Incoming links: Sequelize raw query
@cirosantilli/_file/nodejs/sequelize/nodejs/sequelize/parallel_select_and_update.js Updated 2024-12-15 +Created 1970-01-01
This example is the same as nodejs/sequelize/raw/parallel_select_and_update.js, but going through Sequelize rather than with Sequelize raw queries.
NONE is not supported for now to not have a transaction at all because lazy.The examples illustrates: stackoverflow.com/questions/55452441/for-share-and-for-update-statements-in-sequelize
Sample invocation:where:
node --unhandled-rejections=strict ./parallel_select_and_update.js p 10 100 READ_COMMITTED UPDATEREAD_COMMITTED: one of the keys documented at: sequelize.org/master/class/lib/transaction.js~Transaction.html which correspond to the standard sQL isolation levels. It not given, don't set one, defaulting to the database's/sequelize's default level.UPDATE: one of the keys documented at: sequelize.org/master/class/lib/transaction.js~Transaction.html#static-get-LOCK. Update generates aSELECT FOR UPDATEin PostgreSQL for example. If not given, don't use anyFOR xxxexplicit locking.
Other examples:
node --unhandled-rejections=strict ./parallel_select_and_update.js p 10 100 READ_COMMITTED UPDATE
Then, the outcome is exactly as described at: nodejs/sequelize/raw/parallel_select_and_update.js:
READ_COMMITTED: failsREAD_COMMITTED UPDATE: worksREPEATABLE_READ: works, but is a bit slower, as it does rollbacksThis case also illustrates Sequelize transaction retries, since in this transaction isolation level transactions may fail:
Exampes under nodejs/sequelize/raw:
- nodejs/sequelize/raw/index.js: Sequelize raw query hello world. Ideally one should never use a raw query in a real project. We use raw examples mostly as a SQL tutorial under SQL example, and will not comment on them much further on this section.