Re: How to avoid trailing zero (after decimal point) for numeric type column - Mailing list pgsql-bugs

2018-03-01 7:45 GMT+01:00 Praveen Kumar <praveenkumar52028@gmail.com>:

Hey Pavel,

I am okay with the size

You can implement own numeric type, that will try to remove trailing zeros by default.  - Can I override the existing numeric type, or do you want me to create a custom numeric type?

you can hack Postgres and change, behave of numeric. But then there are issues with necessity of build own packages, ... so preferred way is use own numeric type like numeric2.

any data type in PostgreSQL is defined by some sets of functions - for you, you need to modify numeric_in function - just truncate zero from right and call numeric_in. You can look postgresql source code postgresql/contrib/citext - citext is based on text type

It is not lot of work. But it is not easy work, for people who don't know C language and PostgreSQL ecosystem.

or clean inserted values on app side. -  Does this means, Change my application code? 

yes. It is most easy and probably correct solution for you. Postgres is not Oracle, and Oracle is not Postgres, and some differences are best solved on application level.

Regards

Pavel

 

Thanks,

Praveen

On Wed, Feb 28, 2018 at 7:58 PM, Pavel Stehule <pavel.stehule@gmail.com> wrote:

2018-02-28 15:23 GMT+01:00 Praveen Kumar <praveenkumar52028@gmail.com>:

maybe "double precision" is better for you.  -   Yes Pavel,I thought of using doible precion,but as per the documentation

double precision

8 bytes

variable-precision, inexact

15 decimal digits precision

It can accept only 15 digits, but my tables may have more than that.

That is why looking for an alternative.

You can implement own numeric type, that will try remove trailing zeros by default. It is few days work - or clean inserted values on app side.

trailing zeros has not impact on value size - so there should not be any issue, if you store it

 ides_jmmaj_prac=# select pg_column_size('1.0'::numeric);
┌────────────────┐
│ pg_column_size │
╞════════════════╡
│              8 │
└────────────────┘
(1 row)

Time: 0,481 ms
ides_jmmaj_prac=# select pg_column_size('1.0000000000000000000000000000000000000000000000000000000000000'::numeric);
┌────────────────┐
│ pg_column_size │
╞════════════════╡
│              8 │
└────────────────┘
(1 row)

Regards

Pavel

Thanks,

Praveen

On Wed, Feb 28, 2018 at 7:42 PM, Pavel Stehule <pavel.stehule@gmail.com> wrote:

2018-02-28 15:09 GMT+01:00 Praveen Kumar <praveenkumar52028@gmail.com>:

Hi Pavel,

Selection is not the problem,

Insertion is the problem when we insert data with below query

set lc_numeric to 'C';

INSERT INTO BLOB_TEST_TABLE(ID)VALUES (2500.0);

And,

If I do the select after the above insert,

select * from public.blob_test_table where id = 2500;

id
numeric
-------------
2500.0

------------------------------------------------------------------- THIS IS NOT EXPECTED

But, I want it to be shown as below where 2500 without precision 0

It should show

id
numeric
-------------
2500

-------------------------------------------------------------------- EXPECTED OUTPUT

then you have to do same cleaning on INSERT - or you different data type - maybe "double precision" is better for you.

There is not strong equality between oracle's number and postgres's numeric.

Regards

Pavel

Please, don't do top post https://en.wikipedia.org/wiki/Posting_style#Top-posting

 

Thanks,

Praveen

On Wed, Feb 28, 2018 at 7:06 PM, Pavel Stehule <pavel.stehule@gmail.com> wrote:

Hi

2018-02-28 13:34 GMT+01:00 pkashimalla <praveenkumar52028@gmail.com>:

Hello Team,

We have recently migrated our database from Oracle
And there are few of my tables with numeric column type.

In below example
I did insertion from java program with below code snippet

Double object = 10.0;
String inserRecordQuery_NEWWAY11 = "INSERT INTO BLOB_TEST_TABLE(id)VALUES
(?)";
selectPrepareStmt.setObject(1, object,Types.NUMERIC);
int count = selectPrepareStmt.executeUpdate();

it inserted like this.

select id from blob_test_table;

id
numeric
-------------
10.0


In this case, when a decimal point is equal to 0 then,  I don't want to see
the precision and the value in the column should just 10

And If I execute code,

Double object = 10.5801
String inserRecordQuery_NEWWAY11 = "INSERT INTO BLOB_TEST_TABLE(id)VALUES
(?)";
selectPrepareStmt.setObject(1, object,Types.NUMERIC);
int count = selectPrepareStmt.executeUpdate();

Now ,the value in the column should be 10.5801 as the precision is greater
than ZERO

Because of this, the migrated data (from Oracle) is without PRECISION ZERO
and the new data which is being inserted is with PRECISION ZERO.


select id from blob_test_table;

id
numeric
-------------
10.0
10
11
11.0


Is there a possible setting in PostgreSQL server to achieve this?

FYI -

Oracle's NUMBER column type is handling it as I expected.
I migrate Oracle's NUMBER column as just NUMERIC column in PostgreSQL

you can try to use a "to_char" function from orafce extension https://github.com/orafce/orafce

ides_jmmaj_prac=# set lc_numeric to 'C';
SET
Time: 0,219 ms
ides_jmmaj_prac=# select to_char(123.22000);
┌─────────┐
│ to_char │
╞═════════╡
│ 123.22  │
└─────────┘
(1 row)

Or PostgreSQL function

ides_jmmaj_prac=# select to_char(123.22000, 'FM99999.9999');
┌─────────┐
│ to_char │
╞═════════╡
│ 123.22  │
└─────────┘
(1 row)

Regards

Pavel

 

Thanks,
Praveen



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