今日已更新 212 条资讯 | 累计 24871 条内容
关于我们

标签:#an

找到 1848 篇相关文章

AI 资讯

Power BI Data Modeling Unleashed: Master Schemas, Relationships, and Joins for High-Performance Reporting

Whether you're brand new to Power BI or just getting started with data analytics, this guide walks you through everything you need to know about data modeling — from how tables connect, to the schemas that make your reports fast and reliable. What Is Data Modeling in Power BI? Imagine you have three spreadsheets: one with your customers , one with your products , and one with your sales transactions . Individually, each table tells you something. But together, they can tell you which customer bought which product, when, and for how much . That's exactly what data modeling is: the process of organizing your data tables and defining how they relate to each other so Power BI can combine them into meaningful reports and dashboards. A data model in Power BI has three core building blocks: Tables — your data sources (Excel files, databases, CSVs, cloud services, etc.) Relationships — the links between tables that tell Power BI how data connects Measures & Calculations — formulas (in DAX) that compute totals, averages, and other insights A well-designed data model is the difference between a report that loads in seconds and one that takes forever. It's also what keeps your numbers accurate and your dashboards easy to use. Why Does Data Modeling Matter? Here's a simple analogy: a city without roads is just a collection of buildings. Data modeling is the road system that lets you travel between your tables. Without a good data model: Your visuals may show incorrect or duplicated numbers Filters in one chart won't affect another Reports will be slow and hard to maintain With a good data model: Clicking on a customer in one visual automatically filters every other visual Calculations are accurate and consistent You can easily add new data sources without rebuilding everything Types of Tables: Facts vs. Dimensions Before diving into schemas and relationships, you need to understand the two types of tables that make up most Power BI models. Fact Tables A Fact table stores the ev

2026-06-22 原文 →
AI 资讯

The Imitation Game: Most people think they can spot an AI. Are you sure?

This is a submission for the June Solstice Game Jam What I Built The Imitation Game The Imitation Game is a real-time multiplayer social deduction game inspired by Alan Turing's famous Imitation Game the thought experiment that eventually became known as the Turing Test. Most people believe they can easily tell the difference between an AI and a human. They assume AI is too perfect, too logical, too fast, or too obvious. The Imitation Game challenges that assumption. Players enter a live chat room convinced they'll spot the machine within minutes. Then conversations begin, suspicions form, accusations fly, and certainty starts to disappear. Was that awkward response written by a human, or an AI trying to sound human? Was that emotional story genuine, or generated? Was the player who stayed silent suspicious, or simply distracted? By the end of a match, players often discover that identifying an AI is far harder than they expected. The real question isn't whether the machine can fool people. It's whether people are as good at detecting machines as they think they are. Instead of a single human interrogating a machine, players are placed into a live chat room with other participants and asked a simple question: Can you identify which player is actually an AI? Hidden among the players is a Quanbit , a rogue artificial intelligence from the year 3026 . Its mission is simple: blend in, appear human, avoid suspicion, and survive. The challenge for human players is equally simple, but far more difficult in practice. They must carefully analyze conversations, voting patterns, response timing, and social behavior to determine who among them is secretly the machine. The game currently features two distinct modes, each designed around a different style of deception. Eyefold Eyefold is the purest form of the game's Turing Test experience. Players enter a room where one participant is secretly a Quanbit. Conversations unfold naturally, and everyone is free to discuss any topic.

2026-06-22 原文 →
AI 资讯

Angular Material Theming System Course — Now 100% Free

If you've worked with Angular Material, you know theming can be one of the trickiest parts of the library — especially after the move to Material 3. Token-based theming, custom palettes, dark mode, component-level overrides... there's a lot going on under the hood. I built a full course to break it all down, and I'm excited to announce it's now completely free . What's in the course Angular Material Theming System is a deep, practical walkthrough of Angular Material's theming API for Material 3. By the end, you'll be able to: Build and customize themes from scratch Apply themes at the application level Override and extend themes for individual components Work confidently with Angular Material's theming tokens and APIs It's 46 lessons and roughly 4.5 hours of content, all hands-on and example-driven. Where to find it 🎥 Watch on YouTube: https://www.youtube.com/playlist?list=PLOjtJUnDeEIyaeUs_jrxylnD2IxSb3Ku7 📝 Read the article version: https://angular-ui.com/courses/angular-material-theming/ 💻 Full source code on GitHub: https://github.com/Angular-UI-com/angular-material-theming If you're building with Angular Material and theming has ever felt like a black box, give it a watch. I'd love to hear your feedback in the comments. If this helped you, consider checking out Angular Material Blocks — a library of pre-built Angular Material + Tailwind components, available via a simple CLI.

