What is the purpose of drop Create database always database initializer in Entity Framework?
DropCreateDatabaseAlways: As the name suggests, this initializer drops an existing database every time you run the application, irrespective of whether your model classes have changed or not.
Which of the following are database initialization strategies in EF Code First?
DropCreateDatabaseAlways: This strategy of code first approach creates the database every time you run the application. If the database already exists and there is no modification done in the model, it will drop the database and create a new one. In this approach, you will also lose the data.
How do I connect to database in Code first approach?
View -> Server Explorer
- View -> Server Explorer.
- Right click on Data Connections and select Add Connection…
- If you haven’t connected to a database from Server Explorer before you’ll need to select Microsoft SQL Server as the data source.
- Connect to either LocalDB or SQL Express, depending on which one you have installed.
What is DB initializer?
The Database initialization strategy determines how the database is generated & updated when the underlying model changes. The entity framework provides us four strategies to handle these situations.
What is DbSet entity?
A DbSet represents the collection of all entities in the context, or that can be queried from the database, of a given type. DbSet objects are created from a DbContext using the DbContext.
What is database initialization?
When you initialize a database, you delete all data (including the application data and database catalog) and all log entries from the volumes. The configuration of the database (database parameters, volume definitions, and so on) is retained, however.
What is a DbSet?
A DbSet represents the collection of all entities in the context, or that can be queried from the database, of a given type. DbSet objects are created from a DbContext using the DbContext. Set method.
What is the difference between code first and database first?
In the code first approach, the programmer has to write the classes with the required properties first, while in the database first approach, the programmer has to create first the database using GUI.
What is EF model?
An EF model stores the details about how application classes and properties map to database tables and columns. There are two main ways to create an EF model: Using Code First: The developer writes code to specify the model.
What is DbSet <>?
How do I initialize a DB file?
On the File tab, click New, and then click Blank Database. Type a file name in the File Name box. To change the location of the file from the default, click Browse for a location to put your database (next to the File Name box), browse to the new location, and then click OK. Click Create.
Why code First is better than database first?
The main difference between Code First approach and Database First approach is that the Code First enables you to write entity classes and its properties first without creating the database design first.
What is DbContext and ObjectContext?
Definition. DBContext is a wrapper of ObjectContext that exposes the most commonly used features of ObjectContext. In contrast, Object Context is a class of the core Entity framework API that allows performing queries and tracking the updates made to a database using strongly typed entity classes.
How does Entity Framework connect to database?
Typically an Entity Framework application uses a class derived from DbContext. This derived class will call one of the constructors on the base DbContext class to control: How the context will connect to a database — that is, how a connection string is found/used.
What is OnConfiguring method?
The OnConfiguring method is called every time that an an instance of the context is created. Most providers include convenience methods that extend the DbContextOptionsBuilder type, so that configuration can be simplified.
What is a SQL connection string?
The connection string is an expression that contains the parameters required for the applications to connect a database server. In terms of SQL Server, connection strings include the server instance, database name, authentication details, and some other settings to communicate with the database server.
How to create a database initializer in Entity Framework?
In our last tutorial Database initializer in Entity Framework, we discussed the built-in initializers. The Entity framework comes with three built-in Initializers. Those are CreateDatabaseIfNotExists, DropCreateDatabaseAlways and DropCreateDatabaseIfModelChanges. You can build your own custom initializer if any of those does not satisfy your needs.
What is setinitializer in Entity Framework?
The SetInitializer must be called before the Context access the database. Hence it must be called in the constructor of the Context class. The SetInitializer method takes any class that implements IDatabaseInitializer . The EF has three built- in implementation for the same.
How to create a custom initializer?
You can create the custom Initialiser either by implementing the interface IDatabaseInitializer or by inheriting from one of the built-in initializers. You can create Custom Initializer by implementing the IDatabaseInitializer Interface as shown below
How does the Entity Framework work?
The entity framework does this using the database object. This class exists in the system.Data.entity namespace . This class manages the database and the connection to the database. This class has methods which allow us to create, delete or check for the existence of the Database. This class is implemented in DBcontext.