Insert multiple records from xml - postgresql

Question

I want bulk insert into a PostgreSQL database: backend code would create XML like
<items>
<i dt="2014-08-01" name="vvv" count="12" />
<i dt="2014-08-02" name="zzz" count="6" />
</items>
which I want to pass to a function and save all the values in one go.
But I'm stuck at xpath: each "column" seems to be an array of values, and I'm not sure how to insert them into a table then. Here's a test example:
CREATE TEMP TABLE temp_values (dt date, name varchar, count int);
WITH x AS (SELECT '
<items>
<i dt="2014-08-01" name="vvv" count="12" />
<i dt="2014-08-02" name="zzz" count="6" />
<i dt="2014-08-03" name="bbd" count="10" />
</items>'::xml AS t
)
INSERT INTO temp_values
SELECT
xpath('/items/i/#dt', t),
xpath('/items/i/#name', t),
xpath('/items/i/#count', t)
FROM x;
Now, in the end I want temp_values to have 3 records, as in the XML, but the table is empty.
If you comment out the "insert into" line, you'd see that the values are parsed correctly. It's just that it returns a single record where each column is an array, instead of returning multiple records.
What am I missing?

Answer 1

Ok, apparently unnest and array indexing is the solution:
unnest(array) | expand an array to a set of rows
So the code would be
CREATE TEMP TABLE temp_values (dt date, name varchar, count int) ON COMMIT DROP;
WITH x AS (SELECT '
<items>
<i dt="2014-08-01" name="vvv" count="12" />
<i dt="2014-08-02" name="zzz" count="6" />
<i dt="2014-08-03" name="bbd" count="10" />
</items>'::xml AS t
)
INSERT INTO temp_values
SELECT
CAST(CAST((xpath('//#dt', node))[1] as varchar) as date),
CAST((xpath('//#name', node))[1] as varchar),
CAST(CAST((xpath('//#count', node))[1] as varchar) as int)
FROM (SELECT unnest(xpath('/items/i', t)) AS node FROM x) sub;
SELECT * FROM temp_values

Answer 2

I'd prefer to delete some extra slashes before #:
CREATE TEMP TABLE temp_values (dt date, name varchar, count int) ON COMMIT DROP;
WITH x AS (SELECT '
<items>
<i dt="2014-08-01" name="vvv" count="12" />
<i dt="2014-08-02" name="zzz" count="6" />
<i dt="2014-08-03" name="bbd" count="10" />
</items>'::xml AS t
)
INSERT INTO temp_values
SELECT
CAST(CAST((xpath('#dt', node))[1] as varchar) as date),
CAST((xpath('#name', node))[1] as varchar),
CAST(CAST((xpath('#count', node))[1] as varchar) as int)
FROM (SELECT unnest(xpath('/items/i', t)) AS node FROM x) sub;
SELECT * FROM temp_values