I am using below code to get new inserted ID in auto identity column from database.
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It's working fine when I connect my application with MS Sql, but if I connect with Mysql, it always returns 0 (zero).
Is there any other way to get last inserted ID using Entity Framework?
I am using LINQ to store and retrieve data from tables with a clustered index key. However, I also need to know how to obtain an inserted table row identity with an auto-increment Primary key. The "Go To Definition" feature for my data context of dataClassesDataContext provides the following information:
[System.Data.Linq.Mapping.DatabaseAttribute(Name="EFMDB")]
public partial class DataClassesDataContext : System.Data.Linq.DataContext
I am asking for the C# code that is needed in a button click event handler that will insert a row of data in a table named "Fields". It only consists of an auto-incrementing primary key column (FieldID), a string column (Phrase) and a null defaulted variable column.
Here's a simple code snippet where I create a new Entity object and call SaveChanges() to create a new record in the mapped database table.
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What I'm trying to figure out is whether there is a way to derive this new key for my entity, e, from the ObjectContext, m? The reason for this is that the way my actual code is structured, my entity object is already out of scope at the point where I call the SaveChanges() method.
I am trying to get the identity column on which the record is inserted but i couldn't using stored procedure
see
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My Code Using ASP.NET C# i am trying to display the identity in textbox
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I've sucefully created a method to insert values through EF, but i've a question (maybe, a newbie question).
Should i send the values to be inserted as strings to the DAL, and then i create the object there or should i create the object in View Layer and then send him to DAL?
Example 1 (DAL):
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Example 1 (View Layer, on a click button for example):
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Or should i receive the strings in DAL like this: public bool NoticiasInsert(string tituloPT, string tituloEN, string descricaoPT, string descricaoEN)
Then i create the object cdcModel.noticias and set the fields there with the strings values.
What do you advice me to do? I know that both ways works, but i'm trying to develope with better patterns (i don't know if this is the exacly word, sorry my bad english)
cdcModel.noticias campos = new cdcModel.noticias();
campos.tituloPT = "a";
campos.tituloEN = "b";
campos.descricaoPT = "a";
campos.descricaoEN = "a";
if (DAL.NoticiasInsert(campos)
I have generated entity framework designer classes . After Generating the designer what is the most nicest and cleanest way to apply data annotation to the properties there . I have 3 classes there
View 2 RepliesI'm brand new to the Entity Framework and trying to learn all it can offer. I'm currently working my way through the MVC Music Store tutorial which includes the following code:
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I have to change the username column in my database to nullable, which means everywhere in my code, I now have to check username.HasValue and change references to username to username.Value. Is there anything I can do to avoid having to change all the references to username to username.Value?
View 1 RepliesIs there a way to export a EF 4.0 Data Model to EF 3.5?
I looked around and found that we are not able to access EF 4.0 from a ASP.Net 3.5 project here: [URL]
Our project is the 1st to go to .Net 4.0 using Entity Framework and we (the team) were wondering if there was a way for the other projects that "might" need to access our data that are still using the .Net 3.5 framework.
I am developing a asp.net application and i am using SQL Server 2008. I took a IDENTITY column as Record_ID for detail table where i will have trillions of records per year. So just want to ask whats the largest number record id (identity) column can hold and in ASP.NET which data type i should use to handle record id as i am using this id as a reference to update the table data. I don't want to end up being trapped some day.
View 1 Repliesi cannot retrieve the new identity value from an inserted record(via DataAdapter.Update) in my DataRow.
I'm using a strong typed Dataset as DAL. The table i want to update is joinded with other tables in the SelectCommand, hence the designer cannot automatically generate the insert-/update-/delete-commands and also it cannot "Refresh the DataTable" automatically. [URL]
I've tried to set AutoIncrement=true/false on the primary-key's DataColumn but the result is the same: last MAX-ID+1 instead of the actual ID the database generated(SQL-Server 2005 EP; pk datatype:int, Is identity:yes, Identity Increment:1).
This will be the wrong value f.e if another instance of the application inserted a record that the first instance yet not knows and therefore generates an ID that already exists.
To retrieve the new identity from db i've appended following to my insert-command's CommandText:
;SELECT CAST (SCOPE_IDENTITY() AS int) AS newIdRMA
Also i've tried to add an Output-Parameter to it's parameter-collection:
This is part of my code that updates the database and sets the new ID(that doesn't work):
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I need to get the identity (scope_identity) value of the newly inserted record. I don't see a way to do this.
I'm using
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I am new to entity framework , it is really very good , but I want to know what is the difference between using entity framework with stored procedure or without stored procedure , which one the faster and what is the benefits for using stored procedures with entity framework.
View 1 RepliesI have an EDM, it includes the entities extension and history. My goal is to use history to keep track of all the changes made to extension entity. For example, if extension with ID 223 has its property 'Name_Display' changed - I want the history entity to record this.
I'm using ASP.NET with VB.NET. Where in my code do I put the hook to say, "update the history entity" and what should that hook look like?
I have a detailsView that I use for Insert. Once a record is Inserted, I need to get the new idenetity value.
