Update Record in Entity Framework

Entity Framework is a popular Object Relational Mapping (ORM) framework used in .NET programming languages. It simplifies the process of accessing and manipulating data from a database. In this article, we’ll focus on updating records in Entity Framework.

Updating Records in Entity Framework

Updating records with Entity Framework involves four fundamental steps. They are:

  1. Retrieving the entity to be updated

  2. Modifying the entity properties

  3. Marking the entity as modified

  4. Saving the changes to the database

Now, let’s look at each step in detail.

Retrieving the Entity to be Updated

The first step in updating a record is to retrieve it from the database. This can be done in various ways. However, the most common way is to use the Find() method. This method accepts the primary key value(s) of the entity and returns the corresponding entity from the database.

For example, if we have a Customer entity with a primary key of CustomerId, and we want to update the customer with an id of 1, we can retrieve the entity with the following code:

“`csharp
var customer = context.Customers.Find(1);
“`

Here, context refers to the database context instance that represents a connection to the database. The Customers property represents the table that contains the Customer entities.

Modifying the Entity Properties

After retrieving the entity, we can modify its properties as required. We can do this using standard property assignment syntax in C#.

“`csharp
customer.Name = “John Doe”;
customer.Email = “johndoe@example.com”;
“`

Marking the Entity as Modified

After modifying the entity properties, we need to mark the entity as modified so that Entity Framework knows that changes have been made to it. This can be done using the Entry() method on the database context instance.

“`csharp
context.Entry(customer).State = EntityState.Modified;
“`

The Entry() method returns an object that represents the specified entity in the database. We then set the State property of the object to EntityState.Modified to mark the entity as modified.

Saving the Changes to the Database

The final step in updating a record is to save the changes to the database. This can be done by calling the SaveChanges() method on the database context instance.

“`csharp
context.SaveChanges();
“`

This method applies all changes made to the entities in the database context to the actual database.

FAQs

Can I update multiple records at once?

Yes, you can update multiple records at once using Entity Framework. This can be done using the UpdateRange() method on the DbSet class. This method accepts an IEnumerable of entities to be updated and updates them all at once.

“`csharp
var customers = context.Customers.Where(c => c.City == “London”).ToList();
foreach(var customer in customers)
{
customer.City = “Paris”;
context.Entry(customer).State = EntityState.Modified;
}
context.SaveChanges();
“`

Can I selectively update only some properties of an entity?

Yes, you can selectively update only some properties of an entity. You can do this by setting the specific properties of the entity you want to update and then marking the entity as modified as shown below:

“`csharp
var customer = context.Customers.Find(1);
customer.Name = “John Doe”;
context.Entry(customer).Property(c => c.Name).IsModified = true;
context.SaveChanges();
“`

In the above code, we selectively update only the Name property of the Customer entity.

Can I update records in a transaction?

Yes, you can update records in a transaction using Entity Framework’s transactional processing capabilities. You can use the TransactionScope class to write transactional code as shown below:

“`csharp
using (var scope = new TransactionScope())
{
var customer1 = context.Customers.Find(1);
var customer2 = context.Customers.Find(2);
customer1.City = “Paris”;
customer2.City = “Paris”;
context.SaveChanges();
scope.Complete();
}
“`

The code above wraps the update operation in a transaction using the TransactionScope class. The Complete() method is called on the transaction scope object to commit the transaction.

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