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Showing posts from June, 2021

SQL Joins

You’ll nearly always need to connect many tables if you want to extract anything useful out of data. A join clause in SQL joins columns from one or more tables into a new table, similar to a join operation in relational algebra. In this article, let’s see how the joins work in SQL. We are going to explore the following SQL Joins.   ∘ 1 — (INNER) JOIN   ∘ 2 — LEFT (OUTER) JOIN   ∘ 3 — RIGHT (OUTER) JOIN   ∘ 4 — FULL (OUTER) JOIN AND UNION   ∘ When to use it? Also, I’m going to use the following tables for the above-mentioned SQL Joins. 1 — (INNER) JOIN Returns records with values in both tables that are the same. Image from Author As long as the condition is met, the INNER JOIN keyword selects all rows from both tables. This keyword will produce a result-set by merging all rows from both tables that satisfy the criteria, i.e. the common field’s value will be the same. Syntax: SELECT table1.column1,table1.column2,table2.column1,…. FROM table1 INNER JOIN table2 ON table1.matching_column =

Collection Framework in Java

Data Structure As a definition, the data structure is a specific method of organizing data in a computer so that it may be used efficiently. In this article, we are going to see about the Collection Framework which enables us to implement some important Data Structures available on Java. Topics covered:   ∘ Data Structure   ∘ Collection Framework   ∘ Class vs Interface   ∘ Lists   ∘ Set   ∘ Map   ∘ Difference between List, Set, and Map interface in Java Collection Framework A Java collection is a grouping of separate objects that are represented as a single entity. Java collections, like data, provide all actions such as searching, sorting, insertion, modification, deletion, and so on. Java Collections is a fairly broad topic, and as a newbie, it might be tough to find your way around. We’ve covered all you need to know to get started with Java Collections. Image from  https://www.geeksforgeeks.org/how-to-learn-java-collections-a-complete-guide/ What exactly is a framework in Java? It