SQL INNER JOIN – A Beginner’s Guide
Introduction In this article, we are going to see how INNER JOIN works in SQL, and how we can use it to associate rows belonging to different tables and build compound result sets.
SQL EXISTS and NOT EXISTS
Introduction In this article, we are going to see how the SQL EXISTS operator works and when you should use it. Although the EXISTS operator has been available since SQL:86, the very first edition of the SQL Standard, I found that there are still many application developers who don’t realize how powerful SQL subquery expressions really are when it comes to filtering a given table based on a condition evaluated on a different table.
SQL CROSS JOIN – A Beginner’s Guide
Introduction In this article, we are going to see how a CROSS JOIN works, and we will also make use of this SQL join type to build a poker card game.
A beginner’s guide to database deadlock
Introduction In this article, we are going to see how a deadlock can occur in a relational database system, and how Oracle, SQL Server, PostgreSQL, or MySQL recover from a deadlock situation.
JDBC Driver Maven dependency list
Introduction Ever wanted to connect to a relational database using Java and didn’t know which JDBC Driver Maven dependency to use? If so, this article is surely going to help you from now on.
How to map Oracle JSON columns using JPA and Hibernate
Introduction In this article, we are going to see how to map the Oracle JSON column storage types when using JPA and Hibernate. The Hypersistence Utils project provides a generic JsonType that works with Oracle, SQL Server, PostgreSQL, and MySQL, and it can even use the columnDefinition attribute of the JPA @Column annotation to determine the underlying database column type.
How to get the SQL execution plan on Oracle
Introduction In this article, we are going to see how we can get the SQL execution plan on Oracle. When tuning performance, the execution plan is indispensable as it allows you to understand the operations done by the database when executing a certain SQL query.
How to limit the SQL query result set to Top-N rows only
Introduction In this article, we are going to see how we can limit the SQL query result set to the Top-N rows only. Limiting the SQL result set is very important when the underlying query could end up fetching a very large number of records, which can have a significant impact on application performance.
