Relational database design book

On Sun, 14 Dec 2008, Michael Hall wrote:

I'm wondering if anyone can recommend a good general book on relational database design.
...

Mick,

I highly recommend all the books by Joe Celko. He's been writing on
database issues for at least 20 years and communicates very well. I know
that he has a book that covers data normalization[1]There are several steps one undertakes to determine which attributes belong together in a table. When there is no duplication and referential integrity is ensured you'll have a stable and useful database schema that's easy to maintain. and that's probably
what you want to re-learn. His other topics are extremely helpful, too.

For an outstanding book about SQL (recommended to me by Joe when I wrote
to him about a source for knowledge of time-based databases[2]Strangely enough -- to me, at least -- the lack of full support for date- and time-based SQL in database tools such as PostgreSQL is puzzling. Virtually all business-related databases (think accounting systems as a prime example) depend on dates. So do many scientific databases.), read Rick
van der Laans's "Introduction to SQL, 4th Edition." It's a very large book
chock full of detailed information written very well.

Rich

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[1]: There are several steps one undertakes to determine which attributes belong together in a table. When there is no duplication and referential integrity is ensured you'll have a stable and useful database schema that's easy to maintain.
belong together in a table. When there is no duplication and referential
integrity is ensured you'll have a stable and useful database schema that's
easy to maintain.

[2]: Strangely enough -- to me, at least -- the lack of full support for date- and time-based SQL in database tools such as PostgreSQL is puzzling. Virtually all business-related databases (think accounting systems as a prime example) depend on dates. So do many scientific databases.
date- and time-based SQL in database tools such as PostgreSQL is puzzling.
Virtually all business-related databases (think accounting systems as a
prime example) depend on dates. So do many scientific databases.

rshepard@appl-ecosys.com (Rich Shepard) writes:

[2] Strangely enough -- to me, at least -- the lack of full support for
date- and time-based SQL in database tools such as PostgreSQL is puzzling.
Virtually all business-related databases (think accounting systems as a
prime example) depend on dates. So do many scientific databases.

The support for temporality in PostgreSQL seems above average as far
as I can see...

PostgreSQL has pretty nice time types between the timestamptz type and
interval.

What strikes me as being missing is the ability to create
temporally-aware foreign keys.

That is, suppose the schema is:

create table1 (
nearly_pk integer not null,
from_date timestamptz not null default now(),
to_date timestamptz not null default 'Infinity',
constraint dating_t1 check (from_date < to_date)
-- probably some other data...
);

I'd like to be able to do two more things:

a) Treat the date range as part of the primary key (which isn't
forcibly hard),

b) Have references to table1 that point to the time range for the
"nearly_pk" value but which are a little more liberal with the dates.

create table2 (
t2pk integer primary key,
nearly_pk integer not null,
from_date timestamptz not null default now(),
to_date timestamptz not null default 'Infinity',
-- And have a "foreign key" that requires that
-- for tuple in table2 the combination (nearly_pk, from_date, to_date)
-- is *contained* by relevant ranges of (nearly_pk, from_date, to_date)
-- on table1
foreign key (nearly_pk) references
table1(nearly_pk) with temporal (table2.from_date, table2.to_date)
contained_by (table1.from_date, table1.to_date)
);

I don't think the syntax there is necessarily quite right; I'm just
hoping to express the idea successfully.

I could presumably do this with a trigger; have been trying to avoid
that thus far.

There are, of course, other ways of treating temporality; that is part
of why it's early to treat this approach as worth putting into syntax.
--
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http://cbbrowne.com/info/finances.html
"When the grammar checker identifies an error, it suggests a
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On 15/12/2008 15:09, Chris Browne wrote:

PostgreSQL has pretty nice time types between the timestamptz type and
interval.

Yeah... I've often gotten really frustrated trying to do date- and
time-related stuff in PHP - it's much easier to get PG to do it instead. :-)

Ray.

------------------------------------------------------------------
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rod@iol.ie
Galway Cathedral Recitals: http://www.galwaycathedral.org/recitals
------------------------------------------------------------------

It might be useful to look at the capabilities of the Informix Timeseries Datablade

(http://www-01.ibm.com/software/data/informix/blades/)

if you want to look at ways of enhancing the temporal data capabilities of Postgres.

Cheers,

Brent

Brent Wood
DBA/GIS consultant
NIWA, Wellington
New Zealand

Chris Browne <cbbrowne@acm.org> 12/16/08 10:05 AM >>>

rshepard@appl-ecosys.com (Rich Shepard) writes:

[2] Strangely enough -- to me, at least -- the lack of full support for
date- and time-based SQL in database tools such as PostgreSQL is puzzling.
Virtually all business-related databases (think accounting systems as a
prime example) depend on dates. So do many scientific databases.

The support for temporality in PostgreSQL seems above average as far
as I can see...

PostgreSQL has pretty nice time types between the timestamptz type and
interval.

What strikes me as being missing is the ability to create
temporally-aware foreign keys.

That is, suppose the schema is:

create table1 (
nearly_pk integer not null,
from_date timestamptz not null default now(),
to_date timestamptz not null default 'Infinity',
constraint dating_t1 check (from_date < to_date)
-- probably some other data...
);

I'd like to be able to do two more things:

a) Treat the date range as part of the primary key (which isn't
forcibly hard),

b) Have references to table1 that point to the time range for the
"nearly_pk" value but which are a little more liberal with the dates.

create table2 (
t2pk integer primary key,
nearly_pk integer not null,
from_date timestamptz not null default now(),
to_date timestamptz not null default 'Infinity',
-- And have a "foreign key" that requires that
-- for tuple in table2 the combination (nearly_pk, from_date, to_date)
-- is *contained* by relevant ranges of (nearly_pk, from_date, to_date)
-- on table1
foreign key (nearly_pk) references
table1(nearly_pk) with temporal (table2.from_date, table2.to_date)
contained_by (table1.from_date, table1.to_date)
);

I don't think the syntax there is necessarily quite right; I'm just
hoping to express the idea successfully.

I could presumably do this with a trigger; have been trying to avoid
that thus far.

There are, of course, other ways of treating temporality; that is part
of why it's early to treat this approach as worth putting into syntax.
--
output = ("cbbrowne" "@" "acm.org")
http://cbbrowne.com/info/finances.html
"When the grammar checker identifies an error, it suggests a
correction and can even makes some changes for you."
-- Microsoft Word for Windows 2.0 User's Guide, p.35:

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