This
is a step-by-step walkthrough which will create a new database using
C# code. We will create one console Application which will create an
empty database and will also add new tables too.
2. Create the Model
Now we will create two simple model(Employee, Manager) using classes. As a part of demo I'll define both in Program.cs but in a real word application we should define in two separate file/classes.
Add the following two classes in Program.cs.
3.
Create a Context
Before creating a context, first we will install the EntityFramework Nuget package.
DbContext has created a database for you. You need to check it into your SQL Express instance or If you have installed it then it will be in your LocalDb. (Both are installed by default with Visual Studio 2013). Click here if you don't know how to connect to database.
The database is named after the fully qualified name of the derived context, In our case that is CreateNewDatabase.ManagingContext
Pre-Requisities
We
need to have Visual Studio 2013 installed to complete this
walkthrough.(You can use older version too like 2010 or 2012 to
complete this tutorial.)
Steps
:
1. Create new Application
1. Create new Application
- Open Visual Studio, Click File -> New -> Project
- Click Console Application under templates -> Visual C# -> Windows
- Enter Name as CreateNewDatabase and Select OK
2. Create the Model
Now we will create two simple model(Employee, Manager) using classes. As a part of demo I'll define both in Program.cs but in a real word application we should define in two separate file/classes.
Add the following two classes in Program.cs.
public
class
Manager
{
public
int
ManagerId { get;
set;
}
public
int
ManagerName { get;
set;
}
public
virtual
List<Employee>
Employees { get;
set;
}
}
public
class
Employee
{
public
int
EmployeeId { get;
set;
}
public
String
EmployeeName { get;set;
}
public
String
EmployeeDesignation { get;
set;
}
public
int
ManagerId {get;set;}
public
virtual
Manager
Manager { get;
set;
}
}
If
you have notice I have made the two navigation properties
(Manager.Employee and Employee.Manager) virtual. This enables the
Lazy Loading feature of Entity Framework. Lazy Loading means that the
contents of these properties will be automatically loaded from the
database when you try to access them.Before creating a context, first we will install the EntityFramework Nuget package.
- Click Project -> Manage NuGet Packacges
- Select the online tab and then select the EntityFramework Package and Install.
Now
we need to create a session so that we can query and save data into
the database, we need to define a derived context
(System.Data.Entity.DbContext) and exposes a typed DbSet<Entity>
for each class in our model.
Add
following derived context in the the Program.cs file.
public
class
ManagingContext
: DbContext
{
public
DbSet<Manager>
Blogs { get;
set;
}
public
DbSet<Employee>
Posts { get;
set;
}
}
Program.cs
:
using
System;
using
System.Collections.Generic;
using
System.Linq;
using
System.Text;
using
System.Threading.Tasks;
using
System.Data.Entity;
namespace CreateNewDatabase
{
class Program
{
static void Main(string[] args)
{
}
}
public class Manager
{
public int ManagerId { get; set; }
public String ManagerName { get; set; }
public String ManagerAddress { get; set; }
public virtual List<Employee> Employees { get; set; }
}
public class Employee
{
public int EmployeeId { get; set; }
public String EmployeeName { get;set; }
public String EmployeeDesignation { get; set; }
public int ManagerId {get;set;}
public virtual Manager Manager { get; set; }
}
public class ManagingContext : DbContext
{
public DbSet<Manager> Managers { get; set; }
public DbSet<Employee> Employees { get; set; }
}
}
{
class Program
{
static void Main(string[] args)
{
}
}
public class Manager
{
public int ManagerId { get; set; }
public String ManagerName { get; set; }
public String ManagerAddress { get; set; }
public virtual List<Employee> Employees { get; set; }
}
public class Employee
{
public int EmployeeId { get; set; }
public String EmployeeName { get;set; }
public String EmployeeDesignation { get; set; }
public int ManagerId {get;set;}
public virtual Manager Manager { get; set; }
}
public class ManagingContext : DbContext
{
public DbSet<Manager> Managers { get; set; }
public DbSet<Employee> Employees { get; set; }
}
}
4.
Reading and Writing Data
Now
its the time to implement the Main method in Program.cs. It will
create a new instance of our context and then uses it to insert a new
Manager. I have used LINQ query to retrieve all Manager entry from
the database.
class
Program
{
static
void
Main(string[]
args)
{
using
(var
db = new
ManagingContext())
{
//
Create and save a new Manager entry
Console.Write("Enter
a name for a new Manager: ");
var
name = Console.ReadLine();
var
manager = new
Manager
{ ManagerName = name };
db.Managers.Add(manager);
db.SaveChanges();
//
Display all Managers from the database
var
query = from
b in
db.Managers
orderby
b.ManagerName
select
b;
Console.WriteLine("All
Managers in the database:");
foreach
(var
item in
query)
{
Console.WriteLine(item.ManagerName);
}
Console.WriteLine("Press
any key to exit...");
Console.ReadKey();
}
}
}
Now
Run the Application :
DbContext has created a database for you. You need to check it into your SQL Express instance or If you have installed it then it will be in your LocalDb. (Both are installed by default with Visual Studio 2013). Click here if you don't know how to connect to database.
The database is named after the fully qualified name of the derived context, In our case that is CreateNewDatabase.ManagingContext
