Connect To PostgreSQL Database Server with Entity Framework (Code First Approach)

Summary: In this tutorial, you will learn how to connect to the PostgreSQL database server in the ASPNET WEB API using the EFCore Code First Approach.

According to the Postgres Website: PostgreSQL is an advanced, enterprise-class, and open-source relational database system. PostgreSQL supports both SQL (relational) and JSON (non-relational) querying.

PostgreSQL is a highly stable database backed by more than 20 years of development by the open-source community.

PostgreSQL is used as a primary database for many web applications as well as mobile and analytics applications.

To install PostgreSQL on your local server, please use this instruction.

Create an ASPNET WEB API

First, use the following command from the terminal to create an ASPNET WEB API with the name PostGresAPI

dotnet new webapi -o PostGresAPI

If you have created the WEB API project, navigate to the project and use the command “code .” to open the project in VS Code

We must install the below libraries using the NuGet package manager.

Npgsql.EntityFrameworkCore.PostgreSQL
Microsoft.EntityFrameworkCore
Microsoft.EntityFrameworkCore.Tools
Microsoft.EntityFrameworkCore.Design

Connect to the PostgreSQL database using your project

The following is the list of the connection parameters:

database: the name of the database that you want to connect.

user: the username used to authenticate.

password: password used to authenticate.

host: database server address e.g., localhost or an IP address.

port: the port number that defaults to 5432 if it is not provided.

We can modify the appsettings.json with the below values.

By doing the above, We have added a database connection string to the settings file

Next, Let’s create models we can use to pass our entities into the database. Create a Models folder then create a Student class in the Models folder:

We can next create a “Data” folder and then create the “ApplicationDbContext” class in the Data folder then add the below code.

Make Changes to the ConfigureServices method in the Startup File

We can make the below changes in the “ConfigureServices” method in the “Startup” class as well to link the connection string and the Database context to create the file in our PostgreSQL database.

Create a Database table

We can now create a database table. As we are using Entity Framework, we can use below database migration command from the terminal to create a migrations folder and then update the database.

dotnet ef migrations add InitialMigration

If successful, we should see the below message in the terminal and the migrations folder created.

“InitialMigration” is the name we have given to the migrations. When successfully done, we can now update the database with the following command from the terminal also

dotnet ef database update

If you check the database using the PostgreSQL database server, you can see that the below table has been created inside the database./

In this tutorial, you have learned how to connect to the PostgreSQL database server in an ASPNET WEB API using the Entity Framework Core Code first approach.