Add notes for managing databases, ERPNext commands, and WordPress migration

Author: ksobrenat32

docs/sysadmin/databases-notes.md

@@ -0,0 +1,54 @@
+# Databases notes
+
+## Managing Databases with Docker
+
+When using databases within Docker containers, it's essential to manage data persistence and backups effectively.
+
+### Get an sql prompt inside a running container
+
+For MySQL/MariaDB:
+
+```sh
+docker exec -it container_name mysql -u root -p
+docker exec -it container_name mariadb -u root -p
+```
+
+## Tips and Tricks
+
+### Cleaning Largest Tables
+
+In order to identify the largest tables in your database, you can use the following SQL query:
+
+```sql
+SELECT table_schema as `Database`, table_name AS `Table`, round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB` FROM information_schema.TABLES ORDER BY (data_length + index_length) DESC;
+```
+
+Create a stored procedure to clean old logs from a specific table (`tabName` in this example) in batches to avoid long locks:
+
+```sql
+USE database_name; -- Get it with show databases;
+DELIMITER $$
+
+CREATE OR REPLACE PROCEDURE clean_old_logs()
+BEGIN
+    DECLARE rows_affected INT DEFAULT 1;
+
+    WHILE rows_affected > 0 DO
+        DELETE FROM `tabName`
+        WHERE creation < NOW() - INTERVAL 3 DAY
+        LIMIT 500;
+
+        SET rows_affected = ROW_COUNT();
+    END WHILE;
+END$$
+
+DELIMITER ;
+
+CALL clean_old_logs();
+```
+
+Optimize the table you need after cleaning:
+
+```sql
+OPTIMIZE TABLE `tabName`;
+```

docs/sysadmin/erpnext-notes.md

@@ -0,0 +1,89 @@
+# Erpnext notes
+
+I mainly use the Docker installation of ERPNext, so these notes are focused on that setup.
+
+## General commands for Frappe/ERPNext with Docker
+
+### Get a python prompt inside a running container
+
+```sh
+sudo docker exec -it container_name_backend bench --site frontend console
+```
+
+### When updating
+
+If the image is updated, the database needs to be migrated.
+
+```sh
+sudo docker exec -it container_name_backend bench --site frontend migrate
+```
+
+### When frontend is not loading properly
+
+```sh
+sudo docker exec -it container_name_backend bench --site frontend clear-cache
+sudo docker exec -it container_name_backend bench --site frontend clear-website-cache
+sudo docker exec -it container_name_redis_queue redis-cli flushall
+sudo docker exec -it container_name_redis_cache redis-cli flushall
+```
+
+### Change variant template
+
+Sometimes in ERPNext, an item variant may be incorrectly linked to the wrong template. The following Python scripts can be used within the Frappe framework to correct this issue.
+
+**If the item has no links:**
+
+```python
+def update_variant_template(variant_to_fix, correct_template):
+    # Fetch the variant document
+    doc = frappe.get_doc("Item", variant_to_fix)
+
+    # Update the variant_of field
+    doc.variant_of = correct_template
+
+    # Save the changes
+    doc.save()
+
+    # Commit to apply changes to the database
+    frappe.db.commit()
+
+    print(f"Updated Item {variant_to_fix}: Now a variant of {correct_template}")
+```
+
+**If the item has links and cannot be changed directly:**
+
+```python
+def clone_variant_fix_template(old_variant, correct_template):
+    # Fetch existing variant
+    old_doc = frappe.get_doc("Item", old_variant)
+
+    # Generate a new unique item code
+    new_item_code = make_autoname(f"{old_variant}-.#####")
+
+    # Create a new variant with the correct template
+    new_doc = frappe.copy_doc(old_doc)
+    new_doc.variant_of = correct_template
+    new_doc.item_code = new_item_code  # Assign a unique item code
+    new_doc.insert()
+
+    # Deactivate old variant to prevent further usage
+    old_doc.disabled = 1
+    old_doc.save()
+
+    # Commit to apply changes to the database
+    frappe.db.commit()
+
+    print(f"Created new variant {new_doc.name} ({new_item_code}) under {correct_template} and disabled {old_variant}.")
+```
+
+**Example usage:**
+
+```python
+# Update a single variant
+update_variant_template("variant_code", "template_code")
+
+# Clone a variant and fix the template
+clone_variant_fix_template("variant_code", "template_code")
+```
+
+

docs/sysadmin/wordpress-notes.md

@@ -0,0 +1,45 @@
+# Wordpress Notes
+
+This document contains various notes and configurations related to managing and maintaining WordPress installations.
+
+## Migration
+
+When migrating a WordPress site from one server to another, consider the following steps:
+
+1. **Backup Files and Database**: Ensure you have a complete backup of your WordPress files and database.
+    - The files to back up include the entire WordPress directory, typically located at `/var/www/html/your-site`.
+    - The database can be backed up using tools like `mysqldump`
+
+```sh
+mysqldump -u username -p database_name > backup.sql
+```
+
+2. **Transfer Files**: Use `rsync` or `scp` to transfer the WordPress files to the new server.
+
+```sh
+rsync -avz /path/to/wordpress/ user@newserver:/path/to/destination/
+```
+
+3. **Import Database**: On the new server, create a new database and import the backup.
+
+```sh
+mysql -u username -p new_database_name < backup.sql
+```
+
+4. **Update wp-config.php**: Modify the `wp-config.php` file on the new server to reflect the new database credentials.
+
+5. **Update Site URL**: If the domain name has changed, update the site URL in the database. You can do this using wp-cli:
+
+```sh
+# Migrate http to https
+docker run --rm --volumes-from wp-container --network container:wp-container wordpress:cli search-replace 'http://original.domain' 'https://new.domain'
+# Migrate https to https
+docker run --rm --volumes-from wp-container --network container:wp-container wordpress:cli search-replace 'https://original.domain' 'https://new.domain'
+# Migrate any remaining references
+docker run --rm --volumes-from wp-container --network container:wp-container wordpress:cli search-replace 'original.domain' 'new.domain'
+# Flush cache
+docker run --rm --volumes-from wp-container --network container:wp-container wordpress:cli cache flush
+```
+
+Remember to recreate any cache of the extensions you are using.
+