Is there some function that grabs the inserted identity value? Or do I need to query it somehow?
By the way, the reason I'm doing this is the user is inserting a record into a 'general' list that is being applied to a 'specific' list - example, an employee can select a vendor from a list, but the vendor isn't listed so the employee adds the vendor in the vedor list and while the new vendor is inserted, the vendor info is also applied to the new order record.
I have an SQL Server table named "Fields" with an autoincrement identity column "FieldID" as the primary key, an nchar column "Phrase" that textbox entries are to be stored in from a web page, and another column that is defaulted to null. The following is the recommended example on how to use Scope_Identity() to get a newly inserted table row identity value:
//C#
string query = "Insert Into Categories (CategoryName) Values (@CategoryName);" +
"Select Scope_Identity()";
int ID;
string connect = @"Server=.SQLExpress;AttachDbFilename=|DataDirectory|Northwind.mdf;" +
"Database=Northwind;Trusted_Connection=Yes;";
using (SqlConnection conn = new SqlConnection(connect))
{
using (SqlCommand cmd = new SqlCommand(query, conn))
{
cmd.Parameters.AddWithValue("@CategoryName", Category.Text);
conn.Open();
ID = (int)cmd.ExecuteScalar();
}
}
Obviously, this example uses a Categories Table in a Northwind database, which I do not have. So I am confused by how to adapt this example for my application. The following is my data context:
DataClassesDataContext db = new DataClassesDataContext();
Could you explain how I can adapt the example for my "Fields" table in my "EFMDB" database?
This would seem to be quite a trivial task, however I am having trouble retrieving the identity of the record inserted using the detailsview.insert() in the code behind. It would seem that detailsview.DataKey.Value would contain this value, but it is null after the insert is performed.
View 4 RepliesI get an cast exception when i am trying to insert an entity in Entity Framework (using code-first). From this code :
public virtual T Insert(T entity)
{
return Context.Set<T>().Add(entity);
}
The cast exception is like "impossible to cast ...Collection'1(Entity) to type (Entity)" I can't figure out why. I am pretty sure ive done everything right. Post entity
public class Post
{
public long PostId { get; private set; }
public DateTime date { get; set; }
[Required]
public string Subject { get; set; }
public User User { get; set; }
public Category Category { get; set; }
[Required]
public string Body { get; set; }
public virtual ICollection<Tag> Tags { get; private set; }
public Post()
{
Category = new Category();
if (Tags == null)
Tags = new Collection<Tag>();
}................................
I am mapping a stored procedure to an entity by right clicking on the entity (in the .edmx) and selecting "Stored Procedure Mapping." This brings you to a Mapping Details - "Name of Entity" Window that allows you to select the insert, update, and delete stored procedures associated with the Entity. It also maps the stored procedure parameter to the Entity "Property" (Column).
I'm gettin an error "error 2042: Parameter Mapping specified is not valid." The cause of the error is fairly obvious, in the Insert stored procedure that has been selected, a 'CHAR' parameter is being mapped to an Int32 Entity Property. I altered the stored procedure parameter to match the entity, I deleted the stored procedure, readded, and reslected it as the Insert function. I also cleaned, validated, updated model from database. No matter what I do, the parameter list in the mapping details doesn't reflect the change to the stored procedure. It's stuck on a char --> int32 mapping, even though it has been changed, like it's buried deep in meta data some where.
I'm creating a page that uses a MasterPage and a BasePage. I removed the Title="" from the Page declaration, and I added my own title tags to the page Manually. My page looks like this:
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The page displays correctly, and my title tag appears in the header.
However, a few rows below my title tag I see this:
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Why are those being inserted automatically? And how can I get them to stop showing up?
I am trying to add a new entity and have to refernce associated data to add it. I cannot load the Referencetables. Giving "The EntityReference could not be loaded because it is not attached to an ObjectContext." How do i complete this task in Entity Framework 3.5
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I have a stupid problem with the Entity Framework. I get the following Exception:
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I have an entity with a 4 fields representing the primary key. I copy it via serialization (works fine). I set the old entity to not valid (Datefield set to a date in the past, this field is part of the PK) and set the copied entity to DateTime.Now.Date. When I call context.AddObject I get the Exception above. I tried copying the entity via reflection but the entity has 3-4 references. And when copied, I get another Exception before even Adding the entity to the context. I also tried setting newObj.EntityKey = null and reset all the fields neccessary for the PK. I just want a whole copy of an entity with a different primary key (and some other fields changed too) and Create it in the database.
The only thing I can think to do is to call GetByExample(entityJustInserted) and pick the one with the highest ID. Not great...anyone got a better way?
View 1 RepliesI'm writing a custom .NET MembershipProvider (not the built in one) and trying to update using Entity Framework. But of course i have no access to (Try)UpdateModel. How can i update it?
View 3 RepliesI have an Events table and an InstallmentPlans table. The relationship is 0..1 : an Event can have 0 or 1 Installment plans. If I want to remove the existing InstallmentPlan for an event, how do I do this? Setting it to null doesn't seem to work:
_event.InstallmentPlan = null;