some plpgsql stuff

sql/create_tables.sql

@@ -2,24 +2,28 @@ CREATE OR REPLACE PROCEDURE create_tables() AS $$
 	DROP TABLE IF EXISTS artist_website;
 	DROP TABLE IF EXISTS website;
 	DROP TABLE IF EXISTS artist;
-	
+
 	CREATE TABLE IF NOT EXISTS artist (
 		id serial PRIMARY KEY,
-		name text NOT NULL
+		name text NOT NULL,
+		CONSTRAINT a_name UNIQUE(name)
 	);
-	
+
 	CREATE TABLE IF NOT EXISTS website (
 		id serial PRIMARY KEY,
-		name text NOT NULL
+		name text NOT NULL,
+		CONSTRAINT w_name UNIQUE(name)
 	);
-	
+
 	CREATE TABLE IF NOT EXISTS artist_website (
 		id serial PRIMARY KEY,
 		url text NOT NULL,
 		folder_path text,
 		website_id integer,
 		artist_id integer,
+		CONSTRAINT aw_url UNIQUE(url),
+		CONSTRAINT aw_folder_path UNIQUE(folder_path),
 		CONSTRAINT aw_artist FOREIGN KEY (artist_id) REFERENCES artist (ID),
 		CONSTRAINT aw_website FOREIGN KEY (website_id) REFERENCES website (ID)
 	);
-$$ LANGUAGE SQL;
+$$ LANGUAGE SQL;