Greetings, Maxim!
At 22.06.2001, 09:20, you wrote:
MM> I am not a very great PostgreSQL user, but I know mySQL. In mySQL we have
MM> SET and ENUM.
MM> I now need something like this in PostgreSQL.
Trust me: you don't. These are ugly crutches to circumvent mySQL's
complete lack of referential integrity. These are unportable, too.
`Emulating` the SET:
------------------------------------------------
create table foo (
foo_id ...,
foo1 ...,
foo2 ...,
primary key (foo_id)
)
create table foo_set_values (
set_id ...,
set_value ...,
primary key (set_id)
)
create table foo_set (
foo_id ...,
set_id ...,
primary key (foo_id, set_id),
foreign key (foo_id) references foo,
foreign key (set_id) references foo_set_values
)
------------------------------------------------
`Emulating` the ENUM (with lookup table)
------------------------------------------------
create table bar_enum (
enum_id ...,
enum_value ...,
primary key (enum_id)
)
create table bar (
bar_id ...,
bar1 ...,
bar2 ...,
enum_id ...,
primary key (bar_id),
foreign key (enum_id) references bar_enum
)
------------------------------------------------
`Emulating` the ENUM (with CHECK)
------------------------------------------------
create table bar (
bar_id ...,
bar1 ...,
bar2 ...,
bar_enum ... CHECK bar_enum IN ('one', 'two', 'three'),
primary key (bar_id)
)
------------------------------------------------
These ARE portable. To anywhere except mySQL.
--
Yours, Alexey V. Borzov, Webmaster of RDW.ru
