One-byte integral type?

#1

Hello,

I see PostgreSQL doesn't have a real one-byte integral type, like
TINYINT. What do you use instead?

Karsten

#2

Karsten Wutzke wrote:

Quote:

I see PostgreSQL doesn't have a real one-byte integral type, like
TINYINT. What do you use instead?

That's right.
You could use "smallint" instead which only uses 2 bytes.
If you want to prevent larger values to be inserted,
you could use a check constraint.

Yours,
Laurenz Albe

#3

On 7 Sep., 10:38, "Laurenz Albe" <inv... (AT) spam (DOT) to.invalid> wrote:

Quote:

Karsten Wutzke wrote:
I see PostgreSQL doesn't have a real one-byte integral type, like
TINYINT. What do you use instead?

That's right.
You could use "smallint" instead which only uses 2 bytes.
If you want to prevent larger values to be inserted,
you could use a check constraint.

Yours,
Laurenz Albe

How do you ensure that a one-byte range type only occupies one byte?

Is it because of the SQL standard, that PostgreSQL doesn't have a one-
byte type, too?

Generally, I get the feeling the mainstream DBMS' around (PostgreSQL,
MySQL, Oracle, ...) don't like byte-wise types. Could it have to do
with two-byte memory alignment issues?

Karsten

#4

Karsten Wutzke, 07.09.2009 13:06:

Quote:

Generally, I get the feeling the mainstream DBMS' around (PostgreSQL,
MySQL, Oracle, ...) don't like byte-wise types. Could it have to do
with two-byte memory alignment issues?

What's the use for a single-byte datatype? Space consideration should not matter nowadays.

If you want to make sure the values are limited to a certain numeric range, then use a check constraint.

Thomas

#5

Karsten Wutzke wrote:

Quote:

I see PostgreSQL doesn't have a real one-byte integral type, like
TINYINT. What do you use instead?

That's right.
You could use "smallint" instead which only uses 2 bytes.
If you want to prevent larger values to be inserted,
you could use a check constraint.

How do you ensure that a one-byte range type only occupies one byte?

If you use a smallint, it will use two bytes.

Quote:

Is it because of the SQL standard, that PostgreSQL doesn't have a one-
byte type, too?

I didn't check, but I don't think so. That would be surprising.

Quote:

Generally, I get the feeling the mainstream DBMS' around (PostgreSQL,
MySQL, Oracle, ...) don't like byte-wise types. Could it have to do
with two-byte memory alignment issues?

Maybe, but I guess that there is no hige demand for it.

Yours,
Laurenz Albe

#6

On 7 Sep., 16:37, "Laurenz Albe" <inv... (AT) spam (DOT) to.invalid> wrote:

Quote:

Karsten Wutzke wrote:
I see PostgreSQL doesn't have a real one-byte integral type, like
TINYINT. What do you use instead?

That's right.
You could use "smallint" instead which only uses 2 bytes.
If you want to prevent larger values to be inserted,
you could use a check constraint.

How do you ensure that a one-byte range type only occupies one byte?

If you use a smallint, it will use two bytes.

Is it because of the SQL standard, that PostgreSQL doesn't have a one-
byte type, too?

I didn't check, but I don't think so. That would be surprising.

It really doesn't contain one...

Quote:

Generally, I get the feeling the mainstream DBMS' around (PostgreSQL,
MySQL, Oracle, ...) don't like byte-wise types. Could it have to do
with two-byte memory alignment issues?

Maybe, but I guess that there is no hige demand for it.

Yours,
Laurenz Albe

Hmmm strange. I thought it might be the ideal size to store booleans
as well.

Karsten

#7

On 7 Sep., 13:58, Thomas Kellerer <OTPXDAJCS... (AT) spammotel (DOT) com> wrote:

Quote:

Karsten Wutzke, 07.09.2009 13:06:

Generally, I get the feeling the mainstream DBMS' around (PostgreSQL,
MySQL, Oracle, ...) don't like byte-wise types. Could it have to do
with two-byte memory alignment issues?

What's the use for a single-byte datatype? Space consideration should not matter nowadays.

Yes that's a good point. I just wonder why the SQL standard has never
included a one-byte type back in the days when space consideration
still used to be an issue.

Karsten

#8

Karsten Wutzke, 07.09.2009 18:16:

Quote:

Hmmm strange. I thought it might be the ideal size to store booleans
as well.

That's what the boolean type is for

Thomas

#9

Karsten Wutzke wrote:

Quote:

Is it because of the SQL standard, that PostgreSQL doesn't have a one-
byte type, too?

I didn't check, but I don't think so. That would be surprising.

It really doesn't contain one...

Oh, what I meant is that I don't think that the SQL Standard
*forbids* it.

Yours,
Laurenz Albe

#10

On 8 Sep., 08:33, Thomas Kellerer <OTPXDAJCS... (AT) spammotel (DOT) com> wrote:

Quote:

Karsten Wutzke, 07.09.2009 18:16:

Hmmm strange. I thought it might be the ideal size to store booleans
as well.

That's what the boolean type is for

Thomas

Yes, I just meant internally. Since I don't have a PostgreSQL running
anywhere, could you find out for me how many bytes are occupied by a
BOOLEAN, please? (it would be rather strange for PostgreSQL to store
BOOLEANs as byte, but not to offer a one-byte integral type...)

Karsten