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“What is a port?” · “Why is my code erroring?”
Ask me anything about your lessons or your code.
“What is a port?” · “Why is my code erroring?”
Plain files crack under two writers, million-row lookups, and consistency. A database is the tool built for that job: tables, rows, keys, and SQL.
What a Database Is
Plain files crack under two writers, million-row lookups, and consistency. A database is the tool built for that job: tables, rows, keys, and SQL.
Querying With SELECT
SELECT is how you read data back out of a table: the exact shape, a real books table, and why naming columns beats SELECT star.
Filtering and Sorting
A whole table is rarely the question. WHERE, ORDER BY, and LIMIT pull just the rows that matter, in the order you want them.
Relationships and Joins
Real data lives in separate tables on purpose; a JOIN matches their keys and pulls one answer from several tables at once.
Changing Data
INSERT, UPDATE, and DELETE change the tables joins read from, and one missing WHERE can rewrite every row.