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RSS订阅转载 SQL Server - 列出所有外键
select schema_name(fk_tab.schema_id) + '.' + fk_tab.name as foreign_table, '>-' as rel, schema_name(pk_tab.schema_id) + '.' + pk_tab.name as primary_table, substring(column_names, 1, len(column_names)-1) as [fk_columns], fk.name as fk_c.
2020-07-03 09:09:54
876
转载 Javascript - JSON.stringify - Circular Structure
let cache = []; let result = JSON.stringify(pool.pool, (key, value) => { if (typeof value === 'object' && value !== null) { // Duplicate reference found, discard key if (cache.includes(value)) return; ...
2020-06-09 11:58:48
389
原创 Javascript - NodeJS - Convert buffer to stream
The most effective way:const stream = require('stream');// The bufferlet buffer = Buffer.from("Hello world!", "utf-8");// The stream from bufferlet bufferStream = new stream.PassThrough();buff...
2020-03-31 11:32:11
544
转载 Javascript - Consuming Readable Streams with Async Iterators
// https://nodejs.org/api/stream.html#stream_class_stream_passthrough// search: Consuming Readable Streams with Async Iterators(async function () { for await (const chunk of file.stream()) { ...
2020-03-30 10:44:49
176
原创 Javascript - async await
// 1. async functions always return a Promise// 2. await will return resolved data of a promise, it can be a 'data or an 'error'.// An async function: getDataPromise()const getDataPromise = (num)...
2020-03-23 08:30:40
164
转载 Javascript - Callback, Promise and Promise Chaining
// 1. Use callback in an async function, call the callback when necessary during the async call.const getValueFunc1 = (key, callback) => { setTimeout(() => { callback(null, "Data f...
2020-03-23 07:39:46
164
原创 Javascript - var function scope.
varvariables are ‘function scope.’ What does this mean? It means they are only availableinsidethe function they’re created in, or if not created inside a function, they are ‘globally scoped.’var...
2020-03-08 20:50:37
189
原创 Cassandra learning notes
Installation:https://www.youtube.com/watch?v=EEXtVn3zAqc&list=PLalrWAGybpB-L1PGA-NfFu2uiWHEsdscD&index=3Commands: 1. Start cassandra: Cassandra.bat -f 2. Open cql command li...
2020-03-03 14:00:11
185
原创 Some commands
------------New projects------------1. dotnet new classlib -n Infrastructure2. dotnet sln add Infrastructure3. dotnet add reference ../application/------------User secrets-------------1. Initia...
2020-02-12 12:04:50
137
原创 c# - 汉字数字，阿拉伯数字，相互转换
using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace DesignPatterns.ChineseNumConvertor{ public class Node { public string Unit { get; set...
2020-02-02 12:57:32
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原创 c# - entityframework core - switch databases
更换数据库之后，如果旧的Migrations导致数据库错误，可按照以下步骤重新生成Migrations：1. 删除所有existing migrations（包含：DataContextModelSnapshot）, 直接文件删除就可以。2. 安装要更换数据库DataProvider的nuget package，例如：SqlServer的nuget package为：Microsoft.En...
2020-01-25 13:14:08
1546
原创 c# - Entityframework Core, code first, add a new table and it's relationships.
1. Define a new class, include existing class: AppUser. public class UserFollowing { public string ObserverId { get; set; } public virtual AppUser Observer { get; set; } ...
2020-01-20 11:04:28
283
原创 c# - Asp.net Core Identity - 操作步骤
1. Define a new class, derived from IdentityUserpublic class AppUser : IdentityUser { public string DisplayName { get; set; } }2. In your DataContext, change'public class DataCo...
2020-01-11 12:29:39
1380
原创 c# - Task again
using System;using System.Threading.Tasks;namespace TestTask{ class Program { static void Main(string[] args) { T1(); T2().Wait(); T3...
2020-01-11 12:01:28
269
原创 c# - CancellationToken Demo
using System;using System.Threading;using System.Threading.Tasks;namespace TaskCancellationTest{ class Program { static void Main(string[] args) { Cancellatio...
2020-01-05 12:30:21
439
转载 VSCode - Task.json同时Build多个Projects.
https://stackoverflow.com/questions/52238171/how-to-run-multiple-tasks-in-vs-code-on-build
2019-12-27 21:04:39
1453
原创 EntityFramwork Core - Reverse Engineering
基于Db Model->Update数据库Schema：应用migration1：1. 修改你的Db Model2. 执行：Add-Migration migration1 -Context "MyDbContext"3. 执行：Update-Database -Context "MyDbContext"撤销：migration11. 执行：Update-Database ‘...
2019-12-20 13:00:11
199
原创 Using .net core with Sqlite+password
1. 在.net framework下设置Sqlite密码，访问数据，重设密码，删除密码。using System;using System.Data.SQLite;namespace ConsoleApp1{ class Program { private const string password = "abc.123"; stat...
2019-12-20 12:37:51
1600
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原创 Asp.net Core - Custom middleware
public class PrintSomethingMiddleware { private readonly RequestDelegate _next; public PrintSomethingMiddleware(RequestDelegate next) { _next = next; }...
