Re: Creating constraint dynamically

sivapostgres@yahoo.com schreef op ma 22-08-2022 om 07:29 [+0000]:

ALTER TABLE public.tx_barcode_stock 
ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK 
( (branchcode = '1'::bpchar  and barcodeitem = 'Y'::bpchar and
closingstock >= 0::numeric)  Or (branchcode = '1' and barcodeitem =
'N'::bpchar and closingstock >= 0::numeric )  Or (branchcode =
'2'::bpchar  and barcodeitem = 'Y'::bpchar and closingstock >=
0::numeric)  Or (branchcode = '2' and  barcodeitem = 'N'::bpchar and
closingstock >= 0::numeric ) ) NOT VALID; 

After creation, when we check what we find is  [ in PgAdmin ]
ALTER TABLE public.tx_barcode_stock
    ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK (branchcode::bpchar =
'1'::bpchar AND barcodeitem = 'Y'::bpchar AND closingstock >=
0::numeric OR branchcode::text = '1'::text AND barcodeitem =
'N'::bpchar AND closingstock >= 0::numeric OR branchcode::bpchar =
'2'::bpchar AND barcodeitem = 'Y'::bpchar AND closingstock >=
0::numeric OR branchcode::text = '2'::text AND barcodeitem =
'N'::bpchar AND closingstock >= 0::numeric)
    NOT VALID;

We have only one bracket, in the final updated one.

Since there are AND and OR conditions, without brackets the whole
conditions becomes useless. 

did you see
https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-PRECEDENCE
?

mvg,
Wim

On 8/22/22 13:09, Wim Bertels wrote:

sivapostgres@yahoo.com schreef op ma 22-08-2022 om 07:29 [+0000]:

ALTER TABLE public.tx_barcode_stock
ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK
( (branchcode = '1'::bpchar  and barcodeitem = 'Y'::bpchar and
closingstock >= 0::numeric)  Or (branchcode = '1' and barcodeitem =
'N'::bpchar and closingstock >= 0::numeric )  Or (branchcode =
'2'::bpchar  and barcodeitem = 'Y'::bpchar and closingstock >=
0::numeric)  Or (branchcode = '2' and  barcodeitem = 'N'::bpchar and
closingstock >= 0::numeric ) ) NOT VALID;

After creation, when we check what we find is  [ in PgAdmin ]
ALTER TABLE public.tx_barcode_stock
    ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK (branchcode::bpchar =
'1'::bpchar AND barcodeitem = 'Y'::bpchar AND closingstock >=
0::numeric OR branchcode::text = '1'::text AND barcodeitem =
'N'::bpchar AND closingstock >= 0::numeric OR branchcode::bpchar =
'2'::bpchar AND barcodeitem = 'Y'::bpchar AND closingstock >=
0::numeric OR branchcode::text = '2'::text AND barcodeitem =
'N'::bpchar AND closingstock >= 0::numeric)
    NOT VALID;

We have only one bracket, in the final updated one.

Since there are AND and OR conditions, without brackets the whole
conditions becomes useless.

did you see
https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-PRECEDENCE
?

mvg,
Wim

You can use plpgsql function
alter table tale_name add constraint xyz  check (func(table_name))

On Mon, 22 Aug 2022 at 09:29, sivapostgres@yahoo.com
<sivapostgres@yahoo.com> wrote:

We populate constraint string dynamically and add it to the table with alter table command. It gets added, but without the required brackets.

Brackets are NOT required in your example. You are doing a classic
form, OR of ANDs, sometime called sum of products. And has greater
precedence than OR ( amongst other things because this form of
conditions is used a lot ), as it has been pointed, so brackets (
round brackets are usually called parentheses abbreviated to parens,
in programming brackets is normaly nor used for those ) are not
necessary. What the system is doing is parsing and normalizing your
condition ( note how it changes bpchar to text and add types in some
places ) and reconstructing the condition, without brackets because
they are not required.

Since there are AND and OR conditions, without brackets the whole conditions becomes useless.

Before stating these things, test, try to insert a condition violating
row to see if the condition is really useless, it is very rare to find
a bug ( changing the semantics of the condition would be one ) like
these.

How to create a constraint like the above one, with braces in tact ? Or any other way that we can implement a check constraint as above?

The condition IS correctly implemented, but nothing guarantees you the
text returned by pgadmin will be the exact same condition you sent. In
fact, AFAIK, nothing guarantees you can recover a condition set on a
column. It is transformed to an equivalent. I'm not sure how it is
exactly done, but it probably also does whitespace normalization and
constant folding.