2026-06-21 原文 →
AI 资讯

Building Real-Time Dashboards in Angular with WebSockets — A Complete Guide

Most dashboards are built the same way: the user lands on the page, data loads, and then... it sits there. Stale. Until the user hits refresh or you set up an awkward polling interval that hammers your server every few seconds. There's a better way. WebSockets give you a persistent, two-way connection between your Angular app and your server — meaning your dashboard updates the moment new data exists, with zero wasted requests. In this article we'll build a complete real-time dashboard in Angular from scratch — WebSocket service, Signal-based components, auto-reconnection, and production-ready patterns. How WebSockets Differ From Regular HTTP Before writing any code, it's worth understanding what makes WebSockets special. Regular HTTP: Client → "Give me data" → Server Client ← "Here's your data" ← Server [Connection closes] WebSocket: Client ←→ Server [Connection stays open] Server → "New data!" → Client (anytime) Server → "More data!" → Client (anytime) Client → "Send this" → Server (anytime For a real-time dashboard showing live metrics, user activity, or financial data — the WebSocket model is a natural fit. The server pushes updates the moment they happen. No polling, no refresh button, no stale data. Project Setup For this article we'll build a dashboard that shows three live metrics: active users, requests per second, and server CPU usage. Start with a fresh Angular 22 project: ng new realtime-dashboard --standalone cd realtime-dashboard ng serve RxJS ships with Angular so no extra dependencies are needed — webSocket from rxjs/webSocket handles everything. Step 1 — Define Your Data Model Start with a clear TypeScript interface for the data your server will push: // core/models/dashboard.model.ts export interface DashboardMetrics { activeUsers : number ; requestsPerSecond : number ; cpuUsage : number ; timestamp : Date ; } export interface MetricAlert { type : ' warning ' | ' critical ' ; metric : string ; value : number ; message : string ; } export type Dashb

2026-06-21 原文 →
AI 资讯

PARA Method for Engineers: Organize Knowledge by Action

Organizing notes by topic sounds logical until you have notes on PostgreSQL in five different folders and cannot find the one that matters for today's problem. The issue is not discipline. The issue is that topic-based organization asks the wrong question. "What is this about?" is useful for libraries. For engineers, the better question is "What am I doing with this?" That is the premise of PARA. PARA is a simple four-bucket system created by Tiago Forte as the organizational backbone of his Building a Second Brain framework. The idea is that all information can be sorted into four categories: Projects, Areas, Resources, and Archives. Each category represents a different level of actionability, and that distinction drives where every note lives. This guide applies PARA to engineering work specifically — codebases, documentation, learning material, and the tension between active project work and long-term reference. The Problem With Topic-Based Organization Most engineers organize knowledge the way they organize code: by domain. databases/ postgresql/ redis/ api/ rest/ graphql/ devops/ kubernetes/ terraform/ That structure makes sense when you are browsing. It breaks down when you need something for a specific task. You remember a useful note about database migration safety, but it could be in databases/postgresql/ , devops/deployments/ , api/versioning/ , or nowhere because you saved it somewhere temporary. Topic folders force you to decide where knowledge belongs before you understand its context. PARA delays that decision — instead of asking what something is about, it asks what you are currently doing with it. The Four Buckets Projects A project is active, time-bound work with a defined outcome. For engineers, projects are things like: Migrate billing service to queue v2 Upgrade PostgreSQL from 14 to 16 Write architecture decision record for auth service redesign Implement rate limiting on public API Publish article about distributed tracing Every project has a c

