Java polymorphism refers to the ability of an object to take on different forms or behaviors depending on the context in which it is used. It allows objects of different classes to be treated as objects of a common superclass. Polymorphism...
Java encapsulation is a fundamental principle of object-oriented programming (OOP) that allows for the bundling of data and methods within a single unit known as a class. It provides the means to protect data from direct access by other classes and...
Java Abstraction is a fundamental concept in object-oriented programming (OOP) that allows you to create complex systems by focusing on essential characteristics while hiding unnecessary details. It is one of the key principles of OOP, along with encapsulation, inheritance, and polymorphism....
Cannot begin/end transactions in PL/pgSQL Rollback The cause of error: Cannot begin/end transactions in PL/pgSQL is the rollback command. The solution is to use exception clause in the function. Wrong function CREATE OR REPLACE FUNCTION update_test (p_old_name varchar, p_new_name varchar) RETURNS...
Column must appear in the GROUP BY clause or be used in an aggregate function GROUP BY clause The cause of error: Column must appear in the GROUP BY clause or be used in an aggregate function The solution is to...
