Terms starting with "D"
Deprecation Notices & Migration Strategy
PHP 5.0+
1
E_DEPRECATED warnings signal features removed in the next PHP major version — treating them as errors in CI prevents upgrade blockers from accumulating.
6mo ago
PHP intermediate
Division by Zero & DivisionByZeroError
PHP 7.0+
PHP 7+ throws DivisionByZeroError for intdiv() and modulo with zero — but the / operator returns false or INF instead of throwing.
6mo ago
PHP beginner
Double URL Encoding Bypass
PHP 4.0+
Filters operating on URL-decoded input miss double-encoded payloads — %2527 decodes to %27 which decodes to ' — always decode completely before filtering.
6mo ago
Security advanced
DOM Manipulation
ES5
2
querySelector, createElement, innerHTML — reading and modifying PHP-rendered HTML from JavaScript.
6mo ago
JavaScript beginner
Data Mesh Architecture
Decentralised data architecture where domain teams own and publish their data as products — replacing centralised data lakes that create engineering bottlenecks.
6mo ago
Architecture advanced
Database Replication
PHP 5.0+
2
Copying data from one database server to replicas — synchronous replication guarantees zero data loss, asynchronous is faster but risks losing recent writes on failure.
6mo ago
Database intermediate
Database Seeding & Fixture Management
PHP 5.0+
1
Populating databases with consistent, reproducible test and development data — using factories, seeders, and fixtures to create realistic scenarios without manual data entry.
6mo ago
General intermediate
Database Triggers
PHP 5.0+ Stored procedures that fire automatically on INSERT, UPDATE, or DELETE — useful for audit logs and enforcing constraints, but dangerous when they become hidden business logic.
6mo ago
Database intermediate
Dead Condition
PHP 5.0+
A boolean condition that is always true or always false due to logic errors, making the branch either always execute or never execute.
6mo ago
Code Quality intermediate
Dependency Audit & CVE Scanning
PHP 5.0+
1
Automated scanning of project dependencies for known vulnerabilities (CVEs) — composer audit, npm audit, and tools like Snyk run in CI to catch vulnerable packages before deployment.
6mo ago
General intermediate
Dependency Confusion Attack
PHP 5.0+
An attacker publishes a public package with the same name as a private internal package — package managers may fetch the malicious public version instead of the private one.
6mo ago
Security advanced
Dependency Management Philosophy
PHP 5.3+
Every dependency is a liability — prefer few well-maintained packages; pin versions via composer.lock; audit regularly.
6mo ago
General intermediate
Deserialization Gadget Chains
PHP 5.0+
PHP object injection exploits that chain existing class methods (__wakeup, __destruct, __toString) to achieve remote code execution when unserialize() processes attacker-controlled data.
6mo ago
Security advanced
Dict & Set Comprehensions
Python 2.7+
Python's concise syntax for building dicts, sets, and lists in a single expression — replacing verbose for-loop accumulation patterns.
6mo ago
Python beginner
Disjoint Set / Union-Find
A data structure tracking which elements belong to the same group — supporting near-O(1) union and find operations. Used for network connectivity, Kruskal's MST, and cycle detection.
6mo ago
Data Structures advanced
Divide and Conquer
1
Recursively break a problem into smaller subproblems, solve each independently, and combine results — the strategy behind mergesort, quicksort, binary search, and FFT.
6mo ago
Algorithms intermediate
Docker Multi-Stage Builds
PHP 5.0+ Dockerfile builds using multiple FROM stages — build dependencies (Composer, Node, test tools) in earlier stages, copy only production artifacts to the final minimal image.
6mo ago
DevOps intermediate
Document Stores
PHP 7.0+
2
Databases that store semi-structured documents (JSON/BSON) — MongoDB, CouchDB — flexible schema, nested data, and horizontal scaling at the cost of no joins and eventual consistency.
6mo ago
Database intermediate
Domain Model Pattern
2
An object model of the domain that incorporates both behaviour and data — entities with methods expressing domain operations rather than just data containers.
6mo ago
Code Quality advanced
DSN Security & Connection String Secrets
PHP 5.0+
Database credentials in connection strings must never be hardcoded — use environment variables or secrets managers, least-privilege users, and never log DSNs.
6mo ago
Database intermediate