We would cover the following in this tutorial<\/b><\/p>\n <\/p>\n In Tutorial 5, we\u00a0 installed SQL Server and then used SQL Server Management Studio to create the Employees sample database we would use to store the employees data. We also created the relationships between the tables using database diagrams.<\/p>\n In Tutorial 6, we went back to Visual Studio and created the Entity Data Model using Entity Framework. This makes is possible to automatically sync our .Net code with out database without having to write any stored procedure or any SQL queries.<\/p>\n <\/p>\n You need to understand what changes took place when you created the Entity Data Model<\/p>\n In the Solution Explorer, find EmployeeDataModel.edmx <\/p>\n <\/p>\n Notice that the Models have been created automatically for<\/p>\n In Tutorial 3, we created the model file (Employee.cs) manually inside the Models folder, but in this case, the model files have been generated automatically from an existing database. This is known as Entity Framework – Database First.<\/p>\n <\/p>\n Expand the Controller folder. Notice that we have already one controller file, the EmployeesController <\/p>\n <\/p>\n Give it a name CountryController <\/p>\n <\/p>\n We would write a POST method that would insert a record into the database using the data from the body of the HTTP POST request. <\/p>\n <\/p>\n Listing 7.1<\/b>: POST Method for Country<\/p>\n <\/p>\n The code is quite simple. The EmployeeDBEntities is known as a database context and provides functionality to handle database operations like Add(), Remove(), Delete() and SaveChanges().<\/p>\n In this case, we got a Country object from the body of the request. Then extracted the fields\u00a0 and used them to create a new Country which is given to the Add() method as parameter. The Add method runs some kind of insert query against the database. Before we test this code, write a code to retreive a list of countries. This is given in Listing 7.2. <\/p>\n <\/p>\n Listing 7.2:<\/b> Code to Get List of Countries<\/p>\n <\/p>\n So now you have the POST method to Add a new Country as well as a GET method to retrieve the list of countries <\/p>\n\n
1. Review of Tutorial 5 and Tutorial 6<\/h3>\n
2. Examine the Changes to the Application Structure<\/h3>\n
\n(The edmx file is a container for both the designer\/class diagrams and the models, the .cs files that hold the classes)
\nExpand this file to display the content. The folder structure is as shown in Figure 1<\/p>\n![](\"https:\/\/2.bp.blogspot.com\/-Tlv3lnC84SE\/Wrw-2ZRXW8I\/AAAAAAAABqs\/mA0PAKUCCG4hhJ-xvx3Lmbur8sd5mOmEACLcBGAs\/s400\/EntityDataModel%2BTutorial%2B5%2BFigure%2B1.jpg\")
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3. Create the Controllers<\/h3>\n
\nYou now need to create the controllers for Country
\nRight-click on the Controllers folder and Choose Add > Controller
\nChoose Web 2 API Controller Empty and shown in Figure 2<\/p>\n![](\"https:\/\/4.bp.blogspot.com\/-WEahpbC9jfg\/WrxDLqD1FCI\/AAAAAAAABq8\/gYBm0POX9aYbFquAbgdE65AoZ2CZi6kxACLcBGAs\/s400\/API%2BController%2B-%2BEmpty.jpg\"){kind=spacer}
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\nClick Add. So the CountryController is added<\/p>\n4. Write a POST Method for Country<\/h3>\n
\nOpen the Country Controller file you created
\nCopy and paste the code in Listing 7.1 inside the class<\/p>\n\/\/METHOD TO ADD A NEW COUNTRY<\/span>\r\n[HttpPost]<\/span>\r\npublic<\/span> IHttpActionResult AddCountry<\/span>([FromBody]Country country)\r\n{\r\n using<\/span> (var<\/span> db = new<\/span> EmployeeDBEntities())\r\n {\r\n db.Countries.Add(new<\/span> Country() \r\n {\r\n Id = country.Id,\r\n Name = country.Name,\r\n Capital = country.Capital,\r\n Code = country.Code,\r\n Nationality = country.Nationality\r\n }\r\n );\r\n db.SaveChanges();\r\n }\r\n return<\/span> Created<\/span>(Request.RequestUri, Request.Content);\r\n}<\/pre>\n
\nThe SaveChanges() commits the query.<\/p>\n
\nCopy and paste this code into the CountryController.<\/p>\n[HttpGet]<\/span>\r\npublic<\/span> IEnumerable<Country> getCountries()\r\n{\r\n var<\/span> db = new<\/span> EmployeeDBEntities();\r\n return<\/span> db.Countries;\r\n}<\/pre>\n
\nBuild the project and make sure it builds successfully.<\/p>\n5. Insert some Countries Using the POST Method<\/h3>\n