Sequelize is used minimally, just to feed raw queries in transparently to any underlying database, and get minimally parsed results out for us, which we then assert with standard JavaScript. The queries themselves are all written by hand.
By default the examples run on SQLite. Just like the examples from sequelize example, you can set the database at runtime as:
./index.jsor./index.js l: SQLite./index.js p: PostgreSQL. You must manually create a database calledtmpand ensure that peer authentication works for it
Here we list only examples which we believe are standard SQL, and should therefore work across different SQL implementations:
- nodejs/sequelize/raw/index.js: basic hello world to demonstrate the setup and very simple functionality
- nodejs/sequelize/raw/many_to_many.js: illustrates many-to-many relations with JOIN. Contains:
- SQL transaction examples:
- nodejs/sequelize/raw/commit_error.js: stackoverflow.com/questions/27245101/why-should-we-use-rollback-in-sql-explicitly/27245234#27245234 and stackoverflow.com/questions/48277519/how-to-use-commit-and-rollback-in-a-postgresql-function/48277708#48277708 suggest that on PostgreSQL, once something fails inside a transaction, all queries in the current transaction are ignored, and
COMMITsimply does aROLLBACK. Let's check. Yup, true for Postgres, but false for SQLite, SQLite just happily runs anything it can, you really needROLLBACKfor it. - SQL isolation level example
- nodejs/sequelize/raw/commit_error.js: stackoverflow.com/questions/27245101/why-should-we-use-rollback-in-sql-explicitly/27245234#27245234 and stackoverflow.com/questions/48277519/how-to-use-commit-and-rollback-in-a-postgresql-function/48277708#48277708 suggest that on PostgreSQL, once something fails inside a transaction, all queries in the current transaction are ignored, and
- GROUP BY and SQL aggregate functions:
- nodejs/sequelize/raw/group_by_extra_column.js: let's see if it blows up or not on different DB systems,
sqlite3Node.js package allows it:- github.com/sequelize/sequelize/issues/5481#issuecomment-964387232
- dba.stackexchange.com/questions/141594/how-select-column-does-not-list-in-group-by-clause/141600 says that it was allowed in SQL:1999 when there are no ambiguities due to constraints, e.g. when grouping by unique columns
- github.com/postgres/postgres/blob/REL_13_5/src/test/regress/sql/functional_deps.sql#L27 shows that PostgreSQL wants it to work for
UNIQUE NOT NULL, but they just haven't implemented it as of 13.5, where it only works if you group byPRIMARY KEY - dba.stackexchange.com/questions/158015/why-can-i-select-all-fields-when-grouping-by-primary-key-but-not-when-grouping-b also says that
UNIQUE NOT NULLdoesn't work. Dan Lenski then points to a rationale mailing list thread.
- nodejs/sequelize/raw/group_by_max_full_row.js: here we try to get the full row of each group at which a given column reaches the max of the group
- Postgres: has
SELECT DISCINTCT ONwhich works perfectly if you only want one row in case of multiple rows attaining the max.ONis an extension to the standard unfortunately: www.postgresql.org/docs/9.3/sql-select.html#SQL-DISTINCT Docs specify that it always respectsORDER BYwhen selecting the row.- stackoverflow.com/questions/586781/postgresql-fetch-the-row-which-has-the-max-value-for-a-column asks it without the multiple matches use case
- stackoverflow.com/questions/586781/postgresql-fetch-the-rows-which-have-the-max-value-for-a-column-in-each-group/587209#587209 also present in simpler form at stackoverflow.com/questions/121387/fetch-the-rows-which-have-the-max-value-for-a-column-for-each-distinct-value-of/123481#123481 gives a very nice OUTER JOIN only solution! Incredible, very elegant.
