使用 Multipass（官方轻量虚拟 Ubuntu）

 

轻量方案：使用 Multipass（官方轻量虚拟 Ubuntu）

如果你只是想运行命令行版 Ubuntu（不需要桌面），可以用 Canonical 官方工具 Multipass。

安装：

brew install --cask multipass

创建 Ubuntu 虚拟机：

multipass launch --name ubuntu --mem 4G --disk 20G

 

进入虚拟机：

multipass shell ubuntu

删除虚拟机：

multipass delete ubuntu && multipass purge

👉 它运行的是 Ubuntu LTS，启动秒级，非常轻量。

docker host name/address

if don't wanna use the ip address

docker get IP address command:

docker inspect -f '{{range. NetworkSettings. Networks}}{{. IPAddress}}{{end}}' container_name_or_id

use host.docker.internal

 

.Net Core connect to postgresql

 1. appsettings.json

  "ConnectionStrings": {
    "DefaultConnection": ""
  }

2. Program.cs

builder.Services.AddDbContext<ApiDbCopntext>(options => options.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection")));

3. Models/ folder

add Table Class

namespace ReactAPIApp.Server.Models

{

    public class Driver

    {

        public int Id { get; set; }

        public string Name { get; set; } = null!;

        public int DriverNumber { get; set; }

    }

}

4. Add Context for example add Data folder

Data/ApiDbContext.cs

using Microsoft.EntityFrameworkCore;

using ReactAPIApp.Server.Models;

namespace ReactAPIApp.Server.Data
{
    public class ApiDbContext : DbContext
    {
        public ApiDbContext(DbContextOptions<ApiDbContext> options) : base(options){}
        public DbSet<Driver> Drivers { get; set; }
    }
}

5. run migrate command

if from package manager console
PM> Add-Migration initial

if from package manager console

js function 严格模式 use strict

 禁止function 内部的this指向winodows

class 中的function，都已默认开启了严格模式

.Net seed migration

dbcontext command lines:

1. Using the Package Manager Console in Visual Studio:

Add-Migration initial 

remove-database

update-database

2. Using the .NET Command Line Interface (.NET CLI):

dotnet ef migrations add Initial

dotnet ef database update

Multi column searching

 scopeSearch

collect(explode(' ', $terms))->filter()->each(function （$tiem）use ($query) {

    $term = '%' . $term . '%';

    $query->where(function($query) use ($term) {

        $query->where('first_name', 'like', $term)

            ->orWhere('last_name', 'like', $term)

            ->orWhereHas('company', function($query) use ($term) {

                $query->where('name', like', $term);

            });

    });

});

to SQL it is

SELECT * FROM 'users'

WHERE 'first_name' LIKE '%bill%'

    OR 'last_name' LIKE '%bill%'

    OR EXISTS (

        SELECT * FROM 'companies'

        WHERE 'users'.'company_id' = 'companies'.'id'

    )

Optimizing Circular Relationships

 model/Comment.php

public function isAuthor() {// n + 1 issue

     return $this-->feature->comments->first()->user_id === $this->user_id;

}

Improves

in controllor

$feature->load('comments.user', 'comments.feature.comments');

Improves more

$feature->load('comments.user');

$feature->comments->each->setRelation('feature', $feature);