From: Adrian Klaver <aklaver@comcast.net>
To: pgsql-general@postgresql.org
Subject: Re: FW: How to upload data to postgres
Date: Tue, 9 Sep 2008 19:43:13 -0700
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Cc: "Markova, Nina" <nmarkova@nrcan.gc.ca>
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On Tuesday 09 September 2008 1:54:12 pm Markova, Nina wrote:
> So far I tried;
>
> 1)  I have copied data from Ingres in ASCII (using Ingres copydb
> command).
> 2)  created a  table in a Postgres database
> 3)  tried loading data into Potgres table - encounter problems.
>
> For 1) (the Ingres part)
> =====================
> Ingres used the following copy commands:
>
> copy site(
>         sta= varchar(0)tab,
>         ondate= varchar(0)tab,
>         offdate= varchar(0)tab,
>         lat= c0tab,
>         lon= c0tab,
>         elev= c0tab,
>         regist_code= varchar(0)tab,
>         vault_cond= varchar(0)tab,
>         geology= varchar(0)tab,
>         comment= varchar(0)tab,
>         initials= varchar(0)tab,
>         lddate= c0nl,
>         nl= d0nl)
> into '/tmp/site.dba'
>
> Normally Ingres will use this command to copy data from a file:
> copy site(
>         sta= varchar(0)tab,
>         ondate= varchar(0)tab,
>         offdate= varchar(0)tab,
>         lat= c0tab,
>         lon= c0tab,
>         elev= c0tab,
>         regist_code= varchar(0)tab,
>         vault_cond= varchar(0)tab,
>         geology= varchar(0)tab,
>         comment= varchar(0)tab,
>         initials= varchar(0)tab,
>         lddate= c0nl,
>         nl= d0nl)
> from '/vm04-0/home/postgres/test/site.dba'
>
> For 3)
> =====
> - I got error when I tried to copy with Ingres-like copy command.
> - Then I tried to copy with simple 'copy site from
> '/vm04-0/home/postgres/test/site-c.dba' - ERROR:  value too long for
> type character varying(5)

The ERROR explains it. The value you are bringing over from the Ingres 
database is to long for a varchar(5) field.

Instead of rehashing the documentation I will point you to the relevant 
section that pertains to Postgres COPY:
http://www.postgresql.org/docs/8.3/interactive/sql-copy.html

>
> - I had no luck either when used binary copying - postgres complained
> about signature:
> copy site from  '/vm04-0/home/postgres/test/site.dba'   with binary
>
> ERROR:  COPY file signature not recognized
>
> ========================
> I have couple of questions as well.
> ========================
> Q1: is there an equivalent of copydb in postgres (in Ingres copydb
> creates copy statements for all database tables in a single file)

See pg_dump:
http://www.postgresql.org/docs/8.3/interactive/app-pgdump.html

> Q2:  how to say in postgres that a field has no default values (in
> Ingres 'not default' is used - and this produced an error in postgres
> CREATE TABLE command)

The CREATE TABLE only takes a DEFAULT clause. If you want no default don't 
specify anything:

 lat float not null,

Since you specified NOT NULL you will have to specify some value on INSERT.

>
> Create table site (
>         sta varchar(5) not null,
>         ondate varchar(8) not null,
>         offdate varchar(8) not null,
>         lat float not null not default, ----->
>         lon float not null not default
> )
>
> Q3:  How to specify storage structure of a table (again in Ingres
> 'modify' statement is used to specify btree, isam or hash structure). In
> the Postgres documentation I only saw  how to create an index with a
> specific structure.

As far as I know this cannot be done in Postgres. The only way you can modify 
the storage parameters is :

"Storage Parameters

The WITH clause can specify storage parameters for tables, and for indexes 
associated with a UNIQUE or PRIMARY KEY constraint. Storage parameters for 
indexes are documented in CREATE INDEX. The only storage parameter currently 
available for tables is:

FILLFACTOR

    The fillfactor for a table is a percentage between 10 and 100. 100 
(complete packing) is the default. When a smaller fillfactor is specified, 
INSERT operations pack table pages only to the indicated percentage; the 
remaining space on each page is reserved for updating rows on that page. This 
gives UPDATE a chance to place the updated copy of a row on the same page as 
the original, which is more efficient than placing it on a different page. 
For a table whose entries are never updated, complete packing is the best 
choice, but in heavily updated tables smaller fillfactors are appropriate. "

This only applies to later versions of Postgres. 

>
> In Ingres: modify site to isam unique on sta, ondate (means structure
> isam, primary key is on 2 fields - sta and ondate)
>
> Thanks in advance,
> Nina
>
> > ______________________________________________
> > From: 	Markova, Nina
> > Sent:	September 9, 2008 14:32
> > To:	pgsql-general@postgresql.org
> > Subject:	How to upload data to postgres
> >
> > Hi again,
> >
> > I need to load data from Ingres database to Postgres database.  What's
> > the easiest way?
> >
> > Thanks,
> > Nina


-- 
Adrian Klaver
aklaver@comcast.net