Re: copy table from file: with row replacement?

Michael Enke wrote:
> Hello all,
> I have a feature request as I think it is not possible with the actual version:
> 
> I want to load huge amount of data and I know that COPY is much faster than doing inserts.
> But in my case I have an already filled table and rows (not all, only partly) from this table
> should be replaced. The table has a primary key for one column.
> If I do a COPY table FROM file and the key value already exists, postgresql tells me
> that the import is not possible because of the violation of the PK.
> 
> If postgres is aware of such a violation, couldn't there be an option to the COPY command
> to delete such existing rows so that a COPY table FROM file will never generate a PK violation message
> but replaces existing rows?
> 
> If this is not possible, would it be the next fastes solution to create a before trigger and to
> delete rows in this trigger? Or is this not different from issuing for every line an insert
> and if this fails (because of the PK) than an update?

I would just COPY into another table, remove any duplicates by joining
the two tables, and then do a INSERT INTO ... SELECT.

--  Bruce Momjian   bruce@momjian.us EnterpriseDB    http://www.enterprisedb.com
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