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.
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.
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.
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.
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.
Introduction In this article, I’m going to explain why you should always use the Hibernate Dynamic Update feature for entities that map JSON properties. Since Hibernate ORM does not offer support for JSON column types, we are going to use the Hibernate Types library, which provides a JsonType that allows you to map String, Map, List, JsonNode, Java Records, or POJOs on JSON columns, no matter if you are using PostgreSQL, MySQL, Oracle, SQL Server, or H2.
Introduction In this article, we are going to see how SQL Server Foreign Key constraints are locking the parent record when executing a child record UPDATE. This situation is specific to SQL Server and happens even when using the Read Committed Snapshot Isolation level.