- dba.stackexchange.com/questions/171938/get-only-rows-with-max-group-value asks specifically the case of multiple matches to the max
- stackoverflow.com/questions/586781/postgresql-fetch-the-row-which-has-the-max-value-for-a-column asks it without the multiple matches use case
- SQLite:
- stackoverflow.com/questions/48326957/row-with-max-value-per-group-sqlite
- stackoverflow.com/questions/48326957/row-with-max-value-per-group-sqlite/48328243#48328243 teaches us that in SQLite min and max are magic and guarantee that the matching row is returned
- stackoverflow.com/questions/48326957/row-with-max-value-per-group-sqlite/72996649#72996649 Ciro Santilli uses the magic of
ROW_NUMBER
- stackoverflow.com/questions/17277152/sqlite-select-distinct-of-one-column-and-get-the-others/71924314#71924314 get any full row without specifying which, we teach how to specify
- code.djangoproject.com/ticket/22696 WONTFIXed
DISTINCT ON- stackoverflow.com/questions/50846722/what-is-the-difference-between-postgres-distinct-vs-distinct-on/72997494#72997494
DISTINCTvsDISTINCT ON, somewhat related question
- stackoverflow.com/questions/50846722/what-is-the-difference-between-postgres-distinct-vs-distinct-on/72997494#72997494
- stackoverflow.com/questions/48326957/row-with-max-value-per-group-sqlite
- stackoverflow.com/questions/5803032/group-by-to-return-entire-row asks how to take the top N with distinct after order limit. I don't know how to do it in Postgres
- Postgres: has
- nodejs/sequelize/raw/most_frequent.js: illustrates a few variants of findind the mode, including across GROUP
- nodejs/sequelize/raw/group_by_max_n.js: get the top N in each group
- nodejs/sequelize/raw/group_by_extra_column.js: let's see if it blows up or not on different DB systems,
- order results in the same order as
IN: - LIMIT by a running total: TODO links
Leads to the Proca equation.
Schrödinger equation solution for the helium atom by 
Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01No closed form solution, but good approximation that can be calculated by hand with the Hartree-Fock method, see hartree-Fock method for the helium atom.
Bibliography:
Wealth distribution in the United States by Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01www.cbpp.org/wealth-concentration-has-been-rising-toward-early-20th-century-levels-2 shows historical for top 1% and 0.5% from 1920 to 2010.
TODO why is it so hard to find a proper cumulative distribution function-like curve? OMG. This appears to be also called a Lorenz curve.
Wealth Inequality in America by politizane
. Source. Quantum numbers appear directly in the Schrödinger equation solution for the hydrogen atom.
However, it very cool that they are actually discovered before the Schrödinger equation, and are present in the Bohr model (principal quantum number) and the Bohr-Sommerfeld model (azimuthal quantum number and magnetic quantum number) of the atom. This must be because they observed direct effects of those numbers in some experiments. TODO which experiments.
E.g. The Quantum Story by Jim Baggott (2011) page 34 mentions:This refers to forbidden mechanism. TODO concrete example, ideally the first one to be noticed. How can you notice this if the energy depends only on the principal quantum number?
As the various lines in the spectrum were identified with different quantum jumps between different orbits, it was soon discovered that not all the possible jumps were appearing. Some lines were missing. For some reason certain jumps were forbidden. An elaborate scheme of ‘selection rules’ was established by Bohr and Sommerfeld to account for those jumps that were allowed and those that were forbidden.
Quantum Numbers, Atomic Orbitals, and Electron configurations by Professor Dave Explains (2015)
Source. He does not say the key words "Eigenvalues of the Schrödinger equation" (Which solve it), but the summary of results is good enough.Integrations React integration:
- github.com/shakacode/react_on_rails: webpack and server-side rendering
- github.com/reactjs/react-rails Official on the React side only. Demo app linked from package: github.com/BookOfGreg/react-rails-example-app and how it fails: github.com/BookOfGreg/react-rails-example-app/issues/30... The related projects section has some good links:
- shakacode/react_on_rails
- github.com/hyperstack-org/hyperstack transpiles Ruby to JavaScript + React. What could possibly go wrong? :-)
Some key specs:
- SoC:
- name: RP2040. Custom designed by Raspberry Pi Foundation, likely the first they make themselves rather than using a Broadcom chip. But the design still is closed source, likely wouldn't be easy to open source due to the usage of closed proprietary IP like the ARM
- dual core ARM Cortex-M0+
- frequency: 2 kHz to 133 MHz, 125 MHz by default
- memory: 264KB on-chip SRAM
- GPIO voltage: 3.3V
www.physics.udel.edu/~jim/PHYS424_17F/Class%20Notes/Class_5.pdf by James MacDonald shows it well.
And then we can prove the ladder properties easily.
The commutator appear in the middle of this analysis.
An Introduction to QED and QCD by Jeff Forshaw (1997) by Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01www.hep.man.ac.uk/u/forshaw/NorthWest/QED.pdf web.archive.org/web/20200824083133/http://www.hep.man.ac.uk/u/forshaw/NorthWest/QED.pdf
These seem very direct and not ultra advanced, good read.
Quantum Field Theory for The Gifted Amateur by Tom Lancaster (2015) by Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-11 +Created 1970-01-01 Unlisted articles are being shown, click here to show only listed articles.