Re: [sqlalchemy] How to declare ORM class with index that in postgress is created with GREATEST
On 13Mar2023 09:05, Yoav Kopfstein wrote: I would like to declare an index in orm class with sqlalchemy 1.4 The index is created in postgres with this command: create index index_name on table_name (GREATEST(field_1, field_2)); how can I do it? (with __table_args__ or without ) Do you have the rest of your table definiton to hand for comparison? Have you see this example in the core docs: https://docs.sqlalchemy.org/en/14/core/constraints.html#indexes Cheers, Cameron Simpson -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/ZA%2BGtuidHpusT%2BRD%40cskk.homeip.net.
Re: [sqlalchemy] Re: Translating sql query to sqlalchemy
On 18Aug2019 19:36, Ira Fuchs wrote: Thanks for your reply and offer to help. I am able to create an Engine and connect to the MySQL db. I can execute simple sql queries although I wasn't able to get the query I posted to work due to a syntax error (probably having to do with the quotes). I have not mapped any tables to classes. Perhaps you could post your current query code and the error message. Cheers, Cameron Simpson -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/20190819044719.GA24610%40cskk.homeip.net.
Re: [sqlalchemy] How to update jsonb blob subset values using sqlalchemy orm ?
On 04Jul2019 10:12, Mike Bayer wrote:
it looks like Postgresql 9.5+ has a new function jsonb_set that does this, this
can be used with func. If you aren't on pg9.5 you might have to update the
whole value.
full POC below
[... nice code which works with modern PostgreSQL ...]
And if you don't have direct SQL support and instead need to modify the
JSON blob yourself ...
I should point out first that SQLAlchemy has an "index value as tuple"
mode which can dig into JSON columns along the lines of:
row.the_json_column_name[('a','b','field1')]
Or alternatively you could consider my cs.sqlalchemy_utils PyPI package,
which has a small facility for this:
An @json_column decorator function and some associated get_json_field()
and set_json_field() functions for working against JSON blobs.
The functions take a JSON blob and a notional field_name like "a.b.c"
where that would reference:
{"a": {"b": {"c": 9, "d": 10}}}
The @json_column decorator decorates a declariative class with a
ficitious column associated with a "field" within an existing JSON
column. Eg:
@json_column("field1", "a.b.field1", "the_json_column_name")
class SomethingRow(Base):
...
the_json_column_name = Column(JSON, comment='JSON encoded addtional data')
...
where Base is your ORM declarative base class and SomethingRow is your
table row class. This makes a ".field1" property on each instance which
fetches from the json column or modifies the json column when assigned.
It doesn't make any SQL support - it just modifies the session entity
and you let the ORM update the database on transaction commit etc.
So that you can go:
# fetch and print the value from inside row.the_json_column_name
print(row.field1)
# modify row.the_json_column_name["a"]["b"]["field1"]
row.field1 = 12
It isn't heavily tested yet, but it's been working for me.
Cheers,
Cameron Simpson
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
---
You received this message because you are subscribed to the Google Groups "sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sqlalchemy/20190705003416.GA9490%40cskk.homeip.net.
For more options, visit https://groups.google.com/d/optout.
Re: [sqlalchemy] Re: Documentation options
On 29Mar2019 05:33, Rich Shepard wrote:
On Fri, 29 Mar 2019, Xavier Bustamante Talavera wrote:
I use Dash <https://kapeli.com/dash> to read SQLAlchemy documentation,
which is great to search through it and works offline (it downloads the
whole docs).
This looks like the ideal solution. I'll install Dash and use it.
If it is of use I have this shell function:
open_dash () {
open "dash://$*"
}
and this alias:
alias //=open_dash
so that I can go "// search terms here" from the shell command line.
Avoids some painful touchpad/mouse mucking around.
Cheers,
Cameron Simpson
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
---
You received this message because you are subscribed to the Google Groups "sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.