2026-06-21 原文 →
AI 资讯

1.4.10 Planner Hook: When It Fires, How to Use It

Everything from 1.4.1 through 1.4.9 happened inside a single function, standard_planner() . Building paths, costing them, searching for a join order, estimating cardinality from statistics: all of it runs inside that one function. Yet PostgreSQL does not call standard_planner() directly. It puts another function, planner() , one step ahead of it, and has planner() call standard_planner() . And planner() can be made to call some other function instead of standard_planner() . That replacement is what the planner hook enables. When pg_stat_statements measures per-query planning time, or pg_hint_plan rewrites a plan according to hints, it all goes through this hook. Let's look at how PostgreSQL provides a way to observe or change planning behavior without touching a single line of the core, and how external code plugs into it. All planner() does is check the hook The body of planner() is essentially this. if ( planner_hook ) result = ( * planner_hook ) ( parse , query_string , cursorOptions , boundParams ); else result = standard_planner ( parse , query_string , cursorOptions , boundParams ); planner_hook is a global function pointer. Its default value is NULL , in which case standard_planner() is called right away. A plain PostgreSQL build always takes this path: planner_hook is empty, so the incoming query goes straight to standard_planner() . The key here is the type of planner_hook . typedef PlannedStmt * ( * planner_hook_type ) ( Query * parse , const char * query_string , int cursorOptions , ParamListInfo boundParams ); This signature is identical, down to the character, to that of planner() and standard_planner() . It takes the same Query and returns the same PlannedStmt (the execution plan). So external code only has to write a planner function matching this type and store its address in planner_hook . Let's call this function, written by external code to register in planner_hook , a custom planner function. The moment its address is stored, every planning reque

2026-06-21 原文 →
AI 资讯

PostgreSQL Indexing Deep Dive - Choosing the Right Index

In the earlier posts of this series, we looked at practical query tuning tips and how to read and interpret query plans . A recurring theme in both was: "add an index here." But "add an index" is a bit like saying "use the right tool" — the interesting part is which one. PostgreSQL ships with several index types, each tuned for a different kind of data and query. Picking the wrong one means PostgreSQL quietly ignores your index and goes back to a sequential scan. In this post, we'll walk through the main index types, when each shines, and the special index variations (composite, partial, covering, expression) that often matter more than the type itself. Setting the Scene: Schema and Sample Data We'll reuse the same schema from the previous posts, with one small addition — a metadata JSONB column and a tags array on orders , so we can explore the more exotic index types. CREATE TABLE customers ( id SERIAL PRIMARY KEY , customer_name VARCHAR ( 255 ), email VARCHAR ( 255 ), created_at TIMESTAMPTZ DEFAULT NOW () ); CREATE TABLE orders ( id SERIAL PRIMARY KEY , customer_id INT REFERENCES customers ( id ), order_date TIMESTAMPTZ DEFAULT NOW (), total_amount NUMERIC ( 10 , 2 ), status VARCHAR ( 20 ), tags TEXT [], metadata JSONB ); -- Insert sample customers INSERT INTO customers ( customer_name , email ) SELECT 'Customer ' || i , 'customer' || i || '@example.com' FROM generate_series ( 1 , 1000000 ) AS s ( i ); -- Insert sample orders INSERT INTO orders ( customer_id , order_date , total_amount , status , tags , metadata ) SELECT ( RANDOM () * 1000000 ):: INT , NOW () - interval '1 day' * ( RANDOM () * 365 ):: int , ( RANDOM () * 500 + 20 ), ( ARRAY [ 'pending' , 'shipped' , 'delivered' , 'cancelled' ])[ FLOOR ( RANDOM () * 4 + 1 )], ARRAY [( ARRAY [ 'gift' , 'priority' , 'fragile' , 'bulk' ])[ FLOOR ( RANDOM () * 4 + 1 )]], jsonb_build_object ( 'channel' , ( ARRAY [ 'web' , 'mobile' , 'store' ])[ FLOOR ( RANDOM () * 3 + 1 )]) FROM generate_series ( 1 , 1000000 ) AS s ( i

2026-06-21 原文 →
AI 资讯

Show OS: Universal Uploader – Zero-dependency, stream-based file uploading with transparent XHR fallback

