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https://github.com/jasonsturges/postgresql-dotnet-core

ASP.NET 7.0 Web Application using PostgreSQL with Entity Framework
https://github.com/jasonsturges/postgresql-dotnet-core

asp-net-core aspnet aspnetcore database dotnet dotnet-core entity-framework postgresql

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ASP.NET 7.0 Web Application using PostgreSQL with Entity Framework

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README 

        
# PostgreSQL ASP.NET 7



Convert an ASP.NET Core Web Application project to use PostgreSQL with Entity Framework.



This enables development of ASP.NET Core projects using [VS Code](https://code.visualstudio.com/) on macOS or linux targets.



This project uses [.NET 7.0](https://dotnet.microsoft.com/en-us/download/dotnet/7.0) target framework, ASP.NET Core Web Application MVC project scaffold from Visual Studio 2022 (version 17.4).



![vscode](https://user-images.githubusercontent.com/1213591/210010019-e4b11daf-03df-41b6-b44c-368f0cd3cfde.png)



Project setup has already been completed in this repository - assure [environment setup](#environment-setup); then, jump to [running the solution](#running-the-solution).



## Environment Setup



This project requires PostgreSQL - installation instructions are provided below.



If using Visual Studio Code, you will need to generate ASP.NET Core developer certificates by issuing the following commands from a terminal:



    dotnet dev-certs https --clean

    dotnet dev-certs https



For command line `database ef` commands, you will need to install Entity Framework Core tools .NET CLI:



    dotnet tool install --global dotnet-ef



## Project Setup



Below, instructions are referenced to use PostgreSQL in a ASP.NET Core project.



### Install NuGet packages



Install the `Npgsql.EntityFrameworkCore.PostgreSQL` NuGet package in the ASP.NET web application.



To do this, you can use the `dotnet` command line by executing:



    $ dotnet add package Npgsql.EntityFrameworkCore.PostgreSQL --version 3.1.2



Or, edit the project's .csproj file and add the following line in the `PackageReference` item group:



```xml



```



### Update appsettings.json



Configure connection string in project's appsettings.json, replacing the `username`, `password`, and `dbname` appropriately:



```json

"ConnectionStrings": {

    "DefaultConnection": "User ID=username;Password=password;Server=localhost;Port=5432;Database=dbname;Integrated Security=true;Pooling=true;"

},

```



### Modify Program.cs



Inside Program.cs replace the `UseSqlServer` options with `UseNpgsql`:



```cs

builder.Services.AddDbContext(options =>

    options.UseNpgsql(connectionString));

```

    



## Running the solution



Before the solution can be executed, be sure to run entity framework migrations.



### Migration Issues with DbContext



Initial migrations may fail, due to ASP.NET Core template come with a pre-generation migration for SQL Server.



When trying to run the migration, you might see errors such as:

> Npgsql.PostgresException (0x80004005): 42704: type "nvarchar" does not exist

>

> System.NullReferenceException: Object reference not set to an instance of an object.

>

> System.InvalidOperationException: No mapping to a relational type can be found for property 'Microsoft.AspNetCore.Identity.IdentityUser.TwoFactorEnabled' with the CLR type 'bool'.



Delete the entire Migrations folder, and regenerate new inital migrations.



Generate a new migration using Visual Studio Package Manager Console (from menu: Tools -> NuGet Package Manager -> Package Manager Console):



    PM> Add-Migration



Or, from the command line via DotNet CLI:



    $ dotnet ef migrations add Initial



If dotnet migration tools don't exist, remember to install the tools using the instruction above in the [environment setup](#environment-setup).



### Run Entity Framework Migrations



Execute the migration using either Visual Studio Package Manager Console (from menu: Tools -> NuGet Package Manager -> Package Manager Console):



    PM> Update-Database



Or, from the command line via DotNet CLI, execute the following command inside the project directory, **where the .csproj file is located**:



    $ dotnet ef database update



After running the migration, the database is created and web application is ready to be run.



## Setting up a PostgresSQL server on Mac



Here are instructions to setup a PostgreSQL server on Mac using Homebrew.



### Installing PostgreSQL on Mac



Use [brew](https://brew.sh/) to install PostgreSQL, then launch the service:



    $ brew install postgresql

    $ brew services start postgresql



### Create a user



Create a user using the `createuser` command from a terminal, where `username` is your desired new user name.  Using the `-P` argument, you will be prompted to setup a password.



    $ createuser username -P



### Create a database



Create your database using the `createdb` command from a terminal, where `dbname` is your desired new database name.



    $ createdb dbname

    

At this time, run the solution's Entity Framework migrations (see above for instructions).



### Verifying database



Launch PostgreSQL interactive terminal and connect to the database.



    $ psql dbname



From the PostgreSQL interface terminal, List tables using the `\dt` command:



    dbname=# \dt

                       List of relations

     Schema |         Name          | Type  |    Owner     

    --------+-----------------------+-------+--------------

     public | AspNetRoleClaims      | table | username

     public | AspNetRoles           | table | username

     public | AspNetUserClaims      | table | username

     public | AspNetUserLogins      | table | username

     public | AspNetUserRoles       | table | username

     public | AspNetUserTokens      | table | username

     public | AspNetUsers           | table | username

     public | __EFMigrationsHistory | table | username

    (8 rows)



### Database permissions issues



If permissions were not setup properly during the creation of the database, retroactively fix by granting privileges where `dbname` is your database name and `username` is the user you created:



    $ psql dbname

    dbname=# GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO username;