SQL · Theory

Rename Column

Theory

25/439

Rename Column

MySQL 8: ALTER TABLE students RENAME COLUMN marks TO score; Older: ALTER TABLE students CHANGE marks score INT; CHANGE requires the type again — easy to mistype.

Rename in the app too. ORM field names will break if you only change SQL.

Trap — CHANGE with the wrong type and silently converting data.

On the example next to this theory — Rename Column — aLTER TABLE changes structure without rebuilding the whole table.

Exam tip

ALTER TABLE students RENAME COLUMN marks TO score;

Rename Column — sample query

CREATE TABLE items (id INTEGER PRIMARY KEY, title TEXT);
ALTER TABLE items ADD COLUMN price REAL DEFAULT 0;
INSERT INTO items (id, title, price) VALUES (1, 'Pen', 10);
SELECT * FROM items;

Rename Column — aLTER TABLE changes structure without rebuilding the whole table.

Short notes

DefRENAME COLUMN (8+) or CHANGE (older).
RuleUpdate application code after a rename.
TrapCHANGE with a different type by mistake.

SQL · Theory

Rename Column

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Theory

25/439

Rename Column

MySQL 8: ALTER TABLE students RENAME COLUMN marks TO score; Older: ALTER TABLE students CHANGE marks score INT; CHANGE requires the type again — easy to mistype.

Rename in the app too. ORM field names will break if you only change SQL.

Trap — CHANGE with the wrong type and silently converting data.

On the example next to this theory — Rename Column — aLTER TABLE changes structure without rebuilding the whole table.

Exam tip

ALTER TABLE students RENAME COLUMN marks TO score;

Rename Column — sample query

CREATE TABLE items (id INTEGER PRIMARY KEY, title TEXT);
ALTER TABLE items ADD COLUMN price REAL DEFAULT 0;
INSERT INTO items (id, title, price) VALUES (1, 'Pen', 10);
SELECT * FROM items;

Rename Column — aLTER TABLE changes structure without rebuilding the whole table.

Short notes

DefRENAME COLUMN (8+) or CHANGE (older).
RuleUpdate application code after a rename.
TrapCHANGE with a different type by mistake.

Rename Column

Rename Column — sample query

Short notes

Questions

Rename Column

Rename Column — sample query

Short notes

Questions