Re: patch: xmltable - proof concept - Mailing list pgsql-hackers
From | Pavel Stehule |
---|---|
Subject | Re: patch: xmltable - proof concept |
Date | |
Msg-id | CAFj8pRAfE8iPzhR+WtOxCYfEJ8YPRuqqAiP-HoQLLfUdZYLAwQ@mail.gmail.com Whole thread Raw |
In response to | patch: xmltable - proof concept (Pavel Stehule <pavel.stehule@gmail.com>) |
List | pgsql-hackers |
Hi
2016-08-07 11:15 GMT+02:00 Pavel Stehule <pavel.stehule@gmail.com>:
RegardsExample:The full ANSI/SQL, or Oracle compatible implementation is not possible due limits of libxml2, but for typical usage it should to work well. It doesn't need any new reserved keyword, so there should not be hard barriers for accepting (when this work will be complete).I invite any help with documentation and testing.The code is not clean now, but it does almost of expected work. The usage is simple. It is fast - 16K entries in 400ms.HiI am sending a initial implementation of xmltable function:
postgres=# SELECT * FROM xmldata;
┌─────────────────────────────────────────────────────────── ───────┐
│data │
╞═══════════════════════════════════════════════════════════ ═══════╡
│ <ROWS>↵│
│ <ROW id="1">↵│
│ <COUNTRY_ID>AU</COUNTRY_ID>↵│
│ <COUNTRY_NAME>Australia</COUNTRY_NAME> ↵│
│ <REGION_ID>3</REGION_ID>↵│
│ </ROW>↵│
│ <ROW id="2">↵│
│ <COUNTRY_ID>CN</COUNTRY_ID>↵│
│ <COUNTRY_NAME>China</COUNTRY_NAME> ↵│
│ <REGION_ID>3</REGION_ID>↵│
│ </ROW>↵│
│ <ROW id="3">↵│
│ <COUNTRY_ID>HK</COUNTRY_ID>↵│
│ <COUNTRY_NAME>HongKong</COUNTRY_NAME> ↵│
│ <REGION_ID>3</REGION_ID>↵│
│ </ROW>↵│
│ <ROW id="4">↵│
│ <COUNTRY_ID>IN</COUNTRY_ID>↵│
│ <COUNTRY_NAME>India</COUNTRY_NAME> ↵│
│ <REGION_ID>3</REGION_ID>↵│
│ </ROW>↵│
│ <ROW id="5">↵│
│ <COUNTRY_ID>JP</COUNTRY_ID>↵│
│ <COUNTRY_NAME>Japan</COUNTRY_NAME> ↵│
│ <REGION_ID>3</REGION_ID><PREMIER_NAME>Sinzo Abe</PREMIER_NAME>↵│
│ </ROW>↵│
│ <ROW id="6">↵│
│ <COUNTRY_ID>SG</COUNTRY_ID>↵│
│ <COUNTRY_NAME>Singapore</COUNTRY_NAME> ↵│
│ <REGION_ID>3</REGION_ID><SIZE unit="km">791</SIZE>↵│
│ </ROW>↵│
│ </ROWS>│
└─────────────────────────────────────────────────────────── ───────┘
(1 row)
postgres=# SELECT xmltable.*
postgres-# FROM (SELECT data FROM xmldata) x,
postgres-# LATERAL xmltable('/ROWS/ROW'
postgres(#PASSING data
postgres(#COLUMNS id int PATH '@id',
postgres(#country_name text PATH 'COUNTRY_NAME',
postgres(#country_id text PATH 'COUNTRY_ID',
postgres(#region_id int PATH 'REGION_ID',
postgres(#size float PATH 'SIZE',
postgres(#unit text PATH 'SIZE/@unit',
postgres(#premier_name text PATH 'PREMIER_NAME' DEFAULT 'not specified');
┌────┬──────────────┬────────────┬───────────┬──────┬──────┬ ───────────────┐
│ id │ country_name │ country_id │ region_id │ size │ unit │ premier_name │
╞════╪══════════════╪════════════╪═══════════╪══════╪══════╪ ═══════════════╡
│ 1 │ Australia │ AU │ 3 │ ¤ │ ¤ │ not specified │
│ 2 │ China │ CN │ 3 │ ¤ │ ¤ │ not specified │
│ 3 │ HongKong │ HK │ 3 │ ¤ │ ¤ │ not specified │
│ 4 │ India │ IN │ 3 │ ¤ │ ¤ │ not specified │
│ 5 │ Japan │ JP │ 3 │ ¤ │ ¤ │ Sinzo Abe │
│ 6 │ Singapore │ SG │ 3 │ 791 │ km │ not specified │
└────┴──────────────┴────────────┴───────────┴──────┴──────┴ ───────────────┘
(6 rows)
I am sending updated version - the code is not better, but there is full functionality implemented.
* xmlnamespaces,
* default xmlnamespace,
* default xmlnamespace,
* ordinality column,
* NOT NULL constraint,
* mode without explicitly defined columns.
Lot of bugs was fixed - it is ready for some playing.
tests, comments, notes, comparing with other db are welcome. Some behave is based by libxml2 possibilities - so only XPath is supported.
Regards
Pavel
Pavel
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