Database terms
Where your data lives, breathes, and occasionally panics
Almost every application is, at its core, a system for reading and writing data. This category covers relational and non-relational databases, query optimisation, indexing strategies, transactions, normalisation, replication, and the CAP theorem trade-offs that dictate how distributed data behaves. Choosing and using the right database correctly is one of the highest-leverage skills in backend development.
MySQL AUTO_INCREMENT
A column attribute that automatically assigns sequential integer IDs on INSERT — the standard primary key pattern in MySQL.
1mo ago
database beginner
MySQL Date and Time Types
DATETIME, TIMESTAMP, DATE, TIME, and YEAR — each with different ranges, timezone handling, and storage sizes.
1mo ago
database beginner
MySQL ENUM Type
A column that accepts only predefined string values — stored efficiently as integers but with significant schema change pain.
1mo ago
database beginner
MySQL EXPLAIN
A MySQL query analysis command showing the execution plan — which indexes are used, how many rows are scanned, and where bottlenecks are.
1mo ago
database intermediate
MySQL FULLTEXT Search
A built-in MySQL search engine supporting natural language and boolean full-text queries on TEXT and VARCHAR columns.
1mo ago
database intermediate
MySQL GROUP BY and Aggregates
GROUP BY collapses rows with matching column values into one — aggregate functions (COUNT, SUM, AVG, MAX, MIN) compute values per group.
1mo ago
database intermediate
MySQL Index Types B-tree, FULLTEXT, SPATIAL, and HASH indexes — each optimised for different query patterns.
1mo ago
database intermediate
MySQL JOIN Types
INNER JOIN, LEFT JOIN, RIGHT JOIN, and CROSS JOIN — controlling which rows are included when combining tables.
1mo ago
database beginner
MySQL JSON Column Type
A native JSON storage type introduced in MySQL 5.7 that validates, indexes, and queries JSON documents with dedicated functions.
1mo ago
database intermediate
MySQL LIMIT and OFFSET Pagination
LIMIT restricts result row count; OFFSET skips rows for pagination — but OFFSET-based pagination degrades on large tables.
1mo 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.
1mo ago
database beginner
MySQL Numeric Types
INT, BIGINT, DECIMAL, FLOAT, DOUBLE — the right type prevents overflow, precision loss, and money calculation bugs.
1mo 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.
1mo 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.
1mo 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).
1mo ago
database intermediate