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.
SQL ORDER BY RANDOM
Introduction In this article, we are going to see how we can sort an SQL query result set using an ORDER BY clause that takes a RANDOM function provided by a database-specific function. This is a very handy trick, especially when you want to shuffle a given result set. Note that sorting a large result set using a RANDOM function might turn out to be very slow, so make sure you do that on small result sets. If you have to shuffle a large result set and limit it afterward, then it’s… Read More
How to implement a database job queue using SKIP LOCKED
Introduction In this article, we are going to see how we can implement a database job queue using SKIP LOCKED. I decided to write this article while answering this Stack Overflow question asked by Rafael Winterhalter. Since SKIP LOCKED is a lesser-known SQL feature, it’s a good opportunity to show you how to use it and why you should employ it, especially when implementing a job queue task.
How does a relational database execute SQL statements and prepared statements
Introduction In this article, we are going to see how a relational database executes SQL statements and prepared statements.
How to map a PostgreSQL Range column type with JPA and Hibernate
Introduction In this article, we are going to see how to map the PostgreSQL range column types with JPA and Hibernate. Luckily, you don’t have to implement a custom Hibernate type for the PostgreSQL range column type since the hibernate-types project already provides support for it.
How to map a PostgreSQL HStore entity property with JPA and Hibernate
Introduction The open-source hibernate-types project allows you to map a great variety of database types that are not supported natively by Hibernate ORM (e.g. JSON, ARRAY, YearMonth, Month, INET addresses). In this article, we are going to see how you can map a PostgreSQL HStore type, which allows you to store key/value pairs, to a Java Map entity property when using JPA and Hibernate.
How to map a PostgreSQL Enum ARRAY to a JPA entity property using Hibernate
Introduction The open-source hibernate-types project allows you to map JSON, ARRAY, YearMonth, Month or database-specific columns (e.g. INET addresses). In this article, we are going to see how you can map a PostgreSQL Enum ARRAY type to a Java array entity property when using JPA and Hibernate.
How to map the PostgreSQL inet type with JPA and Hibernate
Introduction In this article, we are going to see how to map the PostgreSQL inet type with JPA and Hibernate. Traditionally, PostgreSQL has been offering more column types than other relational database systems. Previously, I showed you how to map JSON and ARRAY as Hibernate Types, and mapping the PostgreSQL inet type is going to be just as easy. You don’t even have to implement these types since they are available via the hibernate-types project.
Hibernate database schema multitenancy
Introduction As I explained in this article, multitenancy is an architectural pattern which allows you to isolate customers even if they are using the same hardware or software components. There are multiple ways you can achieve multitenancy, and in this article, we are going to see how you can implement a multitenancy architecture using the database schema as the unit of isolation.
A beginner’s guide to database multitenancy
Introduction In software terminology, multitenancy is an architectural pattern which allows you to isolate customers even if they are using the same hardware or software components. Multitenancy has become even more attractive with the widespread adoption of cloud computing. A relational database system provides a hierarchy structure of objects which, typically, looks like this: catalog -> schema -> table. In this article, we are going to see how we can use each of these database object structures to accommodate a multitenancy architecture.