Hey everyone, I wanted to share an open-source library I’ve been developing to solve a persistent issue in frontend file ingestion: handling large-file uploads efficiently without blocking the main thread, consuming excessive client-side memory, or introducing heavy npm dependencies. The core architecture leverages Fetch Duplex streams combined with Web Streams API to achieve constant memory usage during large file transfers. For browsers lacking full duplex stream support (such as Safari), it seamlessly switches to an automated chunked XHR fallback at runtime. ⚙️ Core Architecture & Features Constant Memory Footprint: Streams large chunks sequentially using Fetch duplex streaming where supported. Intelligent Runtime Fallback: Detects capabilities instantly and falls back to a robust, chunked XMLHttpRequest pipeline to ensure cross-browser compatibility (including Safari). Resilient Lifecycle Management: Built-in hooks for pause, resume, manual abort, and automated chunk-level retries with a configurable exponential backoff algorithm. Zero Dependencies & Tree-shakeable: Written entirely in vanilla TypeScript with no external runtime dependencies (npm install u/universal-uploader/core). The architecture is highly modular, ensuring that unused upload strategies are completely tree-shaken during compilation. React Primitive Included: Ships with a declarative React hook that maps the entire upload lifecycle to state primitives without causing redundant re-renders. 🛠️ Why Existing Solutions Didn't Fit Most mainstream uploading libraries either rely on heavy multi-part form encodings that require buffering files entirely into browser memory, or pull in heavy polyfill architectures that bloating the initial bundle size. I designed this to isolate the transport layer logic via a composition-based approach, separating the stream controller from the network client. To ensure deterministic behavior, the codebase is fully covered by 127 integration/unit tests validating network

2026-06-21 原文 →
AI 资讯

Building a no-root Android automation app taught me that trust is harder than features

I’m building ScriptTap, a no-root Android automation app for user-controlled phone workflows. The app lets people create scripts with taps, swipes, routines, screen-aware checks, OCR/text detection, image/pixel checks, variables, logic, and AI-assisted script creation. The technical side is hard, but the trust side may be harder. ScriptTap needs Android Accessibility permission because user-authored input automation requires it. That is a powerful permission. I do not want to minimize it, hide it behind vague onboarding copy, or expect people to click through without understanding what they are enabling. That creates a product-design problem. If the copy is too soft, it feels dishonest. If the copy is too warning-heavy, a legitimate automation tool can feel suspicious before the user even understands what it does. The explanation I am trying to make clear is: ScriptTap is no-root. Scripts are created and controlled by the user. Screen capture is user-controlled. It does not bypass Android permissions, lock screens, app security, or consent flows. Accessibility is required for overlay/input automation, so users should understand why it is being requested. The short version I keep coming back to is: ScriptTap uses Accessibility so your scripts can interact with the screen the way you tell them to. This is a powerful permission. You should only enable it if you understand and trust what the app is doing. For developers who have built apps with sensitive permissions: How did you explain the permission without either hiding the risk or scaring users away from a legitimate feature?

2026-06-21 原文 →
AI 资讯

The Botfather: Building Your First Crypto Trading Bot

The Quest Begins (The "Why") Honestly, I was tired of staring at charts at 2 a.m., trying to catch that perfect entry while my coffee went cold. I’d set a manual alert, jump onto the exchange, click “buy”, and then second‑guess myself as the price slipped away. It felt like I was playing a never‑ending game of Whac‑A‑Mole, and I kept losing the mole. One night, after yet another missed opportunity, I thought: What if I could offload the repetitive bits to a script? Not a fancy AI that predicts the future—just a simple bot that watches the market, checks a condition, and places an order when the condition is met. If I could automate the boring part, I could focus on strategy, learning, and maybe even get some sleep. That was the dragon I wanted to slay: the exhaustion of manual trading. The Revelation (The Insight) The big “aha!” moment came when I realized I didn’t need to build a high‑frequency trading engine from scratch. There are solid, well‑tested libraries that handle the messy bits—authentication, rate limits, WebSocket connections—so I could concentrate on the logic. Using CCXT (a unified crypto exchange library) and a touch of asyncio , I could write a bot that: Connects to an exchange (I used Binance’s testnet so I wouldn’t lose real money). Polls the ticker for a symbol at a reasonable interval. Checks a simple condition—like “price > 20 % above the 20‑period moving average”. Places a market order if the condition holds, then waits for the next cycle. It felt like Neo dodging bullets in The Matrix when the bot finally executed a trade without crashing or getting rate‑limited. The relief was genuine: I could now let the code do the watching while I worked on the next idea. Wielding the Power (Code & Examples) The Struggle – A Naïve Loop My first attempt was a blocking while True loop with time.sleep . It looked harmless, but it had two nasty traps: Trap #1 – No error handling. A network hiccup would raise an exception and kill the whole script. Trap #2 – I

