Обсуждение: Mass Import/Generate PKs

I have a CSV file with 400,000 lines of email mailing list information that
I need to migrate to a new PostgreSQL database.

Each line has all the info I need except a PK (I usually use an int4 column
for a PK).

If the file were smaller I would probably just use Excel to pop in a PK and
then just load into the table...

Since Excel chokes on files greater than 65k lines, this won't work.

Is there a way to get this done inside psql for instance? Or another route?

Thanks,
Hunter

Hunter Hillegas wrote:
> I have a CSV file with 400,000 lines of email mailing list
> information that I need to migrate to a new PostgreSQL database.
>
> Each line has all the info I need except a PK (I usually use an int4
> column for a PK).

You could import the file into PostgreSQL and add a primary key column
later.

--
Peter Eisentraut
http://developer.postgresql.org/~petere/

That sounds nice and easy...

So, I would do something like 'ALTER TABLE' to generate the PK column? What
would be the best way to populate it? Is there an area of doco I should be
looking at?

Thanks,
Hunter


> From: Peter Eisentraut <peter_e@gmx.net>
> Date: Sat, 6 Nov 2004 21:21:25 +0100
> To: Hunter Hillegas <lists@lastonepicked.com>, PostgreSQL
> <pgsql-general@postgresql.org>
> Subject: Re: [GENERAL] Mass Import/Generate PKs
>
> Hunter Hillegas wrote:
>> I have a CSV file with 400,000 lines of email mailing list
>> information that I need to migrate to a new PostgreSQL database.
>>
>> Each line has all the info I need except a PK (I usually use an int4
>> column for a PK).
>
> You could import the file into PostgreSQL and add a primary key column
> later.
>
> --
> Peter Eisentraut
> http://developer.postgresql.org/~petere/
>

the simplest way to do it seems to be adding a SERIAL column to your table, and then adding a primary key constraint:

1)insert data into table
2)ALTER TABLE <table> ADD id SERIAL;
3)ALTER TABLE <table> ADD CONSTRAINT <table>_pk PRIMARY KEY (id);

you can check the docs for the SERIAL type: http://www.postgresql.org/docs/7.4/static/datatype.html#DATATYPE-SERIAL

On Sat, 2004-11-06 at 17:29, Hunter Hillegas wrote:

That sounds nice and easy...

So, I would do something like 'ALTER TABLE' to generate the PK column? What
would be the best way to populate it? Is there an area of doco I should be
looking at?

Thanks,
Hunter


> From: Peter Eisentraut <peter_e@gmx.net>
> Date: Sat, 6 Nov 2004 21:21:25 +0100
> To: Hunter Hillegas <lists@lastonepicked.com>, PostgreSQL
> <pgsql-general@postgresql.org>
> Subject: Re: [GENERAL] Mass Import/Generate PKs
> 
> Hunter Hillegas wrote:
>> I have a CSV file with 400,000 lines of email mailing list
>> information that I need to migrate to a new PostgreSQL database.
>> 
>> Each line has all the info I need except a PK (I usually use an int4
>> column for a PK).
> 
> You could import the file into PostgreSQL and add a primary key column
> later.
> 
> -- 
> Peter Eisentraut
> http://developer.postgresql.org/~petere/
> 



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On Saturday November 6 2004 2:13, Franco Bruno Borghesi wrote:
> the simplest way to do it seems to be adding a SERIAL column to your
> table, and then adding a primary key constraint:
>
> 1)insert data into table
> 2)ALTER TABLE <table> ADD id SERIAL;
> 3)ALTER TABLE <table> ADD CONSTRAINT <table>_pk PRIMARY KEY (id);

You may also need to populate the id column with unique values in between
these two steps with something like "

    update table set id = nextval('table_id_seq'::text) where id isnull"

I don't think SERIAL does that for you.

Ed

I've tested it, and the SERIAL type populates the column when you add it

On Sat, 2004-11-06 at 18:56, Ed L. wrote:

On Saturday November 6 2004 2:13, Franco Bruno Borghesi wrote:
> the simplest way to do it seems to be adding a SERIAL column to your
> table, and then adding a primary key constraint:
>
> 1)insert data into table
> 2)ALTER TABLE <table> ADD id SERIAL;
> 3)ALTER TABLE <table> ADD CONSTRAINT <table>_pk PRIMARY KEY (id);

You may also need to populate the id column with unique values in between 
these two steps with something like "
	update table set id = nextval('table_id_seq'::text) where id isnull"

I don't think SERIAL does that for you.

Ed

Yes you can use the copy command. Check for


copy TABLE NAME from 'c:\\bcpdata\\Files\\FILENAME.txt' with delimiter
as '\t'  NULL as '';

When creating a table, use an incremental column (data type is serial).
Hope the above helps.

- Goutam


> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org] On Behalf Of
> Hunter Hillegas
> Sent: Saturday, November 06, 2004 3:01 PM
> To: PostgreSQL
> Subject: [GENERAL] Mass Import/Generate PKs
>
>
> I have a CSV file with 400,000 lines of email mailing list
> information that I need to migrate to a new PostgreSQL database.
>
> Each line has all the info I need except a PK (I usually use
> an int4 column for a PK).
>
> If the file were smaller I would probably just use Excel to
> pop in a PK and then just load into the table...
>
> Since Excel chokes on files greater than 65k lines, this won't work.
>
> Is there a way to get this done inside psql for instance? Or
> another route?
>
> Thanks,
> Hunter
>
>
>
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