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How can I update multiple rows at a time in SQL?

How can I update multiple rows at a time in SQL?

UPDATE config SET t1. config_value = ‘value’ , t2. config_value = ‘value2’ WHERE t1. config_name = ‘name1’ AND t2.

How do you update multiple rows in EF core?

To update multiple rows in Entity Framework earlier we used to loop through the collection and set updated value for each row then finally call save changes.

How do I insert multiple rows in Entity Framework?

You can add multiple records or multiple objects using the AddRange method of DbSet as shown in the following code. The code creates a list of department objects and inserts two new departments to the list. We add the list to the context using the AddRange method.

How do I update a table in EF core?

To update an entity with Entity Framework Core, this is the logical process:

  1. Create instance for DbContext class.
  2. Retrieve entity by key.
  3. Make changes on entity’s properties.
  4. Save changes.

What is Entitystate detached?

Detached. 1. The object exists but is not being tracked. An entity is in this state immediately after it has been created and before it is added to the object context.

How do I update a column in Entity Framework?

  1. load the object based on the userId provided – the entire object gets loaded.
  2. update the password field.
  3. save the object back using the context’s .SaveChanges() method.

How do you enter data in code first approach?


  1. connectionString=”Data Source=WIN-B4KJ8JI75VF;Initial Catalog=EmployeeDB;Integrated Security=true”
  2. providerName=”System.Data.SqlClient”/>

How do I seed data in EF core?

Data seeding is the process of populating a database with an initial set of data….There are several ways this can be accomplished in EF Core:

  1. Model seed data.
  2. Manual migration customization.
  3. Custom initialization logic.

What does DbContext Savechanges return?

Returns. The number of state entries written to the underlying database. This can include state entries for entities and/or relationships.

What is DB SaveChanges ()?

db. SaveChanges() is not part of ASP.NET MVC – it’s part of Entity Framework which is a set of Object-Relational-Mapping (ORM) tools for the . NET Framework. All this method does is persist (save) data in some of your classes (entities) into a database.

When should I call SaveChanges?

All operations will be executed within a single transaction (for a single saveChanges call) which means that either all or none will be propogated to the database at once. Before calling save changes, the changes are applied to your local tracking graph but not to the database itself until savechanges is called.

What all operations could be done using DB context instance?

You can use a DbContext associated to a model to:

  • Write and execute queries.
  • Materialize query results as entity objects.
  • Track changes that are made to those objects.
  • Persist object changes back on the database.
  • Bind objects in memory to UI controls.

What is DbContext in EF core?

An instance of DbContext represents a session with the database which can be used to query and save instances of your entities to a database. DbContext is a combination of the Unit Of Work and Repository patterns. DbContext in EF Core allows us to perform following tasks: Querying database. Saving data to the database.

What is DbContext set?

Set(Type) Returns a non-generic DbSet instance for access to entities of the given type in the context and the underlying store.

How can create DbContext file in MVC?

In this tutorial, you:

  1. Create an MVC web app.
  2. Set up the site style.
  3. Install Entity Framework 6.
  4. Create the data model.
  5. Create the database context.
  6. Initialize DB with test data.
  7. Set up EF 6 to use LocalDB.
  8. Create controller and views.

Why is DbSet virtual?

While the virtual keyword on the derived DbContext class (virtual DbSet<>) is used for testing purpose (mocking the DbSet property), virtual keyword in this case is not related to lazy loading.

Why navigation properties are virtual?

1 Answer. If you define your navigation property virtual , Entity Framework will at runtime create a new class (dynamic proxy) derived from your class and uses it instead of your original class. This new dynamically created class contains logic to load the navigation property when accessed for the first time.

What is virtual keyword in Entity Framework?

C# virtual keyword is used to create virtual methods in C#. A virtual method is created in the base class that can be overriden in the derived class. We create a virtual method in the base class using the virtual keyword and that method is overriden in the derived class using the override keyword.

What does virtual mean in Entity Framework?

The Entity Framework requires your navigation properties to be marked as virtual so that lazy loading and efficient change tracking are supported. So your POCO is acting as a base type for the Entity Framework’s dynamically created subclasses. That’s what I meant by “create a proxy around”.

What is ICollection in Entity Framework?

Collections. ICollection interface inherits from System. Collections. Collections. ICollection interface represents a finite dynamic collection that are changeable, which means that exist items can be removed from the collection and new items can be added to the same collection.

How can I UPDATE multiple rows at a time in SQL?

How can I UPDATE multiple rows at a time in SQL?

To update multiple columns use the SET clause to specify additional columns. Just like with the single columns you specify a column and its new value, then another set of column and values.

How do you write multiple UPDATE statements in SQL?

Yes, you could add all the single-line-Update-statements in one query like you are doing. Other than that, running multiple updates is the way to go. I think the best way is to import the Excel sheet into a table in your SQL database.

How can we update multiple rows in a single update statement?

In order to make multiple updates, you can use a CASE block in SQL combined with an appropriate WHERE clause to select the appropriate rows and set the different values. Do NOT forget the WHERE clause otherwise all other values will be set to NULL.

How to update from select statement in SQL Server?

— Query to UPDATE from SELECT Statement in SQL Server USE [SQL Tutorial] GO MERGE INTO [EmployeeDuplicates] AS [EmpDup] USING ( SELECT EmpID, [FirstName], [LastName], [YearlyIncome] FROM [Employee] ) [Emp] ON [EmpDup].EmpID = [Emp].EmpID WHEN MATCHED THEN UPDATE SET [EmpDup]. [FirstName] = [Emp]. [FirstName], [EmpDup].

How to update multiple columns in a table?

PICTURE column was updated. 2. Update data in two columns in table A based on a common column in table B. If you need to update multiple columns simultaneously, use comma to separate each column after the SET keyword. Both DESCRIPTION and PICTURE column were updated. 3. Conditionally update data in table A based on a common column in table B.

Can a subquery be used in an UPDATE statement?

The table has been replaced with the SELECT statement that only shows two columns of the table. Using a subquery in an UPDATE statement can be a good way to improve the maintainability of your queries. It can also reduce the number of steps required to update your data by compressing two or more queries into a single query.