2026-06-21 原文 →
AI 资讯

How I Built a Counter Program in Anchor and Learned to Trust My Tests

I spent a week building a counter program in Anchor — the Rust framework for writing Solana programs. By the end I had two instructions, one authorization constraint, and a test suite I could actually trust. Here is what I built, how I tested it, and the moment I proved the tests were real. Start Here: The Accounts Struct If you come from Web2, this is the part that looks the strangest: #[derive(Accounts)] pub struct Initialize { #[account( init, payer = authority, space = 8 + Counter::INIT_SPACE, )] pub counter : Account , #[account(mut)] pub authority : Signer , pub system_program : Program , } In a Web2 backend, your handler receives a request object and talks to a database. On Solana, there is no database; there are accounts. Every account your instruction needs to read or write must be declared upfront, before the handler runs. Anchor validates them before your code ever executes. Here is what each field does: counter — the account being created. The init constraint tells Anchor to make a CPI to the System Program, allocate 8 + Counter::INIT_SPACE bytes, and fund it from authority . The 8 is for the discriminator Anchor stamps on every account so the program can later verify "this is mine." authority — the wallet signing and paying for the transaction. mut because its SOL balance is decreasing to fund the new account. system_program — required any time you create accounts. Anchor checks that the address matches the real System Program. The accounts struct is the schema. The handler is the logic. The Handlers pub fn initialize ( ctx : Context ) -> Result { let counter = & mut ctx .accounts.counter ; counter .authority = ctx .accounts.authority .key (); counter .count = 0 ; Ok (()) } ctx.accounts gives you typed access to every account declared in the struct. The handler is short because Anchor already did the hard work: allocating the account, checking the signer, paying the rent. Your code just sets the initial values. pub fn increment ( ctx : Context ) -> Resu

2026-06-21 原文 →
AI 资讯

How I Built CarbonCompass with Google Antigravity — A Personal Sustainability Coach, Not Just a Calculator

Most carbon footprint apps do the same thing: Quiz → "Your footprint is 120 kg CO₂/week" → Generic tips → User never returns. That's not a coaching experience. That's a guilt trip with no follow-through. For PromptWars Virtual — Challenge 3 (Carbon Footprint Awareness & Reduction), I built CarbonCompass with a different premise: Not just measure. Guide. Live demo: https://prompt-wars-virtual-hackathon-8u1kxxwh1-mithunvisveshs-projects.vercel.app/ The Problem with Existing Carbon Tools I started by looking at what already exists — Capture, Klima, JouleBug. Each of them calculates a footprint accurately. But they all fail at the same step: the recommendation layer. "Install solar panels." "Buy an EV." "Go vegan." These are structurally correct but useless for a hostel student in Chennai who travels by bus and eats at the mess. They're recommendations designed for a demographic that already has money and flexibility. CarbonCompass is built around two real Indian users: Aditi — a college student in Chennai. Bus commute, hostel mess food, shared room electricity. Her biggest carbon lever is food waste, not transport. Rohan — a tech professional in Bengaluru. Petrol car + scooter commute, air-conditioned 2BHK, frequent food delivery. His biggest lever is home energy, not diet. The same app, two users with different lifestyles receive coaching tailored to their highest-impact opportunities. That's the core product promise. The Architectural Decision That Made Everything Work Before writing a single line of code, I ran this prompt in Google Antigravity's Plan Mode: You are a senior product architect. Before coding: Generate user personas Design a SINGLE shared calculation module that the Dashboard, Impact Simulator, and AI Coach all call with the same inputs Create the data schema Propose page architecture Flag risks for a one-week build Do not write code yet. Create an Implementation Plan. The agent produced a full Implementation Plan artifact — a structured document I cou

2026-06-21 原文 →