CREATE TABLE sensors(
id integer primary key AUTOINCREMENT,
sn numeric unique,
note varchar
);
CREATE TABLE data(
id integer primary key AUTOINCREMENT,
sn numeric,
ts numeric,
pq varchar, -- physical quantity
value varchar,
systemts DATETIME DEFAULT (strftime('%s','now'))
);
CREATE TABLE input (
id integer primary key AUTOINCREMENT,
sn varchar,
variable varchar,
value numeric,
type varchar
);
CREATE INDEX tsindex ON data (sn, pq, systemts);