DDL

CREATE, ALTER, DROP, TRUNCATE and renaming database objects.

3 notes

Notes

CREATE defines the objects data lives in. Learn CREATE DATABASE, CREATE SCHEMA and CREATE TABLE, with column definitions and inline constraints.

SQL

ALTER changes a table that already holds data. Add and drop columns, change types, set defaults and manage constraints without losing rows.

SQL

Three ways to remove data, with very different consequences. Learn what each one destroys, what can be rolled back and what resets identity counters.