The document discusses Entity Framework Code First concepts including entities, DbContext, DbSet, and navigation properties. It provides examples of how to map existing database tables to Code First classes using data annotations. It also demonstrates how to perform basic CRUD operations using Code First including adding, querying, updating and deleting records. The document shows how to generate a Code First model from an existing database as well as how to create an empty Code First model and map classes using data annotations and navigation properties.
Assemblies are the building blocks of .NET Framework ; they form the basic unit of deployment, reuse, version control, reuse, activation scoping and security permissions. An assembly is a collection of types and resources that are created to work together and form a functional and logical unit.
.NET assemblies are self-describing, i.e. information about an assembly is stored in the assembly itself. This information is called Metadata. .NET also allows you to put additional information in the metadata via Attributes. Attributes are used in many places within the .NET framework.
For more information on .net visit : http://crbtech.in/Dot-Net-Training/
Assemblies are the building blocks of .NET Framework ; they form the basic unit of deployment, reuse, version control, reuse, activation scoping and security permissions. An assembly is a collection of types and resources that are created to work together and form a functional and logical unit.
.NET assemblies are self-describing, i.e. information about an assembly is stored in the assembly itself. This information is called Metadata. .NET also allows you to put additional information in the metadata via Attributes. Attributes are used in many places within the .NET framework.
For more information on .net visit : http://crbtech.in/Dot-Net-Training/
The outline of the presentation (presented at NDC 2011, Oslo, Norway):
- Short summary of OData evolution and current state
- Quick presentation of tools used to build and test OData services and clients (Visual Studio, LinqPad, Fiddler)
- Definition of canonical REST service, conformance of DataService-based implementation
- Updateable OData services
- Sharing single conceptual data model between databases from different vendors
- OData services without Entity Framework (NHibernate, custom data provider)
- Practical tips (logging, WCF binding, deployment)
Accessing loosely structured data from F# and C#Tomas Petricek
Slides from my talk at GOTO 2011. The presentation discusses how to bridge the impedance mismatch between the structure used in programming languages (classes, records, unions, ...) and structure used in data sources (database schema, XML file or JSON document). The talk shows how to solve this problem at three scales - using dynamic typing, by defining structure explicitly and using F# type providers.
ADO.NET by ASP.NET Development Company in india
ADO.NET is a data access technology from the Microsoft .NET Framework that provides communication between relational and non-relational systems through a common set of components.
Video :
Courtesy:
http://www.ifourtechnolab.com
dotNet Miami - June 21, 2012: Richie Rump: Entity Framework: Code First and M...dotNet Miami
dotNet Miami - June 21, 2012: Presented by Richie Rump: Traditionally, Entity Framework has used a designer and XML files to define the conceptual and storage models. Now with Entity Framework Code First we can ditch the XML files and define the data model directly in code. This session will give an overview of all of the awesomeness that is Code First including Data Annotations, Fluent API, DbContext and the new Migrations feature. Be prepared for a fast moving and interactive session filled with great information on how to access your data.
This paper’s aim is to point out the RAD ( Rapid application development) elements present in the Microsoft’s MVC 3 and WCF 4.0 using Microsoft Visual Studio 2010. It will describe why creating a new web application using MVC 3 and WCF 4.0 is a easy and fast and also present simple ways to develop such applications.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
2. Role of Entities
Entities are a conceptual model of a physical database that maps to your
business domain.
This model is termed an entity data model (EDM).
The EDM is a client-side set of classes that are mapped to a physical
database by Entity Framework convention and configuration.
The entities did not map directly to the database schema in so far as
naming conventions go.
You are free to restructure your entity classes to fit your needs, and the
EF runtime will map your unique names to the correct database schema.
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3. The Role of the DbContext Class
The DbContext class represents a combination of the Unit of Work and
Repository patterns that can be used to query from a database and group
together changes that will be written back as a single unit of work.
DbContext provides a number of core services to child classes,
including
The ability to save all changes (which results in a database update),
Tweak the connection string, delete objects, call stored procedures,
Handle other fundamental details
Create a class that derives from DbContext for your specific domain.
