Java's package private visibility is an underrated feature. When you omit any visibility modifier in Java, then the default (for most objects) is package private, i.e. the object is visible only to types in the same package: class YouDontSeeMe {} class YouDontSeeMeEither {} In fact, a compilation unit (the .java file) can contain multiple such … Continue reading How to Generate Package Private Code with jOOQ’s Code Generator
Author: lukaseder
I made jOOQ
How to Pass a Table Valued Parameter to a T-SQL Function with jOOQ
Microsoft T-SQL supports a language feature called table-valued parameter (TVP), which is a parameter of a table type that can be passed to a stored procedure or function. For example, you may write: CREATE TYPE u_number_table AS TABLE (column_value INTEGER); CREATE FUNCTION f_cross_multiply ( @numbers u_number_table READONLY ) RETURNS @result TABLE ( i1 INTEGER, i2 … Continue reading How to Pass a Table Valued Parameter to a T-SQL Function with jOOQ
How to Turn a List of Flat Elements into a Hierarchy in Java, SQL, or jOOQ
Occasionally, you want to write a SQL query and fetch a hierarchy of data, whose flat representation may look like this: SELECT id, parent_id, label FROM t_directory; The result might be: |id |parent_id|label | |---|---------|-------------------| |1 | |C: | |2 |1 |eclipse | |3 |2 |configuration | |4 |2 |dropins | |5 |2 |features | … Continue reading How to Turn a List of Flat Elements into a Hierarchy in Java, SQL, or jOOQ
3.18.0 Release with Support for more Diagnostics, SQL/JSON, Oracle Associative Arrays, Multi dimensional Arrays, R2DBC 1.0
DiagnosticsListener improvements A lot of additional diagnostics have been added, including the automated detection of pattern replacements, helping you lint your SQL queries irrespective of whether you're using jOOQ to write your SQL, or if you're using it as a JDBC / R2DBC proxy for an existing application. A lot of these diagnostics are available … Continue reading 3.18.0 Release with Support for more Diagnostics, SQL/JSON, Oracle Associative Arrays, Multi dimensional Arrays, R2DBC 1.0
How to use jOOQ’s Converters with UNION Operations
jOOQ 3.15 introduced the concept of an ad-hoc converter, a converter that is applied "ad-hoc" to a single query. It uses the same underlying mechanisms as any ordinary Converter that is attached to generated code for use in every query. An example of such an ad-hoc converter is this: // Without the converter, assuming BOOK.ID … Continue reading How to use jOOQ’s Converters with UNION Operations
How to Write a Derived Table in jOOQ
One of the more frequent questions about jOOQ is how to write a derived table (or a CTE). The jOOQ manual shows a simple example of a derived table: In SQL: SELECT nested.* FROM ( SELECT AUTHOR_ID, count(*) books FROM BOOK GROUP BY AUTHOR_ID ) nested ORDER BY nested.books DESC In jOOQ: // Declare the … Continue reading How to Write a Derived Table in jOOQ
The Performance Impact of SQL’s FILTER Clause
I've found an interesting question on Twitter, recently. Is there any performance impact of using FILTER in SQL (PostgreSQL, specifically), or is it just syntax sugar for a CASE expression in an aggregate function? https://twitter.com/Ivan73965858/status/1622487080088600576 As a quick reminder, FILTER is an awesome standard SQL extension to filter out values before aggregating them in SQL. … Continue reading The Performance Impact of SQL’s FILTER Clause
Emulating Window Functions in MySQL 5.7
One of MySQL 8's biggest improvements is the support of window functions. As I always said in conferences, there's SQL before window functions and SQL after window functions. Once you start using them, you'll use them everywhere. Some of you poor souls are unfortunate enough to be stuck on MySQL 5.7, either of your own … Continue reading Emulating Window Functions in MySQL 5.7
Why You Should Execute jOOQ Queries With jOOQ
Previously on this blog, I've written a post explaining why you should use jOOQ's code generator, despite the possibility of using jOOQ without it. In a similar fashion, as I've answered numerous jOOQ questions on Stack Overflow, where someone used jOOQ to build a query, but then executed it elsewhere, including on: JPA JDBC / … Continue reading Why You Should Execute jOOQ Queries With jOOQ
jOOQ’s R2DBC LoggingConnection to log all SQL statements
jOOQ already has a LoggingConnection (see also the manual), which acts as a JDBC proxy Connection to log all SQL statements that are executed by any JDBC client (including Hibernate, MyBatis, JdbcTemplate, native JDBC, etc.). Starting from jOOQ 3.18.0, 3.17.7, and 3.16.13, a LoggingConnection is now also available for R2DBC clients to log all reactive … Continue reading jOOQ’s R2DBC LoggingConnection to log all SQL statements