CREATE OR REPLACE TRIGGER tr_reg_cou AFTER update OF region_id ON regions FOR EACH ROW BEGIN DBMS_OUTPUT.PUT_LINE('旧的region_id值是'||:old.region_id ||'、新的region_id值是'||:new.region_id); UPDATE countries SET region_id = :new.region_id WHERE region_id = :old.region_id; E...
A quick tutorial of some simple and not-so-simple CRUD - create, read, update, and delete. LATERAL JOIN “This is a perfect scenario for a lateral join!” Have you ever heard that? If you were wondering “what’s a lateral join?” This will help. It’s pretty simple, but the co...
摘要:When working with databases, it seems inevitable that you will find yourself needing to export data from a table to send along to another team, compan 阅读全文 posted @ 2020-07-30 15:12 Zhentiw 阅读(203) 评论(0) 推荐(0) [...
For INSERT/UPDATE/DELETE with RETURNING, PL/pgSQL reports an error for more than one returned row, even when STRICT is not specified. This is because there is no option such as ORDER BY with which to determine which affected row should be returned. If print_strict_params is enabled for...
But that’s not what’s causing the performance difference.While MySQL services the entire aggregate (count(*)) from the index, Postgres actually goes to the heap to get every row. The heap contains the entire row, which is upwards of 1 KiB. This is expensive, and when the heap cache ...
Bug description When using meta DB is failing on every query we do at a table that has a PostGIS geometry. superset_app | /app/superset/extensions/metadb.py:322: SAWarning: Did not recognize type 'geometry' of column 'geometry' Screensho...
Amit specialty is working in Database Internals (SQL Engine, Storage Engine, and Replication), and is known for setting up teams from scratch for R&D work. View all Amit's blog posts Our Migration Portal helps you assess the effort required to move to the enterprise-built version of ...
updateOrCreateBy(field, data, txn); await Model.query().count(txn); await Model.query().first(txn); await Model.query().select(txn); await Model.query().update(fields, txn); // Instance methods await model.save(txn); await model.destroy(txn); await model.destroyCascade(txn); // ...
In this article, we'll give a brief overview of SVG, when to use it (and when not to), and how to use it effectively in a React application. We'll also briefly touch on how to integrate with d3 (which comes in very useful when working with SVG). We relied heavily on SVG to ...
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