Do you want to be hired as a .NET Developer? Are you preparing for the interview? Are you doubtful about the type of Entity Framework questions that could be asked? Do you want to get the hang of Entity Framework Interview Questions? Then you have taken one step towards acing your dream job interview. This article contains a bunch of hand-picked questions having a high probability of getting asked.
The Entity Framework contains a set of technologies inside ADO.NET supporting the data-oriented software app development. Without caring for the underlying database tables, the Entity Framework developers can work with data in the form of data-specific objects. Examples of such data include customers as well as customer addresses.
Entity Framework enables developers to develop and maintain low-code data-oriented apps. Entity Framework is used with .NET Framework. Therefore Entity Framework apps can run on systems with .NET Framework (version starting with 3.5 SP1) installed.
This open-source ORM (object-relational mapping) framework was initially released by Microsoft in 2008 for .NET apps.
Before moving ahead, let us have a look at some insightful facts about Entity Framework:
A lot of versions have been released since its initial release because of its wide use in the industry. Currently, the two latest versions on the market are Entity Framework 6 and Entity Framework core.
A developer with knowledge of Entity Framework can earn an average salary of $105,000 per annum in the USA. The range of salary varies from $50,000 to $176,000 per annum.
As we have gained the basic knowledge of Entity Framework, let's go through Entity Framework Interview Questions (updated-2023) for each of the following separately:
Top Entity Framework Interview Questions
The three main components of the entity data model forming the basis of the Entity Framework are given below:
The following are the main components of Entity Framework architecture:
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It is also called the Conceptual Data Definition Language Layer or C-Space. It contains the entities/model classes as well as their relationships. This doesn't affect our database table design. It ensures that business objects and relationships are demarked in XML files.
It is also called the Mapping Schema Definition Language layer or C-S Space. This model includes the information about the mapping of the conceptual model to the storage model. We can say that this model maps the business objects and their relationships at the conceptual layer to tables and relationships at the logical layer.
It is also called the Store Space Definition Language Layer or S-Space. The storage area in the backend is represented by this model. That's why it's also referred to as the database design model composing stored procedures, keys, views, tables, and related relationships.
The Entity Framework introduced the migration tool for automatically updating the database schema whenever a model modifies without losing data. The two types of migration provided by Entity Framework are automated migration and code-based migration.
Classes can be automatically generated to interact within our application using the EDMX files. The conceptual models, storage models, and the mappings are represented by EDMX files. All the information about SQL objects and tables is contained in it. The essential information needed to render models graphically with ADO.NET is also contained. Its 3 divisions are MSL, CSDL, and SSDL.
The following methods are provided by Dataset objects to generate XML:
GetXml(): A string containing an XML document is provided by this method.c
ReadXml(): an XML document is read into a Dataset object by this method.
WriteXml(): The XML data is written to disk by this method.
T4 files are very important in the code generation of Entity Framework. The T4 code templates read the EDMX XML files. The C# behind the code is then generated by the T4. Just our entity and the context classes are contained in the generated C# behind code.
The navigation property represents a foreign key relationship in Entity Framework's database. The relationships among the entities in a database can be specified with the help of this property type. In the object-oriented code, the relationships are defined such that they remain coherent.
We can delay the evaluation of any expression till the time we want its realized value to appear. Therefore we can improve the performance significantly by avoiding unnecessary execution. Until the query object or query variable iterates over a loop, queries get deferred.
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Database concurrency arises when multiple users are accessing and modifying the same data simultaneously in the same database. And the concurrency controls are the systems by which the consistency of data is protected in such situations.
We can implement optimist locking to handle the database concurrency. We can implement the locking by right-clicking on the EDMX designer and setting the concurrency model to Fixed. If any concurrency issue exists, a positive concurrency exception error arises.
Entity Framework supports mainly 3 types of properties. And they are given below:
Its performance can be increased by:
Dbset- operations can be created, updated, read, and deleted on any entity set in a dbset class. We must include the dbset type properties mapping to the database tables and views in the context class (from dbcontext).
Dbcontext- It is an important class in Entity Framework API. This is used to connect a domain class or entity and the database. Its main responsibility is to communicate with the database.
