SQL Operation Order
Introduction In this article, we are going to see what is the standard SQL operation order. Once you understand the order in which SQL operations are executed, then it will be clear why the Oracle legacy pagination query required a Derived Table in order to make sure that the ROWNUM pseudocolumn is computed after executing the ORDER BY clause.
Testcontainers Database Integration Testing
Introduction In this article, we are going to see how we can use Testcontainers for database integration testing. If you are still using HSQLDB or H2 to test your Spring Boot application that runs on Oracle, SQL Server, PostgreSQL or MySQL in production, then you are better off switching to Testcontainers.
The best way to map MonetaryAmount with JPA and Hibernate
Introduction In this article, we are going to see what is the best way to map the MonetaryAmount object from Java Money and the Currency API when using JPA and Hibernate. While the Java Money and Currency API define the specification, like the MonetaryAmount interface, the Moneta project provides a reference implementation for this API.
Maximum number of database connections
Introduction Have you ever wondered what the maximum number of database connections provided by a given RDBMS is? In this article, we are going to see what limits the number of database connections, no matter if you’re using Oracle, SQL Server, PostgreSQL, or MySQL.
Default Database Primary, Foreign, and Unique Key Indexing
Introduction In this article, we are going to see what is the default database Primary, Foreign, and Unique Key indexing strategy when using Oracle, SQL Server, PostgreSQL, and MySQL. So, if you are wondering whether one of those top relational databases creates a default index whenever you are adding a Primary Key, Foreign Key, or Unique Key constraint, then this article is going to provide you with the answer you’ve been waiting for.
SQL Recursive WITH CTE queries
Introduction In this article, we are going to see how SQL Recursive WITH CTE (Common Table Expression) queries work and how we can apply them for processing hierarchical data models.
SQL CROSS APPLY – A Beginner’s Guide
Introduction In this article, we are going to see how the SQL CROSS APPLY works and how we can use it to cross-reference rows from a subquery with rows in the outer table and build compound result sets. CROSS APPLY is basically equivalent to the LATERAL JOIN, and it’s been supported by SQL Server since version 2005 and Oracle since version 12c.
SQL Derived Table or Inline View
Introduction In this article, we are going to see what an SQL Derived Table or Inline View is and how you can use it to bypass the standard SQL operation order. While the SQL Standard uses the term Derived Table for this feature, some relational database systems call it Inline View.
SQL CTE – Common Table Expression
Introduction In this article, we are going to see what an SQL CTE (Common Table Expression) is and how you can use it to reuse subquery result sets or inline views.
SQL Seek Method or Keyset Pagination
Introduction In this article, we are going to see what the SQL Seek Method or Keyset Pagination is and why you should consider it when navigating over large results sets. The goal of pagination is to avoid fetching large volumes of data since the UI has a limited viewport that could be used to display data.
