Terms starting with "M"
MySQL JSON Column Type
A native JSON storage type introduced in MySQL 5.7 that validates, indexes, and queries JSON documents with dedicated functions.
6mo ago
Database intermediate
MySQL LIMIT and OFFSET Pagination
1
LIMIT restricts result row count; OFFSET skips rows for pagination — but OFFSET-based pagination degrades on large tables.
6mo ago
Database intermediate
MySQL NULL Handling
NULL in SQL represents an unknown value — it is not zero, not empty string, and comparisons with = NULL are always false.
6mo ago
Database beginner
MySQL Numeric Types
INT, BIGINT, DECIMAL, FLOAT, DOUBLE — the right type prevents overflow, precision loss, and money calculation bugs.
6mo ago
Database beginner
MySQL Query Cache (Deprecated)
A server-side cache for SELECT results removed in MySQL 8.0 — it caused severe scalability issues under concurrent writes.
6mo ago
Database intermediate
MySQL String Types: VARCHAR vs TEXT vs CHAR
CHAR is fixed-length, VARCHAR is variable-length up to 65,535 bytes, TEXT variants store large content — each with different indexing and storage behaviour.
6mo ago
Database beginner
MySQL Subqueries
A query nested inside another — useful for filtering and deriving values, but correlated subqueries re-execute per outer row and can be O(n²).
6mo ago
Database intermediate
Multimodal AI
AI models that process and generate across multiple input or output modalities — text, images, audio, and video — within a single unified architecture.
6mo ago
AI / ML intermediate
match Expression (PHP 8.0)
PHP 8.0+
PHP 8.0's match is a stricter switch — uses strict (===) comparison, each arm is an expression (not statements), returns a value, and throws UnhandledMatchError if no arm matches.
6mo ago
PHP beginner
mb_string — Multibyte String Functions
PHP 4.0+
2
PHP's native string functions operate on bytes, not characters. The mb_string extension provides mb_strlen(), mb_substr(), mb_strtolower() and 100+ equivalents that correctly handle multibyte encodings like UTF-8.
6mo ago
PHP intermediate
mcrypt Deprecation — Migrate to OpenSSL
PHP 5.0+
mcrypt was deprecated in PHP 7.1 and removed in PHP 7.2 — migrate all encryption to OpenSSL (openssl_encrypt) or libsodium (sodium_crypto_secretbox).
6mo ago
PHP intermediate
Memory Barriers & Visibility
1
Memory barriers (fences) force the CPU and compiler to complete memory operations in order — ensuring changes made by one thread are visible to others at the right time.
6mo ago
Concurrency advanced
Memory Exhaustion
PHP 4.0+
3
PHP's Allowed Memory Size Exhausted fatal error — caused by loading too much data into memory at once, unbounded loops accumulating objects, or memory leaks in long-running processes.
6mo ago
PHP intermediate
Message Broker
3
A message broker is middleware that receives, routes, and delivers messages between producers and consumers — decoupling services and enabling async communication at scale.
6mo ago
Messaging intermediate
Message Idempotency
1
An idempotent message handler produces the same result whether called once or many times — essential for at-least-once delivery where duplicates are expected.
6mo ago
Messaging intermediate
Message Ordering Guarantees
3
Message ordering is only guaranteed within a single Kafka partition or RabbitMQ queue — multiple partitions or consumers break FIFO order across the full topic.
6mo ago
Messaging intermediate
Message Queue
5
A durable buffer that decouples the component producing work (producer) from the component processing it (consumer), enabling async processing, load levelling, and retry logic without direct coupling.
6mo ago
Messaging intermediate
Message Queue Patterns
Core messaging patterns — competing consumers, scatter-gather, request-reply, message filter, and routing slip — solve recurring distributed communication challenges.
6mo ago
Messaging intermediate
Message Serialization (Avro/Protobuf)
Binary serialization formats (Avro, Protobuf, MessagePack) are faster and smaller than JSON for high-throughput messaging — with schema evolution support for Avro.
6mo ago
Messaging intermediate
Method Chaining Pitfalls & Alternatives
Method chaining (fluent interfaces) improves readability for builders but creates debugging difficulties, encourages temporal coupling, and can hide null returns.
6mo ago
Code Quality intermediate