POCO means 'Plain Old CLR Objects'. Still, it doesn't imply the oldness and plainness of these classes. A POCO class doesn't contain any reference to the .NET framework or Entity Framework. The POCO entities are the same as available domain objects in Entity Framework objects.
These classes are not dependent on any framework-specific base class. This is unlike the general .NET class. The entity object-derived LINQ queries are supported by POCO. And the POCO entities are supported by both EF core and EF 6.
The given loading types are offered by Entity Framework:
Lazy loading: The loading process of related objects is delayed till the time we need them. Only the objects we need are returned in the lazy loading. At the same time, the other related objects get returned only when we need them.
Eager loading: in this loading, all the related objects are also returned along with the object's query. All the related objects get loaded automatically along with the parent object. We can achieve eager loading in EF 6 by using the Include method.
Explicit loading: This occurs only when we desire lazy loading. The relevant load method should be explicitly called for processing explicit loading. We can achieve explicit loading in EF 6 by using the load method.
The following three are primary types of inheritance in Entity Framework:
ADO.NET supports the given two types of data access architecture:
We can follow the given three methods to execute plain SQL in Entity Framework:
|Do you want to know more about SQL, Take a Look at this SQL Tutorial|
The main responsibility of singularizing and pluralizing in Entity Framework is assigning the objects meaningful naming conventions. This feature can be accessed through the .edmx file. The coding conventions will be assigned to the singular and plural while this feature is used. The convention names have an extra 's' if there are two or more records within an object.
A micro ORM is not made to create database schemas, track changes, modify database schemas, etc. Instead, its primary function is to work with database tables. Because the Entity Framework Core and Entity Framework 6 have a complete set of functionalities and features, they are referred to as O/RMs.
Some of the O/RMs that we can use with applications based on .NET are listed below:
Optimistic Locking is the process of reading a record and noting a version number, timestamp, date, or hash. And then, we check that the record hasn't changed before writing the code back. While writing the record back, we filter the update on the version, ensuring that it's atomic. And then the version is updated in a single hit.
We can abort the transaction and then re-start it if the record is found dirty.
The hackers use this method of SQL injection to access sensitive information from the databases of organizations. This happens because of improper coding in the applications. This enables the hackers to inject SQL statements into our SQL code.
The main reason behind SQL injection is that the SQL statements are allowed by the user input fields to pass through and query the database directly.
We use namespace- System.Data.SqlClient for the inclusion of a .NET data provider for SQL server in our .NET code.
Some of the companies that use Entity Framework in their tech stack are given below:
PostgreSQL, MySQL, SQLite, Microsoft SQL Server, .NET, Oracle, Firebird, and IBM DB2 are some of the popular tools with which Entity Framework is integrated.
Some of the alternatives to Entity Framework are listed below:
MVC is a framework that focuses primarily on the way of delivering a webpage to the client from the server. While the Entity Framework enables you to access various abstract kinds of databases (MySQL, MSSQL, etc.) and query objects. It is an object-relational mapper, and it doesn't have SQL strings in the projects.
The advantages of Entity Framework are:
The following three types of Entity Framework approaches are there:
The Code First approach suits best when we have the domain classes already with us. On the other hand, the Database First approach is best when we have a database. And the Model First approach is used when we don't have a database or the model classes. The Model First approach provides us with the visual entity tool for designing.
It becomes tough to write and manage ADO.NET codes at times. And the Microsoft developed Entity Framework solves this problem of managing the tedious tasks. Entity Framework provides domain-specific objects as relational data. Hence, the code-based tasks get reduced significantly.
Entity Framework- It is slower than ADO.NET. No data layer codes are created by it. The data access layer codes, intermediate codes, and mapping codes are automatically created by it. This is the reason why they work and time of the developers get cut short.
ADO.NET- It is relatively faster. Several data layer codes are created by it. Codes are not created for the intermediate layers, data access layers, and mapping codes by ADO.NET.
The primary functions of Entity Framework are given below:
.NET developers can work with Entity Framework in the database with the help of .NET objects. Through this, we eliminate the conventional method of accessing data via code. And we can read as well as write from a database. Hence, this makes it highly valuable app development software. There are ample opportunities available in the market for .NET developers with Entity Framework knowledge. And we hope that we can provide significant help to all those individuals via this compilation of Entity Framework Interview Questions.
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