In the constructor, pass the name of the connection string for this
context class to the base class
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4. The Role of DbSet<T>
To add tables into your context, you add a DbSet<T> for each table in
your object model.
To enable lazy loading, the properties in the context need to be virtual.
Ex: public virtual DbSet<Customer> Customers { get; set; }
Each DbSet<T> provides a number of core services to each collection,
such as creating, deleting, and finding records in the represented table.
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5. The Role Navigation Properties
As the name suggests, navigation properties allow you to capture JOIN
operations in the Entity Framework programming model
To account for these foreign key relationships, each class in your model
contains virtual properties that connect your classes together
Ex: public virtual ICollection<Order> Orders { get; set; }
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6. Lazy, Eager, and Explicit Loading
There are three ways that EF loads data into models. Lazy and Eager
fetching are based on settings on the context, and the third, Explicit, is
developer controlled.
Lazy Loading
The virtual modified allows EF to lazy load the data. This means that EF
loads the bare minimum for each object and then retrieves additional
details when properties are asked for in code.
Eager Loading
Sometimes you want to load all related records.
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7. Lazy, Eager, and Explicit Loading
Explicit Loading
Explicit loading loads a collection or class that is referenced by a
navigation property.
By default, it is set to Lazy Loading and we can re-enable it by:
context.Configuration.LazyLoadingEnabled = true;
To use Eager loading, set the LazyLoadingEnabled = false;
To use Explicit loading, use the Load method
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8. Code First from Existing Database
Generating the Model
1. Create the solution for new application
2. (R.C.)Project=> Add New Item =>Select ADO.NET Entity Data
Model
3. Then choose Add. This will launch the “ADO.NET Entity Data
Model” Wizard
4. The wizard has 4 template:
1. EF Designer from Database
2. Empty EF Designer Model
3. Empty Code First Model
4. Code First from Database
5. Choose “Code First From Database”
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9. Code First from Existing Database
new classes in your project:
one for each table that you selected in the wizard
one named ……Entities (the same name that you entered in the first
step of the wizard).
By default, the names of your entities will be based on the original
database object names; however, the names of entities in your
conceptual model can be anything you choose.
You can change the entity name, as well as property names of the entity,
by using special .NET attributes referred to as data annotations.
You will use data annotations to make some modifications to your
model.
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10. Code First from Existing Database
Data annotations:
Data annotations are series of attributes decorating the class and properties in
the class
They instruct EF how to build your tables and properties when generating the
database.
They also instruct EF how to map the data from the database to your model
classes.
At the class level, the Table attribute specifies what table the class maps to.
At the property level, there are two attributes in use.
The Key attribute, this specifies the primary key for the table.
The StringLength attribute, which specifies the string length when generating
the DDL for the field. This attribute is also used in validations,
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11. Code First from Existing Database
Changing the default mapping
The [Table("Inventory")] attribute specifies that the class maps to the
Inventory table. With this attribute in place, we can change the name of
the class to anything we want.
Change the class name (and the constructor) to Car.
In addition to the Table attribute, EF also uses the Column attribute.
By adding the [Column("PetName")] attribute to the PetName property,
we can change the name of the property to CarNickName.
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12. Code First from Existing Database
Insert a Record (example)
private static int AddNewRecord()
{
// Add record to the Inventory table of the AutoLot database.
using (var context = new AutoLotEntities())
{
// Hard-code data for a new record, for testing.
var car = new Car() { Make = "Yugo", Color = "Brown",
CarNickName="Brownie"};
context.Cars.Add(car);
context.SaveChanges();
}
return car.CarId;
}
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13. Code First from Existing Database
Selecting Record (example)
private static void PrintAllInventory()
{
using (var context = new AutoLotEntities())
{
foreach (Car c in context.Cars)
{
Console.WriteLine(“Name: “+ c.CarNickName);
}
}
}
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14. Code First from Existing Database
Query with LINQ (example)
private static void PrintAllInventory()
{
using (var context = new AutoLotEntities())
{
foreach (Car c in context.Cars.Where(c => c.Make == "BMW"))
{
WriteLine(c);
}
}
}
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15. Code First from Existing Database
Deleting Record (example)
private static void RemoveRecord(int carId)
{
// Find a car to delete by primary key.
