The Hibernate forum is a never-ending source of inspiration when it comes to solving real-life problems you might bump into when developing an enterprise application.
For instance, this post asks about a JPQL query which should fetch a given parent entity when all its child entities match the given filtering criteria.
Continue reading “How to query parent rows when all children must match the filtering criteria with SQL and Hibernate”
Vladimir Sitnikov has been working on many optimizations to the PostgreSQL JDBC Driver, and one of these is the
reWriteBatchedInserts configuration property which he recently told me about.
In this article, you will see how the
reWriteBatchedInserts JDBC configuration property works in PostgreSQL, and how it allows you to rewrite INSERT statements into a multi-VALUE INSERT.
Continue reading “How to enable multi-row inserts with the PostgreSQL reWriteBatchedInserts configuration property”
Answering questions on the Hibernate forum is a neverending source of inspiration. The following question is about joining unrelated entities using entity queries, and this post is going to explain how you can do it when using JPA and Hibernate.
Continue reading “How to JOIN unrelated entities with JPA and Hibernate”
Hibernate custom Types allow you to map all sorts of database specific column types, like IP address, JSON columns, bit sets or SQL arrays.
There are two ways to define a custom Hibernate Type:
The latter option is preferred since it allows you to better split the Java-to-JDBC and the JDBC-to-SQL type handling. In this article, we are going to see how you can map SQL arrays to their Java counterpart.
Continue reading “How to map Java and SQL arrays with JPA and Hibernate”
Each database application is unique. While most of the time, deleting a record is the best approach, there are times when the application requirements demand that database records should never be physically deleted.
So who uses this technique?
For instance, StackOverflow does it for all Posts (e.g. Questions and Answers). The StackOverflow
Posts table has a
ClosedDate column which acts as a soft delete mechanism since it hides an Answer for all users who have less than 10k reputation.
If you’re using Oracle, you can take advantage of its Flashback capabilities, so you don’t need to change your application code to offer such a functionality. Another option is to use the SQL Server Temporal Table feature.
However, not all relational database systems support Flashback queries, or they allow you to recover a certain record without having to restore from a database backup. In this case, Hibernate allows you to simplify the implementation of soft deletes, and this article is going to explain the best way to implement the logical deletion mechanism.
Continue reading “The best way to soft delete with Hibernate”