I am using Entity Framework (v6.1) with the Database First method. I have created my EDMX file and it references a stored procedure I selected while creating the EDMX via the EF wizard. My question is how do I use what the stored procedure returns?
Below is my dbContext and the name of the stored procedure GetHtmlContent. The stored procedure takes contentId as an integer parameter.
Here is the SQL of the stored procedure GetHtmlContent ..
SELECT
HtmlContent.contentId,
HtmlContent.[Name] AS 'Name',
HtmlContent.HTML AS 'HTML',
HtmlContentCategory.CategoryTitle
FROM HtmlContent
LEFT JOIN HtmlContentCategory ON HtmlContent.CategoryID = HtmlContentCategory.HtmlContentCategoryID
WHERE HtmlContent.ContentId= #ContentId
Below is what I get when I hover over the stored procedure method contained within the dataContext to see what is returned.
System.Data.Entity.Core.Objects.ObjectResults<GetHtmlContent_Result> dbContext.GetHtmlContent(contentId)
This is where I am getting confused ...
Is the <GetHtmlContent_Result> a type representing the dataset returned by the stored procedure?
What is System.Data.Entity.Core.Objects.ObjectResults?
Since I am accepting a collection of records from the stored procedure do I need to create a class to hold the results of the stored procedure?
Is the a type representing the dataset returned by the stored procedure?
GetHtmlContent_Result is representing each record that is produced by stored procedure.
HtmlContent.contentId,
HtmlContent.[Name] AS 'Name',
HtmlContent.HTML AS 'HTML',
HtmlContentCategory.CategoryTitle
What is System.Data.Entity.Core.Objects.ObjectResults?
The ObjectResult is an enumerable collection class, but it is a
forward-only collection so once it has been enumerated, you cannot
enumerate it again. For example, if you call ToList on the result,
e.g., GetDetailsForOrder(3).ToList(), then you cannot subsequently
provoke another enumeration by calling ToList again, binding the
results to a control or executing a foreach over the results. - MSDN
Since I am accepting a collection of records from the stored procedure do I need to create a class to hold the results of the stored procedure?
It's just like other entities that represent tables in the database, a POCO. You can use it directly.
Related
I have a database first setup in .net6
I need to call a stored proc (Lets say it is called GetMyData)
The stored proc is going to return 5 columns from various tables and so does not map to a current entity model.
The only things I can find is to use the context model to return a stored proc result but that will not work as the result set does not map to an existing model. Or a convoluted ADO.Net style call that looks horrific and needs lots of code.
Is there a simple way to call a stored proc that returns various columns from many tables?
I have a stored procedure that updates a date column in a table in MS SQL Server database. This stored procedure does not have any complex logic. It does a simple update on the date column with the value passed in its input parameter. This stored procedure does not return any result set upon successful execution but returns a result set with a few columns with names ErrorNumber, ErrorSeverity etc., when the stored procedure execution throws an exception from the try..catch exception handling block.
I am using DB First entity approach; I have updated Entity Data Model for this stored procedure from my asp.net MVC web application. Entity framework designer generated a complex type for the return type on this stored procedure with a property for each of the columns in the columns list returned in the catch block. When I invoked the stored procedure from asp.net MVC application with valid input parameters, I encountered the "Datareader is incompatible exception". I know this exception is triggered by entity framework because the stored procedure execution does not return a result set and the framework is expecting a column to be returned back with the name "ErrorNumber". I invoked the stored procedure directly with the db context instance with required valid parameter values.
for example db.UpdateProcedure(dueDate). I did not use a data table to load the data from the data reader. I know loading the result set into a data table will not cause this exception.
After making a minor change to the stored procedure to return ##rowcount on successful execution, the application did not throw this exception upon this stored procedure invocation.
I am wondering if there is a better way to deal with this situation without updating the stored procedure to return ##rowcount.
I am using the designer generated entity model from the database; I did not make any manual changes to the schema after auto-generation of the entity model. To be honest, I don't like doing manual changes to the schema once it is auto-generated.
Is there anything I am missing during the entity schema update for this stored procedure to have correct complex type generated when the model is updated from entity designer?
Is the stored procedure returning a result set upon exception occurrence and not returning any result upon successful execution causing any problem to the process that updates entity schema?
Your help is much appreciated.
Thank you in advance.
Is it possible to define an Entity that is not mapped to a table in database and to use a stored procedure to return the entries?
I found that I can use "Ignore" so the table in database is not created for an Entity, but how can I set a stored procedure to populate data for this entity?
Note: I am using code first.
Thanks.
You could create a normal model class that's not referenced by your database context. The model class should contain the properties you'll be returning from your stored proc. Then use
context.Database.ExecuteSqlCommand("storedProc", params)
// OR
context.Database.SqlQuery<YourEntityType>("storedProc",params);
Hi I have a stored procedure which returns result of some fields of multiple tables . can i map the result to associated tables (without using complex types)?
thanks.
Out of the box implementation allows you mapping only to flat structures. So either your stored procedures returns single mapped entity type or you need a complex / custom type. It doesn't allow mapping to relations.
I've created a function import that returns the results of a stored proceedure as one of my entities. however I can't seem to traverse my through navigation properties to access the data in other entities. I know that you can use include() for objectQueries but can't find anything that will force the EF to load my relations for entity results of function imports.
Any ideas??
Thanks in advance.
This is not possible in EF 1.0
The reason is that EF will consider stored procedure values to be just values and not navigation properites.
For example, Employee entity has multiple Order entities. In Order you have a property called EmployeeID. When the database fills your query using include statements, it creates 1 projection query in SQL to populate all of the Order data that a particular Employee could have.
So if I said
var employee = context.Employees.Include("Orders").Where(e => e.ID == 1).First();
var orders = employee.Orders;
The SQL for the first query will create a projection query which will contain orders where the EmployeeID = 1.
Now when your stored procedure runs, this can do any code behind the scenes (in otherwords it can return any set of data). So when SQL runs the stored procedure, it just runs the code in that stored procedure and does not have any knowledge that EmployeeID on Order is an FK to that property. Additionally, if your stored procedure returns an Employee entity, then you are looking at another scenario where you will not even have an OrderID to pursue.
To work around this though, you can setup your query in EF using Include statements that can mirror any stored procedure. If you use the proper mix of .Select and .Include statements you should be able to do the same thing.