 0)
Categoryid++;
else
Categoryid = (from Ct in Accountdc.Product_Categories
select Ct.Product_Category_ID).Max() + 1;
Categorytbl.Product_Category_ID = Categoryid;
Categorytbl.Product_Category_Name = Request.Form["Category"];
AddProducttbl.Product_Category = Categorytbl;
Accountdc.Product_Tables.InsertOnSubmit(AddProducttbl);
Accountdc.SubmitChanges();
}
catch
{
ViewData["submit Error"] = "No Product Submit";
}