using (var context = new AutoLotEntities())
{
Car carToDelete = context.Cars.Find(carId);
if (carToDelete != null)
{
context.Cars.Remove(carToDelete);
context.SaveChanges();
}
}
}
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16. Code First from Existing Database
Updating Record (example)
private static void UpdateRecord(int carId)
{
using (var context = new AutoLotEntities())
{
Car carToUpdate = context.Cars.Find(carId);
if (carToUpdate != null)
{
carToUpdate.Color = "Blue";
context.SaveChanges();
}
}
}
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17. Empty Code First Model
Create the solution for new application
(R.C.)Project=> Manage NuGet Packages
From “Browse” tab, select “Entity Framework” then “Install”
Add the Model classes (class that will be mapped to a table)
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18. Empty Code First Model
Add the Model classes
Add files named: Customer.cs, Inventory.cs, Order.cs
In the Inventory.cs, change the class to “public partial”
Add the following namespaces (for using Data Annotation):
• System.ComponentModel.DataAnnotations
• System.ComponentModel.DataAnnotations.Schema
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19. Empty Code First Model
Inventory.cs
public partial class Inventory
{
public int CarId { get; set; }
public string Make { get; set; }
public string Color { get; set; }
public string PetName { get; set; }
}
Then add the Data Annotation
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20. Empty Code First Model
Inventory.cs
[Table("Inventory")]
public partial class Inventory
{
[Key]
public int CarId { get; set; }
[StringLength(50)]
public string Make { get; set; }
[StringLength(50)]
public string Color { get; set; }
[StringLength(50)]
public string PetName { get; set; }
}
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21. Empty Code First Model
Add the navigation properties
[Table("Inventory")]
public partial class Inventory
{
[Key]
public int CarId { get; set; }
[StringLength(50)]
public string Make { get; set; }
[StringLength(50)]
public string Color { get; set; }
[StringLength(50)]
public string PetName { get; set; }
public virtual ICollection<Order> Orders { get; set; } = new HashSet<Order>();
}
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22. Empty Code First Model
Customer.cs
public partial class Customer
{
[Key]
public int CustId { get; set; }
[StringLength(50)]
public string FirstName { get; set; }
[StringLength(50)]
public string LastName { get; set; }
[NotMapped]
public string FullName => FirstName + " " + LastName;
public virtual ICollection<Order> Orders { get; set; } = new HashSet<Order>();
}
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23. Empty Code First Model
Order.cs
public partial class Order
{
[Key, Required, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int OrderId { get; set; }
[Required]
public int CustId { get; set; }
[Required]
public int CarId { get; set; }
[ForeignKey("CustId")]
public virtual Customer Customer { get; set; }
[ForeignKey("CarId")]
public virtual Inventory Car { get; set; }
}
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24. Empty Code First Model
Adding the DbContext
(R.C.)The Project=> Add=> New Item=> ADO.NET Entity Data Model
Select “Empty Code First Model”
Update the *.config file and EF connection string
<add name="AutoLotConnection" connectionString="data
source=.SQLEXPRESS2014;initial catalog=AutoLot2;integrated
security=True;MultipleActiveResultSets=True;App=EntityFramework"
providerName="System.Data.SqlClient" />
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25. Empty Code First Model
The DbContext file
The constructor for your derived DbContext class passes the name of the
connection string to the base DbContext class.
Open the .cs:
add the connection string to the constructor
add a DbSet for each of the model classes.
• public virtual DbSet<Customer> Customers { get; set; }
• public virtual DbSet<Inventory> Inventory { get; set; }
• public virtual DbSet<Order> Orders { get; set; }
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