使用EF从数据库获取数据

Question

I've recently started working with EF6 So my knowledge on it isn't very great. I am currently working on test web project which I have created using VS Express 2013. EF has created the required tables. Now I've added my own table which has basic information such as:

FirstName

Surname

DOB

What I'm trying to gather is would I write a SQL query in my function to get the data from the database so something like

using (SqlConnection connection = new SqlConnection(myConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("select * from my table", connection))
        {
            connection.Open();
            using (SqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    //Read Data
                }
            }
        }

Or is there a separate way to write it in EF? Because I couldn't find how and where the SQL syntax queries are used in EF or maybe I'm just missing something? Thanks in advance for your help & support

Answer 1

Entity Framework (EF) is an object-relational mapper that enables .NET developers to work with relational data using domain-specific objects. It eliminates the need for most of the data-access code that developers usually need to write.

You need to review more there http://msdn.microsoft.com/en-gb/data/ef.aspx and at least read some intros to EF or some video tutorials.

var context = new EntitiesContext();//DbContext Object
 var list = ent.Customers; // will return all customers.

Answer 2

The code you have posted is using ADO.Net. You can perform raw sql in entity framework like this

 Entities ent = new Entities();//DbContext Object
 var list = ent.tablename.SqlQuery("select * from my table");

And using Entity framework to get data from db

Entities ent = new Entities();//DbContext Object
var data = ent.tableName;

Answer 3

The point of EF is that you don't have to write SQL queries. You have an object model you use to access the database:

using (var context = new YourEntities())
{
    var records = context.Table; // .Where(t => t.Name == "foo")
    foreach (var record in records)
    {
        // ...
    }
}

Answer 4

Please check out the Quickstart example from MSDN

http://msdn.microsoft.com/en-us/library/vstudio/bb399182%28v=vs.100%29.aspx