Re: Foreign key creation

edp wrote:
>How to create foreign key in Posgresql.

There are two ways, as shown below:

CREATE TABLE supplier (
id INTEGER PRIMARY KEY,
name TEXT
);

CREATE TABLE invoice (
invno SERIAL PRIMARY KEY,
supplier INTEGER NOT NULL
REFERENCES supplier(id)
ON UPDATE CASCADE
ON DELETE RESTRICT
DEFERRABLE,
...etc...
);

CREATE TABLE location (
id CHAR(2) PRIMARY KEY
name TEXT NOT NULL
);

CREATE TABLE supplier_location (
supplier INTEGER NOT NULL
REFERENCES supplier(id)
ON UPDATE CASCADE
ON DELETE RESTRICT
DEFERRABLE,
location CHAR(2) NOT NULL
REFERENCES location(id)
ON UPDATE CASCADE
ON DELETE RESTRICT
DEFERRABLE
);

CREATE TABLE delivery (
product VARCHAR(10),
supplier INTEGER,
location CHAR(2),
...etc...,
PRIMARY KEY (product, supplier, location),
FOREIGN KEY (supplier, location) REFERENCES supplier_location
ON UPDATE CASCADE
ON DELETE RESTRICT
MATCH FULL
DEFERRABLE
);
--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
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