2019-12-15 14:41:46
151
转载 Asp.net Core - File Logging
https://nblumhardt.com/2016/10/aspnet-core-file-logger/
2019-12-15 11:18:38
231
转载 c# - Expression Tree and Why?
https://www.tutorialsteacher.com/linq/expression-treeusing System;using System.Linq.Expressions;namespace LambdaExpression{ public class Student { public string Name { get; set;...
2019-12-12 11:51:37
125
原创 C# - List of List 排列组合
public static List<List<T>> AllCombinationsOf<T>(List<List<T>> sets) { var combinations = new List<List<T>>(); forea...
2019-12-12 10:20:08
333
转载 c# - Getting Started with Entity Framework Core: Database-First Development
https://www.codeproject.com/Articles/1209903/Getting-Started-with-Entity-Framework-Core-Databas
2019-12-12 10:18:34
141
原创 c# - async, await
using System;using System.Threading;using System.Threading.Tasks;namespace AsyncAwaitDemo{ public delegate Task MyDelegate(); class Program { static async void Call() ...
2019-12-06 12:35:16
87
原创 c# - 控制台程序 合并Dll 不使用任何第三方插件
准备工作：1. 新建一个控制台程序Project：CombinedDlls.2. 再新建一个Class Library Project: ThirdPartyTool，新建一个类Util.cs, 在其中实现一个static的SayHelloTo(string name)方法。3.CombinedDlls引用ThirdPartyTool，并在代码中调用SayHelloTo方法。Sa...
2019-12-01 13:41:39
507
原创 c# - events 观察者模式
using System;namespace EventsDemo{ class Program { static void Main(string[] args) { Cat cat = new Cat() { Name = "Tom" }; Mouse mouse1 = new Mouse...
2019-11-25 13:42:52
100
原创 c# - struct和class的区别
1. struct不可以有无参数的构造函数2. 如果struct存在构造函数，所有属性必须在构造函数中初始化3. 不可以在struct中直接初始化属性4. struct可以不使用new初始化5. 若struct没有使用new初始化, 所有属性赋值之后, 对象才可以使用6. struct不可被继承7. struct可以实现接口（与class一致）8. struct是值类型，class是...
2019-11-25 11:57:41
128
原创 c# - Object Pooling（对象池）
Object pooling的主要目的是提升程序性能。代码会先从Pool中取得已经建好的对象实例，如果Pool中没有对象实例才需要重新创建，以下代码是一个示例：namespace ObjectPool{ using System; using System.Collections; class Program { static void M...
2019-11-20 15:52:16
1709
转载 标点符号 英文
转载自：http://www.ruanyifeng.com/blog/2007/07/english_punctuation.html． period or full stop 句号， comma 逗号： colon 冒号； semicolon 分号！ exclamation mark 惊叹号？ question mark 问号- hyphen 连字符* asterisk 星号...
2019-11-19 16:51:51
135
转载 System.web vs System.webserver 的区别是什么？
https://forums.asp.net/t/1642328.aspx?What+s+the+purposes+of+and+differences+between+system+web+and+system+webServer+
2019-11-04 18:08:36
1015
转载 python - pip install 不同 python 版本
py -2 -m pip install SomePackage # default Python 2py -2.7 -m pip install SomePackage # specifically Python 2.7py -3 -m pip install SomePackage # default Python 3py -3.4 -m pip install Some...
2019-10-08 17:34:03
508
转载 Javascript - A Set class
// 9.6.1 A Set Class function Set() { this.values = {}; this.n = 0; this.add.apply(this, arguments); } Set.prototype.add = function() { for(var i = 0 ...
2019-10-05 11:30:44
134
原创 Javascript - 继承 Inheritance
继承关系/* Java: 1. Instance fields 2. Instance methods 3. Class fields 4. Class methods Javascript: 1. Constructor object => class methods and class fields 2. ...
2019-10-04 22:40:55
126
转载 Javascript - 方法注入 Method Injection 'monkey-patching'
读Javascript: The Definitive Guide这本书的时候发现一个有意思的代码，可以在调用方法的之前和之后注入一些回调或者代码，分享给大家：// Define a method.function addBy10(val) { return val + 10;}var obj = { 'myMethod': addBy10 };obj.myMethod(5)...
2019-10-02 21:29:26
215
原创 c# - Owin Katana
https://docs.microsoft.com/en-us/aspnet/aspnet/overview/owin-and-katana/an-overview-of-project-katana
2019-09-23 22:39:36
239
原创 c# - 文字 中心 旋转
public static void DrawRotatedTextAt(Graphics gr, float angle, string txt, float x, float y, Font the_font, Brush the_brush) { // Text rectangle var fontRect =...
2019-09-22 17:03:07
937
转载 Javascript - Object Utility
/** Copy the enumerable properties of p to o, and return o.* If o and p have a property by the same name, o's property is overwritten.* This function does not handle getters and setters or copy at...
2019-09-03 23:51:59
289
转载 Python - why we use if __name__ == "__main__" in python code.
https://stackoverflow.com/questions/419163/what-does-if-name-main-do
2019-09-02 18:00:02
135
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