Обсуждение: update table from csv file

I have been using COPY FROM to do a mass import of records from CSV files into a new database. I have discover however,
asmall number of records ( a few thousand) in one of the files that contain new data that needs to be added to the
database,but on rows that have a primary key and have already been inserted (so I can't use COPY FROM because it
violatesthe primary key).  

If the structure of the table is

id    data1    data2    data3

and the structure of the CSV file is

id    data1    data2    data3

and I need to update all the rows in data3 where the id = id.

I have created a temporary table and used COPY FROM to load the update data into the temporary table. I seem to be
stuckhowever. I thought I should be able to use the UPDATE command to update all columns and all rows the table.id =
tmp_table.id

Something like:

UPDATE table FROM tmp_table WHERE table.id = tmp_table.id;

Or am I completely off course?

On 12/28/2012 12:31 AM, Kirk Wythers wrote:
> I have been using COPY FROM to do a mass import of records from CSV files into a new database. I have discover
however,a small number of records ( a few thousand) in one of the files that contain new data that needs to be added to
thedatabase, but on rows that have a primary key and have already been inserted (so I can't use COPY FROM because it
violatesthe primary key).  
The standard solution is:

- COPY to a temporary table; then
- Use UPDATE ... FROM to merge the data from the temp table into the
main table, usually after locking the main table
> I have created a temporary table and used COPY FROM to load the update data into the temporary table. I seem to be
stuckhowever. I thought I should be able to use the UPDATE command to update all columns and all rows the table.id =
tmp_table.id
>
> Something like:
>
> UPDATE table FROM tmp_table WHERE table.id = tmp_table.id;
That's the usual solution, yes.

--
 Craig Ringer                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services