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.Elphick@lfix.co.uk
Isle of Wight http://www.lfix.co.uk/oliver
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GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C
========================================
"If my people, which are called by my name, shall
humble themselves, and pray, and seek my face, and
turn from their wicked ways; then will I hear from
heaven, and will forgive their sin, and will heal
their land." II Chronicles 7:14
