Creating SQL table, foreign_key confusion
Question
One question, I have supervisor set as foreign key. He collect information through Activity Participant and take it from person ID.
Question:
How should I create the Activity table? what do I have to write down about supervisor?
CREATE TABLE activity
(
act_id VARCHAR(8) CONSTRAINT activity_pk PRIMARY KEY,
act_type VARCHAR2(20),
act_desc VARCHAR2(30),
act_date DATE,
mor_aft VARCHAR2(9),
);
1 answers
solution1
2 ACCPTED 2013-03-10 15:07:32
A foreign key must reference a unique key of the referenced table. Either the table's primary key, or else a secondary unique key.
CONSTRAINT activity_sup_fk FOREIGN KEY (act_supVisor)
REFERENCES person(Person_id)
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.
Related Question
SQL latest record per foreign_key
SQL: Order by a list of foreign_key numbers
Does rails association prevents a new record to be created like a foreign_key on a SQL create table would?
Confusion about SQL foreign key constraint when creating tables
Select from table 1 with foreign_key = x on table 2 where table 2 foreign key = Y on table 3
oracle sql, creating table with foreign key
FOREIGN_KEY constraint exception
creating sql table with foreign key error no:150
Percentage based on foreign_key
Creating a table with a foreign key
Related Tags