Db

A lot of boilerplate code is written when developers need to test their applications with different connected systems like databases, stream platforms and other collaborators. Docker allows to handle those dependencies but there is still some glue code required to bind the container’s lifecycle and the configuration to the concrete integration test. Testcontainers is a testing library that offers lightweight throwaway instances of anything able to run in a Docker container, with bindings to configure the specific containers and also provides wrappers to manage our own custom containers. ...

JetstreamDB is a in-memory database engine for Java that claims to be built for ultra-high speed and the ability of managing complex data structures by storing real Java objects instead of serializing data structures to other database specific formats. In the following short example I would like to demonstrate how to create and read items from such a database by building a small article management sample app. ...

HipChat is Atlassian’s alternative to Slack and its solution to team collaboration chats. Atlassian Connect offers developer tools to bootstrap applications, connect to Atlassian’s cloud products with easy and in combination with HipChat’s REST APIs allows us to write integrations for such a chat server in no time. In the following tutorial I’d like to show how to write an integration within a few steps using Atlassian Connect, Node.js and Express and how to connect the integration to a HipChat server. ...

I have written about other database migration frameworks before but in this article I’d like to cover the Liquibase framework in combination with WildFly as Java EE 7 compatible application server. In the following tutorial, we’re going to write a full Java EE 7 book store application with a few steps and with Liquibase on board to create the database structure and insert example data into the database. Thanks to the WildFly Maven Plug-in we even do not need to download and configure the application server but let Maven and the plug-in do the work for us. ...

Database migrations often are a necessity in the application development and maintenance life-cycle. Whenever we need to apply changes to the database structure, insert new data fragments and in doing so want to be sure that this all happens with some control and versioning. The following tutorial shows how implement this for a simple Java EE 6 web application to be run on a GlassFish application server in a few quick steps using the Flyway framework, an eager initialized Singleton EJB and some Maven wiring. ...

Get size of a table SELECT pg_size_pretty(pg_total_relation_size('schemaname.tablename')); Select unique combination of fields / tuples SELECT DISTINCT ON(field1, field2) field1, field2 FROM thetable Select rows where a combination of fields is not unique SELECT columnA, columnB, count(*) AS count FROM thetable GROUP BY columnA, columnB HAVING count(*) > 1 Search for rows with array containing value Assuming, the field appointments has the type date[] SELECT * FROM mtable WHERE appointments @> ARRAY['2023-09-19'::date] ...