Intermediate terms
Database Query Result Streaming
PHP 8.0+
2
Processing large result sets row-by-row without loading the entire dataset into memory - essential for PHP CLI scripts handling millions of rows.
1mo ago
database intermediate
Discriminated Unions
2.0
2
A union of types that each carry a shared literal field (the discriminant) allowing TypeScript to narrow exhaustively — the canonical way to model mutually exclusive states.
2mo ago
typescript intermediate
Dependency & Supply Chain Security
Protecting applications from malicious or vulnerable third-party packages — covering transitive dependencies, lock files, SRI hashes, CVE scanning, and supply chain attack vectors.
CWE-1357 OWASP A6:2021
2mo ago
security intermediate
Docker HEALTHCHECK
A Dockerfile instruction that defines how Docker tests whether a container is healthy — enabling automatic restart and load balancer removal on failure.
2mo ago
devops intermediate
Dead Code Elimination
PHP 7.4+
3
A compiler and static analysis optimisation that identifies and removes code that can never be executed or whose result is never used.
3mo ago
compiler intermediate
Database Connection Pooling
Connection pooling reuses a fixed set of database connections across requests — eliminating the 50–200ms connection overhead on every request and limiting DB connection count.
3mo ago
concurrency intermediate
Database Indexes
4
Data structures that allow the database engine to find rows matching a condition without scanning every row — the single most impactful performance optimisation available for read-heavy PHP applications.
3mo ago
database intermediate
Dead Letter Queue
1
A Dead Letter Queue (DLQ) captures messages that can't be processed — expired, malformed, or repeatedly failed — enabling later inspection and replay without losing data.
3mo ago
messaging intermediate
Deadlock
2
A deadlock occurs when two or more processes each hold a resource the other needs — both wait forever. Prevention requires consistent lock ordering or timeouts.
3mo ago
concurrency intermediate
DI Containers — PHP-DI, Symfony & Laravel Compared
PHP 7.4+
A Dependency Injection container automates wiring of class dependencies — instead of manually constructing objects and their dependencies, the container reads type hints and builds the full object graph. PHP-DI, Symfony's DIC, and Laravel's service container are the main options.
3mo ago
php intermediate
Distributed Tracing
1
Distributed tracing tracks a request as it flows through multiple services — each service adds a span to a shared trace, giving end-to-end visibility into latency and failures.
3mo ago
observability intermediate
DOMDocument & XPath in PHP
PHP 5.0+
PHP's DOMDocument extension parses HTML and XML into a traversable tree. Combined with DOMXPath, you can query the document with XPath expressions — far more powerful than regex for extracting data from HTML.
3mo ago
php intermediate
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.
3mo ago
php intermediate
Database Replication
PHP 5.0+
1
Copying data from one database server to replicas — synchronous replication guarantees zero data loss, asynchronous is faster but risks losing recent writes on failure.
3mo ago
database intermediate
Database Seeding & Fixture Management
PHP 5.0+
Populating databases with consistent, reproducible test and development data — using factories, seeders, and fixtures to create realistic scenarios without manual data entry.
3mo 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.
3mo 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.
3mo ago
quality intermediate
Dependency Audit & CVE Scanning
PHP 5.0+
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.
3mo ago
general intermediate
Dependency Management Philosophy
PHP 5.3+
Every dependency is a liability — prefer few well-maintained packages; pin versions via composer.lock; audit regularly.
3mo ago
general intermediate
Divide and Conquer
Recursively break a problem into smaller subproblems, solve each independently, and combine results — the strategy behind mergesort, quicksort, binary search, and FFT.
3mo ago
algorithms intermediate