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If we redo our URIs table as a "resources" table, with literals as well as URIs, we have some more options.
CREATE TABLE resources (
id INT AUTO_INCREMENT PRIMARY KEY, # PRIMARY = UNIQUE and NOT NULL
# either provide a uri
uri BLOB,
# or a literal_value, which might have a datatype and language
literal_value BLOB,
datatype INT,
language VARCHAR(5),
UNIQUE KEY (uri(64)) # length is just a tuning knob
);
INSERT INTO resources (uri) VALUES ('http://www.w3.org/1999/02/22-rdf-syntax-ns#type');
INSERT INTO resources (uri) VALUES ('http://www.w3.org/2000/10/swap/test/demo1/biology#Human');
INSERT INTO resources (uri) VALUES ('http://www.w3.org/2000/10/swap/test/demo1/biology#Dog');
INSERT INTO resources (uri) VALUES ('http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#name');
INSERT INTO resources (uri) VALUES ('http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#pet');
INSERT INTO resources (uri) VALUES ('http://www.w3.org/2000/10/swap/test/demo1/about-pat#pat');
INSERT INTO resources (uri) VALUES (NULL); # this is rover, who has no URI
INSERT INTO resources (literal_value) VALUES ('Pat Smith');
INSERT INTO resources (literal_value) VALUES ('Patrick Smith');
INSERT INTO resources (literal_value) VALUES ('Rover');
mysql> select * from resources;
+----+--------------------------------------------------------------+---------------+----------+----------+
| id | uri | literal_value | datatype | language |
+----+--------------------------------------------------------------+---------------+----------+----------+
| 1 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | NULL | NULL | NULL |
| 2 | http://www.w3.org/2000/10/swap/test/demo1/biology#Human | NULL | NULL | NULL |
| 3 | http://www.w3.org/2000/10/swap/test/demo1/biology#Dog | NULL | NULL | NULL |
| 4 | http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#name | NULL | NULL | NULL |
| 5 | http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#pet | NULL | NULL | NULL |
| 6 | http://www.w3.org/2000/10/swap/test/demo1/about-pat#pat | NULL | NULL | NULL |
| 7 | NULL | NULL | NULL | NULL |
| 8 | NULL | Pat Smith | NULL | NULL |
| 9 | NULL | Patrick Smith | NULL | NULL |
| 10 | NULL | Rover | NULL | NULL |
+----+--------------------------------------------------------------+---------------+----------+----------+
Then we can have a simple table of triples:
CREATE TABLE triples (
subject INT NOT NULL,
predicate INT NOT NULL,
object INT NOT NULL,
UNIQUE INDEX(subject, predicate, object),
INDEX(predicate, object),
INDEX(object, predicate)
);
INSERT INTO triples VALUES (6, 4, 8);
INSERT INTO triples VALUES (6, 4, 9);
INSERT INTO triples VALUES (7, 4, 10);
INSERT INTO triples VALUES (6, 1, 2);
INSERT INTO triples VALUES (7, 1, 3);
INSERT INTO triples VALUES (6, 5, 7);
mysql> select * from triples;
+---------+-----------+--------+
| subject | predicate | object |
+---------+-----------+--------+
| 6 | 1 | 2 |
| 6 | 4 | 8 |
| 6 | 4 | 9 |
| 6 | 5 | 7 |
| 7 | 1 | 3 |
| 7 | 4 | 10 |
+---------+-----------+--------+
mysql> select s.id, s.uri, p.uri as "predicate",
o.id, o.uri, o.literal_value as "lit"
from triples, resources as s, resources as p, resources as o
where s.id=triples.subject AND
p.id=triples.predicate AND
o.id=triples.object;
+----+---------------------------------------------------------+--------------------------------------------------------------+----+---------------------------------------------------------+---------------+
| id | uri | predicate | id | uri | lit |
+----+---------------------------------------------------------+--------------------------------------------------------------+----+---------------------------------------------------------+---------------+
| 6 | http://www.w3.org/2000/10/swap/test/demo1/about-pat#pat | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | 2 | http://www.w3.org/2000/10/swap/test/demo1/biology#Human | NULL |
| 6 | http://www.w3.org/2000/10/swap/test/demo1/about-pat#pat | http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#name | 8 | NULL | Pat Smith |
| 6 | http://www.w3.org/2000/10/swap/test/demo1/about-pat#pat | http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#name | 9 | NULL | Patrick Smith |
| 6 | http://www.w3.org/2000/10/swap/test/demo1/about-pat#pat | http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#pet | 7 | NULL | NULL |
| 7 | NULL | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | 3 | http://www.w3.org/2000/10/swap/test/demo1/biology#Dog | NULL |
| 7 | NULL | http://www.w3.org/2000/10/swap/test/demo1/friends-vocab#name | 10 | NULL | Rover |
+----+---------------------------------------------------------+--------------------------------------------------------------+----+---------------------------------------------------------+---------------+
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