MySQL online course

Tables and types

Pick column types that will not fight you in a year.

CREATE TABLE device (
  id INT UNSIGNED NOT NULL AUTO_INCREMENT,
  hostname VARCHAR(64) NOT NULL,
  mgmt_ip VARCHAR(45),
  last_seen DATETIME,
  PRIMARY KEY (id),
  UNIQUE KEY uq_hostname (hostname)
);

Use INT / BIGINT for counts and ids, VARCHAR for short strings, TEXT for long bodies, and DATETIME or TIMESTAMP for events. Store IPv6-capable addresses in a string wide enough for them, or use VARBINARY if you will query them as bytes.