Hello,
Yesterday I asked this question on IRC and the community kindly
answered. I was also asked to send an email to the mailing list
explaining my use case. Thus this email.
So, in the scope of my current project at work I need to see if Neo4J would
be a valid alternative to PostgreSQL to store our data. Were hoping to
have better flexibility and better performance on some requests.
In order to document the steps of my exploration I decided to use
org-mode which I discovered a couple of weeks ago (I use it mainly to
keep a diary of my work days).
The first step in my investigation is to migrate the data from Postgres
to Neo4j via CSV files. Since our schema contains quite a bit of tables
and relations I decided to generate corresponding SQL COPY ... TO ...
requests by first putting variable data in a array, second generating
requests with a python source bloc and then feed it to a SQL bloc. Here
is the result:
#+tblname: rels-data
| computer | id | house | house_id | EQUIPS |
computer |
| house | id | block | block_id | IN |
house |
| block | id | city | city_id | IN | block |
| city | id | country | country_id | IN | city |
| city | id | city_group | city_group_id | BELONGS_TO |
city |
#+name: import-rels
#+begin_src python :var rels=rels-data :results value verbatim
res = ["""COPY (
SELECT '{0}' || {1} as ":START_ID", '{2}' || {3} as ":END_ID", '{4}'
as ":TYPE"
FROM "{5}"
) TO '/data/rels_{0}_{2}.csv' WITH CSV HEADER;""".format(*row) for row
in rels]
return "\n".join(res)
#+end_src
#+name: export-data
#+header: :engine postgresql
#+header: :dbhost localhost
#+header: :dbuser mrwho
#+header: :database whatever
#+header: :noweb no-export
#+begin_src sql
<<import-rels()>>
#+end_src
All the magic is in the use of noweb[1] feature.
If you have any questions or remarks don't hesitate.
Regards,
[1] https://orgmode.org/manual/noweb.html
