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Showing posts from December, 2024

Mastering Django ORM Update Queries — From Basics to Pro Level

Updating data properly is just as important as selecting data. In this guide, you will learn how to update records correctly in Django ORM — from basic .save() usage to pro techniques like atomic updates, bulk updates, F expressions, and best practices! 📚 1. Basic Update Using .save() Fetch and modify a single object user = NewUser.objects.get(pk=1) user.email = 'newemail@example.com' user.save() ⚡ 2. Updating Specific Fields with .save(update_fields=[...]) user = NewUser.objects.get(pk=1) user.email = 'newemail@example.com' user.save(update_fields=['email']) 🎯 3. Updating Multiple Records at Once Using .update() NewUser.objects.filter(user_type=2).update(is_active=False) 🧠 4. .save() vs .update() — Key Differences Aspect .save() .update() Works on Single object QuerySet (multiple) Triggers signals? ✅ Yes ❌ No Auto-updates auto_now fields? ✅ Yes ❌ No Custom logic inside save() runs? ✅ Yes ❌ No Speed for bulk ❌ Slow ✅ Fast 🔥 5. Upda...
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How to Install and Manage PostGIS with a Non-Superuser Role

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Prerequisite: PostgreSQL Version This guide assumes you are using PostgreSQL version 14 or later, which supports the necessary commands for PostGIS installation and management. Ensure your PostgreSQL server is up-to-date before proceeding. This guide ensures that PostGIS is installed and configured properly for a specific user, such as administrator , while avoiding common issues. 1. Ensure Superuser Access sudo -i -u postgres psql --dbname=financethat 2. Create a Role for PostGIS Management CREATE ROLE administrator WITH LOGIN PASSWORD 'your_secure_password'; GRANT ALL PRIVILEGES ON DATABASE financethat TO administrator; 3. Install PostGIS To install PostGIS on Ubuntu, first ensure you have the required PostgreSQL version installed. Then, use the following commands: sudo apt update sudo apt install postgis postgresql-14-postgis-3 Replace 14 with your PostgreSQL version if different. After installation, enable PostGIS in...
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