A Guide to SQL Naming Conventions
One of Java’s big strengths, in my opinion, is the fact that most naming conventions have been established by the creators of the language. For example: Class names are in PascalCase Member names are...
View ArticleStop Mapping Stuff in Your Middleware. Use SQL’s XML or JSON Operators Instead
It’s been a while since I’ve ranted on this blog, but I was recently challenged by a reddit thread to write about this topic, so here goes… So, you’re writing a service that produces some JSON from...
View ArticleSQL DISTINCT is not a function
A very common misconception I often encounter with SQL users is the idea that DISTINCT is something like a function, and that it can take parenthesised arguments. Just recently, I’ve seen this Stack...
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5 Ways to Better Understand SQL by Adding Optional Parentheses
It appears that our recent beginner SQL articles explaining SQL syntax were quite popular. These include: A Beginner’s Guide to the True Order of SQL Operations A Probably Incomplete, Comprehensive...
View ArticleCreate Empty Optional SQL Clauses with jOOQ
When using jOOQ to create dynamic SQL statements (one of jOOQ’s core value propositions), it is often necessary to add query elements conditionally, with a default “No-op” behaviour. For first time...
View ArticleThe Many Flavours of the Arcane SQL MERGE Statement
The SQL MERGE statement is a device whose mystery is only exceeded by its power. A simple example shows its full power according to standard SQL. Imagine you have a production table for product prices,...
View ArticleUsing SQL Server FOR XML and FOR JSON Syntax on Other RDBMS With jOOQ
SQL Server supports transforming flat tabular SQL result sets into hierarchical structures by convention using the convenient FOR XML or FOR JSON syntaxes. This is really convenient and less verbose...
View ArticleUse NATURAL FULL JOIN to compare two tables in SQL
There are a few ways to compare two similar tables in SQL. Assuming PostgreSQL syntax, we might have this schema: CREATE TABLE t1 (a INT, b INT, c INT); CREATE TABLE t2 (a INT, b INT, c INT); INSERT...
View ArticleHaving “constant” columns in foreign keys
I was asked a very interesting question on Twitter just now: @lukaseder quick q: in pg can I have a composite foreign key where one value is a constant… or do I have to store the constant in the table?...
View ArticleNesting Collections With jOOQ 3.14’s SQL/XML or SQL/JSON support
One of the main features of ORMs is M as in Mapping. Libraries like jOOQ help auto-mapping flat or nested database records onto Java classes that have the same structure as the SQL result set. The...
View ArticleAutomatically Transform Oracle Style Implicit Joins to ANSI JOIN using jOOQ
While jOOQ is mostly being used as an internal SQL DSL for embedded, dynamic SQL in Java, where it offers the best solution on the market, jOOQ is increasingly also used for one of its secondary...
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jOOQ Internals: Pushing up SQL fragments
Over the past 13 years, jOOQ has accrued quite some internal features, which you, the user, are not exposed to. One very interesting feature is the capability for any arbitrary jOOQ expression tree...
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Implementing a generic REDUCE aggregate function with SQL
So, @rotnroll666 nerd sniped me again. Apparently, the Neo4j Cypher query language supports arbitrary reductions, just like any functional collection API, oh say, the JDK Stream API: Stream.of(2, 4,...
View ArticleTranslating Stored Procedures Between Dialects
In the past years, we’ve invested a lot of effort into improving our procedural language capabilities in jOOQ. What started with a simple internal API to support the emulations of DDL clauses like...
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Calculating Pagination Metadata Without Extra Roundtrips in SQL
When paginating results in SQL, we use standard SQL OFFSET .. FETCH or a vendor specific version of it, such as LIMIT .. OFFSET. For example: SELECT first_name, last_name FROM actor ORDER BY actor_id...
View ArticleUse IN List Padding to Your JDBC Application to Avoid Cursor Cache Contention...
A problem few developers are aware of is the possibility of running into “cursor cache contention” or “execution plan cache contention” problems when using IN lists in SQL. The problem that is...
View ArticleHow to Get an RDBMS Server Version with SQL
Do you need to know what RDBMS Server version you’re on, and you only have SQL at your disposal? No problem. Most RDBMS provide you with that information in some form of meta data table. Here’s how:...
View ArticlejOOQ 3.15’s New Multiset Operator Will Change How You Think About SQL
This is how SQL should have been used all along. They called it The Third Manifesto, ORDBMS, or other things. Regrettably, it never really took off. Because most vendors didn’t adopt it. And those who...
View ArticleReactive SQL with jOOQ 3.15 and R2DBC
One of the biggest new features of the recently released jOOQ 3.15 is its new support for reactive querying via R2DBC. This has been a highly popular feature request, and we finally delivered on it....
View ArticleStandard SQL/JSON – The Sobering Parts
It’s been almost 1 year now since jOOQ 3.14 was released in October 19, 2020 with SQL/JSON (and SQL/XML) support. Half a year later, we’ve released jOOQ 3.15 with MULTISET support, which builds on top...
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