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SELECT * FROM v$version;
| BANNER |
|---|
| Oracle Database 11g Express Edition Release 11.2.0.2.0 - 64bit Production |
| PL/SQL Release 11.2.0.2.0 - Production |
| CORE 11.2.0.2.0 Production |
| TNS for Linux: Version 11.2.0.2.0 - Production |
| NLSRTL Version 11.2.0.2.0 - Production |
CREATE TABLE user_ -- Oracle doesn't let you create a table called "user"
(
user_id INTEGER NOT NULL PRIMARY KEY,
user_name VARCHAR (25) NOT NULL
);
INSERT INTO user_ (user_id, user_name)
SELECT 1, 'user_1' FROM dual
UNION
SELECT 2, 'user_2' FROM dual;
2 rows affected
SELECT * FROM user_ ORDER BY user_id;
| USER_ID | USER_NAME |
|---|---|
| 1 | user_1 |
| 2 | user_2 |
CREATE TABLE message
(
message_id INTEGER NOT NULL PRIMARY KEY,
sender_id INTEGER,
message_text VARCHAR (100) NOT NULL,
FOREIGN KEY (sender_id) REFERENCES user_ (user_id)
);
INSERT INTO message
SELECT 1, 1, 'm1' FROM dual
UNION
SELECT 2, 1, 'm2' FROM dual
UNION
SELECT 3, 2, 'm3' FROM dual
UNION
SELECT 4, 2, 'm4' FROM dual;
4 rows affected
SELECT * FROM message;
| MESSAGE_ID | SENDER_ID | MESSAGE_TEXT |
|---|---|---|
| 1 | 1 | m1 |
| 2 | 1 | m2 |
| 3 | 2 | m3 |
| 4 | 2 | m4 |
INSERT INTO message VALUES (5, 56, 'mxxxx');
ORA-02291: integrity constraint (FIDDLE_SFUMLUOUAPJRGZRTEMCW.SYS_C00313901) violated - parent key not found