Tag Archives: SQL

Write a SQL query to find all duplicate emails in a table named Person. +----+---------+ | Id | Email | +----+---------+ | 1 | a@b.com | | 2 | c@d.com | | 3 | a@b.com | +----+---------+ For example, your query should return the following for the above table: +---------+ | Email | +---------+ | a@b.com | +---------+ Note: All ...

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I’ve been thinking about this since 2007, somewhere around the time S3 was launched by Amazon. I even tried to implement it a few times, but failed right after the design phase. I’ve heard about a startup, which tried to do it too, but also failed. I’m still not sure whether it’s possible to do, but it could definitely become ...

Previously we set up two EntityManagers in the same application. One for the reads and one for the writes. Now it’s time to create our read repository. The read only repository will use the secondary read only EntityManager. In order to make it a read only repository, it is essential not to have any save and persist actions. 01 02 ...

Our previous setup works as expected. What we shall do now is to get one step further and configure two separate entity managers without affecting the functionality we achieved previously. The first step would be to set the default entity manager configuration to a primary one.This is the first step 01 02 03 04 05 06 07 08 09 10 ...

In our previous post we set up multiple PostgreSQL instances with the same data.Our next step would be to configure our spring project by using the both servers. As stated previously we shall use some of the code taken from the Spring Boot JPA post, since we use exactly the same database. This shall be our gradle build file 01 ...

This post is part of a series where I do my best to organize my thoughts around Go: its paradigms and usability as a programming language. I write this as a Java programmer that respects the principles of Elegant Objects. I am studying the Go Code Review mantra Accept Interfaces, Return Structs and was inspired to write this post after ...

Digital marketing platforms are teeming with an ever-increasing array of marketing software that you can use to stay competitive and keep up with the demands of the increasingly tech-savvy users. Today’s digital marketing is largely data-driven, and to have an edge over the competition, you need to use the right software on the various marketing platforms wisely and decisively to ...

We do use a lot of h2 with spring especially for unit tests. However instead of unit tests we might want to have a fully functional prototype with data to display. H2 is the perfect candidate for that, it works great with spring, it has good syntax compatibility with most databases out there and it also provides you with a ...