What is the difference of foreign key?

Started by 纪晓曦over 16 years ago2 messagesgeneral

sheepjxx@gmail.com

over 16 years ago

To be precise,

The difference between

create table a (
foreign key (id) referenced by b(name),
);

create table b(
id integer referenced by b(name),
);

serge.fonville@gmail.com

over 16 years ago

In reply to: 纪晓曦 (#1)

Re: What is the difference of foreign key?

Hi,

Read http://www.postgresql.org/docs/8.4/static/sql-createtable.html

REFERENCES *reftable* [ ( *refcolumn* ) ] [ MATCH *matchtype* ] [ ON
DELETE *action* ] [ ON UPDATE *action* ] (column constraint)
FOREIGN KEY ( *column* [, ... ] ) REFERENCES *reftable* [ ( *refcolumn* [,
... ] ) ] [ MATCH *matchtype* ] [ ON DELETE *action* ] [ ON UPDATE *action
* ] (table constraint)

HTH

Regards,

Serge Fonville

On Thu, Sep 24, 2009 at 4:18 PM, 纪晓曦 <sheepjxx@gmail.com> wrote:

To be precise,

The difference between

create table a (
foreign key (id) referenced by b(name),
);

create table b(
id integer referenced by b(name),
);

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