I've a backup table with several distinct IDS… I wanna do a BACKUP of those rows, by ID.
-
The function has to be executed by a limit of account_id ( select dump(21); – Where 21 = number of account_id to be touched by the function )
-
Each account_id must have a different file name. Examples below:
Example:
COPY
(
SELECT * FROM backup_table WHERE id = 1112 AND status = 1
)
TO '/var/lib/pgsql/1112.sql';
COPY
(
SELECT * FROM backup_table WHERE id = 1113 AND status = 1
)
TO '/var/lib/pgsql/1113.sql';
COPY
(
SELECT * FROM backup_table WHERE id = 1114 AND status = 1
)
TO '/var/lib/pgsql/1114.sql';
Question:
Can I create maybe a function to do that automatically? There are thousands of those IDS and would take ages by doing manually.
UPDATE 1:
Tried to do:
CREATE or REPLACE FUNCTION dump(integer)
RETURNS integer AS $$
declare
crtRow record;
begin
FOR crtRow in execute 'select account_id from backup_table WHERE migrated = 1 AND account_id = '|| $1
LOOP
COPY
(SELECT * FROM backup_table WHERE migrated = 1 AND account_id = crtRow.account_id)
TO '/var/lib/pgsql/backup/%s.sql';
end loop;
return integer;
end
$$ language 'plpgsql';
- Each account_Id would have a file with its ID
- When calling the function, I want to specify the numbers of account_Ids I wanna do the dump
However it isn't working…
UPDATE 2:
CREATE or REPLACE FUNCTION function_1(rows integer)
RETURNS void AS $$
declare
crtRow record;
begin
FOR crtRow in EXECUTE 'select DISTINCT(account_id) from backup_table WHERE migrated = 1 AND account_id IN '|| $1
LOOP
COPY
(SELECT * FROM backup_table WHERE migrated = 1 AND account_id = crtRow.account_id)
TO '/var/lib/pgsql/' || crtrow.account_id || '.csv';
end loop;
end
$$ language 'plpgsql';
Error:
ERROR: syntax error at or near "||" LINE 12: TO '/var/lib/pgsql/'
|| crtrow.account_id |…
UPDATE 3: amacvar's answer
CREATE or REPLACE FUNCTION function_1(rows integer)
RETURNS void AS $$
begin
execute 'COPY
(
SELECT * FROM backup_table WHERE id = ' || rows || 'AND status = 1
)
TO ''/var/lib/pgsql/'||rows||'.sql''';
end
$$ language 'plpgsql';
The above function based on the amacvar's answer works. The problem is that I have to specify the id number…
Example:
`select function_1(25)` - Where 25 = id
That isn't good for me, as I have thousands of ids and can't specify them manually.
What I need is:
The same function above, but with a LIMIT of IDS to be specified when
the function is called:
EXAMPLE:
select function_1(100)
– WHERE 100 = numbers of id to be copied
- How can I do that?
Best Answer
The scripting answers above will obviously work.
But, assuming you have to, have to, have it executed from within the DB (let us know why :) ), the code below (minus the loop, etc.) should get you on your way.
You were very close btw.
EDIT 1: function loop example and formatting
Executed as
Please note there are no checks being performed here.
E.g. This will create a zero byte 3.dat even if there is no id=3 in the table
EDIT 2: A more extensible option for thousands of id would be