foreign key constraint to multiple tables
От | Kevin McCarthy |
---|---|
Тема | foreign key constraint to multiple tables |
Дата | |
Msg-id | 4178da10708141426k75f64624ob8666ac6c8c465ed@mail.gmail.com обсуждение исходный текст |
Ответы |
Re: foreign key constraint to multiple tables
|
Список | pgsql-novice |
I have a table with a column that will join with one of several tables based on the value of another column. I'm not sure if this column can be set as a foreign key to any of these tables, may be simply bad design on my part. The item_type_id column of a record of 'A' will reference one of the 'type' table records depending upon what the value of the record's item_type column is.
Is there a way to set the item_type_id column in Table A as a foreign key to the other tables depending? Or would there be a better way to design this schema?
TIA
CREATE TABLE ABC(
id SERIAL PRIMARY KEY,
item_type character varying(10) NOT NULL,
item_type_id INTEGER
);
CREATE TABLE typeA(
typeA_id SERIAL PRIMARY KEY
);
CREATE TABLE typeB(
typeB_id SERIAL PRIMARY KEY
);
CREATE TABLE typeC(
typeC_id SERIAL PRIMARY KEY
);
--
Kevin McCarthy
kemccarthy1@gmail.com
Is there a way to set the item_type_id column in Table A as a foreign key to the other tables depending? Or would there be a better way to design this schema?
TIA
CREATE TABLE ABC(
id SERIAL PRIMARY KEY,
item_type character varying(10) NOT NULL,
item_type_id INTEGER
);
CREATE TABLE typeA(
typeA_id SERIAL PRIMARY KEY
);
CREATE TABLE typeB(
typeB_id SERIAL PRIMARY KEY
);
CREATE TABLE typeC(
typeC_id SERIAL PRIMARY KEY
);
--
Kevin McCarthy
kemccarthy1@gmail.com
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