Francisco Olarte.

On Mon, Aug 22, 2022 at 12:59 PM sivapostgres@yahoo.com <
sivapostgres@yahoo.com> wrote:

Hello,
Using PG 11.4

We populate constraint string dynamically and add it to the table with
alter table command. It gets added, but without the required brackets.
What we build is
ALTER TABLE public.tx_barcode_stock
ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK
( (branchcode = '1'::bpchar and barcodeitem = 'Y'::bpchar and
closingstock >= 0::numeric) Or (branchcode = '1' and barcodeitem =
'N'::bpchar and closingstock >= 0::numeric ) Or (branchcode = '2'::bpchar
and barcodeitem = 'Y'::bpchar and closingstock >= 0::numeric) Or
(branchcode = '2' and barcodeitem = 'N'::bpchar and closingstock >=
0::numeric ) ) NOT VALID;

After creation, when we check what we find is [ in PgAdmin ]
ALTER TABLE public.tx_barcode_stock
ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK (branchcode::bpchar =
'1'::bpchar AND barcodeitem = 'Y'::bpchar AND closingstock >= 0::numeric OR
branchcode::text = '1'::text AND barcodeitem = 'N'::bpchar AND closingstock

= 0::numeric OR branchcode::bpchar = '2'::bpchar AND barcodeitem =

'Y'::bpchar AND closingstock >= 0::numeric OR branchcode::text = '2'::text
AND barcodeitem = 'N'::bpchar AND closingstock >= 0::numeric)
NOT VALID;

We have only one bracket, in the final updated one.

Since there are AND and OR conditions, without brackets the whole
conditions becomes useless.

How to create a constraint like the above one, with braces in tact ? Or
any other way that we can implement a check constraint as above?

Happiness Always
BKR Sivaprakash

I guess it's because pgadmin uses pg_get_constraintdef ( *constraint* oid [,
*pretty* boolean ] ) pretty is true.
if you use pg_get_constraintdef ( *constraint* oid *,false* ) you will see
more braces.

--
I recommend David Deutsch's <<The Beginning of Infinity>>

Jian

Hello,
Sorry for delay... I had to go on leave..
Checked, it's our mistake here.   The issue is not what I described, but in the replicated database where the constraint was not updated.  Correcting the constraint there solved this issue.  
Sorry for not checking properly before coming here.
Happiness Always
BKR Sivaprakash

On Monday, 22 August, 2022 at 03:54:30 pm IST, jian he <jian.universality@gmail.com> wrote:

On Mon, Aug 22, 2022 at 12:59 PM sivapostgres@yahoo.com <sivapostgres@yahoo.com> wrote:

Hello,Using PG 11.4
We populate constraint string dynamically and add it to the table with alter table command.  It gets added, but without the required brackets.  What we build isALTER TABLE public.tx_barcode_stock ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK ( (branchcode = '1'::bpchar  and barcodeitem = 'Y'::bpchar and closingstock >= 0::numeric)  Or (branchcode = '1' and barcodeitem = 'N'::bpchar and closingstock >= 0::numeric )  Or (branchcode = '2'::bpchar  and barcodeitem = 'Y'::bpchar and closingstock >= 0::numeric)  Or (branchcode = '2' and  barcodeitem = 'N'::bpchar and closingstock >= 0::numeric ) ) NOT VALID; 
After creation, when we check what we find is  [ in PgAdmin ]ALTER TABLE public.tx_barcode_stock    ADD CONSTRAINT "tx_barcode_stock_CK1" CHECK (branchcode::bpchar = '1'::bpchar AND barcodeitem = 'Y'::bpchar AND closingstock >= 0::numeric OR branchcode::text = '1'::text AND barcodeitem = 'N'::bpchar AND closingstock >= 0::numeric OR branchcode::bpchar = '2'::bpchar AND barcodeitem = 'Y'::bpchar AND closingstock >= 0::numeric OR branchcode::text = '2'::text AND barcodeitem = 'N'::bpchar AND closingstock >= 0::numeric)    NOT VALID;
We have only one bracket, in the final updated one.
Since there are AND and OR conditions, without brackets the whole conditions becomes useless.  
How to create a constraint like the above one, with braces in tact ?   Or any other way that we can implement a check constraint as above?
Happiness Always
BKR Sivaprakash

I guess it's because  pgadmin uses pg_get_constraintdef ( constraint oid [, pretty boolean ] ) pretty is true.if you use pg_get_constraintdef ( constraint oid ,false )  you will see more braces.

--
 I recommend David Deutsch's <<The Beginning of Infinity>>

  Jian