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1DROP TABLE IF EXISTS junctions;
2DROP TABLE IF EXISTS stations;
3DROP TABLE IF EXISTS routes;
4
5CREATE TABLE routes (
6    code INT NOT NULL PRIMARY KEY,
7    company_code INT NOT NULL,
8    name VARCHAR(100) NOT NULL
9);
10CREATE TABLE stations (
11    code INT NOT NULL PRIMARY KEY,
12    route_code INT NOT NULL,
13    group_code INT NOT NULL,
14    name VARCHAR(100) NOT NULL,
15    priority INT,
16    FOREIGN KEY(route_code) REFERENCES routes(code)
17);
18CREATE TABLE junctions (
19    route_code INT NOT NULL,
20    station_from INT NOT NULL,
21    station_to INT NOT NULL,
22    FOREIGN KEY(route_code) REFERENCES routes(code),
23    FOREIGN KEY(station_from) REFERENCES stations(code),
24    FOREIGN KEY(station_to) REFERENCES stations(code)
25);