Java EE ships with its own persistence API: JPA. JPA is most powerful when you want to map your RDBMS entities (tables / relations) to Java entities (classes), mostly following a 1:1 mapping strategy. The idea behind this is that often, business logic isn't really set-oriented as relational algebra or SQL, but record-oriented, meaning that … Continue reading A Beginner’s Guide to Using Java EE with jOOQ
Tag: sql
How to Quickly Enumerate Indexes in Oracle 11gR2
Do you want to know real quick what kind of indexes there are on any given table in your Oracle schema? Nothing simpler than that. Just run the following query: SELECT i.index_name, listagg(c.column_name, ', ') WITHIN GROUP (ORDER BY c.column_position) AS columns FROM all_indexes i JOIN all_ind_columns c ON i.index_name = c.index_name WHERE i.table_name = … Continue reading How to Quickly Enumerate Indexes in Oracle 11gR2
You Probably don’t Use SQL INTERSECT or EXCEPT Often Enough
When people talk about SQL JOIN, they often use Venn Diagrams to illustrate inclusion and exclusion of the two joined sets: While these Venn diagrams are certainly useful to understand (and remember) SQL JOIN syntax, they're not entirely accurate, because SQL JOIN is a special type of a cartesian product, the CROSS JOIN. In a … Continue reading You Probably don’t Use SQL INTERSECT or EXCEPT Often Enough
Let’s Meet at JAX London and Other Events to Talk About SQL
Exciting times are ahead for Java/SQL developers. SQL is strong and popular as ever. It is the right language for relational databases just as much as for Big Data storage systems. Just this week, Pivotal has announced their open sourcing HAWQ and MADlib as a part of their Hadoop Native SQL strategy. At Data Geekery, … Continue reading Let’s Meet at JAX London and Other Events to Talk About SQL
It is all about the JDBC Basics
We're very happy to announce a guest post by Marco Behler, who has been blogging about jOOQ in the past. Marco started out in programming (reverse-engineering, actually) and now mainly programmes on the JVM in his day-to-day work. He also always had a sweet tooth for strategy and marketing. Marco Behler GmbH is the result … Continue reading It is all about the JDBC Basics
Don’t Format Dates in SQL. Use the DATE Literal!
I'm seeing people do this all the time. They want to hammer a date or timestamp constant into their SQL query, and the only function they know is the TO_DATE() or TO_TIMESTAMP() date parsing function: SELECT TO_DATE ('20150801', 'yyyymmdd') FROM DUAL; As observed in this Stack Overflow question, for instance: TO_DATE ('20150801', 'yyyymmdd') AS DAY_20150801_TOTAL, … Continue reading Don’t Format Dates in SQL. Use the DATE Literal!
There is no Such Thing as Object-Relational Impedance Mismatch
Much of the ORM criticism of the last decade missed the point, being inaccurate. By the end of this article, we will conclude with the following: There is no significant difference between the relational (data) model and object oriented models How to come to this conclusion? Read on! How we came to believe in this … Continue reading There is no Such Thing as Object-Relational Impedance Mismatch
jOOQ Tuesdays: Thomas Müller Unveils How HSQLDB Evolved into the Popular H2 Database
Welcome to the jOOQ Tuesdays series. In this series, we’ll publish an article on the third Tuesday every other month where we interview someone we find exciting in our industry from a jOOQ perspective. This includes people who work with SQL, Java, Open Source, and a variety of other related topics. We have the pleasure … Continue reading jOOQ Tuesdays: Thomas Müller Unveils How HSQLDB Evolved into the Popular H2 Database
Common SQL Clauses and Their Equivalents in Java 8 Streams
Functional programming allows for quasi-declarative programming in a general purpose language. By using powerful fluent APIs like Java 8's Stream API, or jOOλ's sequential Stream extension Seq or more sophisticated libraries like vavr or functionaljava, we can express data transformation algorithms in an extremely concise way. Compare Mario Fusco's imperative and functional version of the … Continue reading Common SQL Clauses and Their Equivalents in Java 8 Streams
RAM is the new SSD
Your data fits in RAM. Yes, it does. Don't believe it? Visit the hilarious yourdatafitsinram.com website. But there is an entirely new dimension to this since last week's announcement by Intel, which hasn't gotten enough attention in the blogosphere yet. New 3D XPoint™ technology brings non-volatile memory speeds up to 1,000 times faster than NAND, … Continue reading RAM is the new SSD