Hi
If i have two foreign keys in a table which make up my primary key, do i actually write in the SQL that they are the primary keys?
I know you can't declare more than one primary key in a table, eg
CREATE TABLE FACILITIES(
venue_id INTEGER PRIMARY KEY REFERENCES VENUE NOT NULL,
facility_id INTEGER PRIMARY KEY REFERENCES FACILITY_TYPE NOT NULL
)
...so do i just reference them as foreign keys? :S
eg
CREATE TABLE FACILITIES(
venue_id INTEGER REFERENCES VENUE NOT NULL,
facility_id INTEGER REFERENCES FACILITY_TYPE NOT NULL
)
thanks in advance!create table facilities
( venue_id integer not null references venue
, facility_id integer not null references facility_type
, primary key (venue_id, facility_id)
)|||create table facilities
( venue_id integer not null references venue
, facility_id integer not null references facility_type
, primary key (venue_id, facility_id)
)
Ahh right, i see, so you have to define the primary key seperatly! - i have a 450+ page book on database design and it doesn't mention how to do that :mad: ...thanks again r937|||oh, it's gotta be in there somewhere!!
i cannot imagine a database book that overlooks a composite primary key
tell me, does it discuss how to implement a many-to-many relationship? what does the table in the middle look like?|||It tells you that you can create a primary key using two foreign keys (composite) and shows it in the ERD, but i couldn't seem to find an example on how to actually create it!|||too bad, eh -- well, now you know :)
and of course your database system's documentation would cover it in its CREATE TABLE syntax
Showing posts with label hiif. Show all posts
Showing posts with label hiif. Show all posts
Sunday, March 11, 2012
Subscribe to:
Posts (Atom)