Обсуждение: character datatype explaination sought
I am testing Idempiere and have run across this in an example:
character(1) DEFAULT 'Y'::bpchar NOT NULL,
How does this differ from
character(1) DEFAULT 'Y' NOT NULL,
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"James B. Byrne" <byrnejb@harte-lyne.ca> writes:
> I am testing Idempiere and have run across this in an example:
> character(1) DEFAULT 'Y'::bpchar NOT NULL,
> How does this differ from
> character(1) DEFAULT 'Y' NOT NULL,
It doesn't. The former is just written with an explicit cast,
which the latter lacks, but the end result will be the same
because the parser will coerce the DEFAULT expression to the
column's type anyway.
(It helps to know that for reasons lost in the depths of time,
Postgres' internal name for the char(N) type is "bpchar".)
regards, tom lane
On Thu, 2020-10-15 at 10:07 -0400, James B. Byrne wrote: > I am testing Idempiere and have run across this in an example: > > character(1) DEFAULT 'Y'::bpchar NOT NULL, > > How does this differ from > > character(1) DEFAULT 'Y' NOT NULL, It is the same, only in the first version the type cast is explicit. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
On 10/15/20 7:07 AM, James B. Byrne wrote: > I am testing Idempiere and have run across this in an example: > > character(1) DEFAULT 'Y'::bpchar NOT NULL, > > How does this differ from > > character(1) DEFAULT 'Y' NOT NULL, It doesn't. From here: https://www.postgresql.org/docs/current/typeconv-query.html "... bpchar (“blank-padded char”, the internal name of the character data type) ..." > > > -- Adrian Klaver adrian.klaver@aklaver.com