May 06
Proxy Pattern: “Proxy is a structural design pattern that lets you provide a substitute or placeholder for another object. A proxy controls access to the original object, allowing you to perform something either before or after the request gets through to the original object.” “A credit card is a proxy for a bank account, which …
May 06
Façade Pattern “Facade is a structural design pattern that provides a simplified interface to a library, a framework, or any other complex set of classes.” “When you call a shop to place a phone order, an operator is your facade to all services and departments of the shop. The operator provides you with a simple …
May 06
Decorator Design pattern: Decorator is a structural design pattern that lets you attach new behaviors to objects by placing these objects inside special wrapper objects that contain the behaviors. Example: Assume: A notifier class/object can send only email messages. But the application at a later time may want to use text/SMS, FB, or similar messages. …
May 06
Adapter Design Patterns Ref: A good read: https://refactoring.guru/design-patterns/adapter Ref: Wikipedia Ref: https://www.visual-paradigm.com/guide/uml-unified-modeling-language/uml-aggregation-vs-composition/
May 05
MicroK8s Commands in Ubuntu (- – use double hyphen) Install sudo snap install microk8s – -classic sudo snap install microk8s – -classic – -channel=1.25/stable Allow Through: Firwall sudo ufw allow in on cni0 && sudo ufw allow out on cni0 sudo ufw default allow routed Enable Add Ons microk8s enable dns microk8s enable dashboard microk8s …
May 04
Group By group by attr1, attr2 group by ROLLUP(attr1, attr2) group by CUBE(attr1, attr2) Rank, Dense_RANK, ROW_number: RANK() OVER (ORDER BY PRICE) as "PR", ROW_NUMBER() OVER (ORDER BY PRICE) as "PR" DENSE_RANK() OVER (ORDER BY C DESC NULLS LAST) as "R" DENSE_RANK() OVER (PARTITION by C ORDER BY P) as "PR" RANK() OVER (ORDER BY …
