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 did, didn't agree on syntax. But this is about to change. Thanks to the now ubiquitous SQL/JSON support (which jOOQ … Continue reading jOOQ 3.15’s New Multiset Operator Will Change How You Think About SQL
Tag: Oracle
Use IN List Padding to Your JDBC Application to Avoid Cursor Cache Contention Problems
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 described in lengths in previous articles, can be summarised as this. All of these are distinct SQL queries and need to be parsed … Continue reading Use IN List Padding to Your JDBC Application to Avoid Cursor Cache Contention Problems
Automatically 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 features: Its parser. Having been introduced in jOOQ 3.9 primarly for the purpose of being able to parse DDL … Continue reading Automatically Transform Oracle Style Implicit Joins to ANSI JOIN using jOOQ
Having “constant” columns in foreign keys
I was asked a very interesting question on Twitter just now: https://twitter.com/connolly_s/status/1303957373107818497 Can we have "constant" foreign key columns in (PostgreSQL) tables? Luckily, yes, we can. Using a nice standard feature that is "computed columns" or "generated columns" Sometimes, you cannot completely normalise your schema for whatever reason. There may be a case where you … Continue reading Having “constant” columns in foreign keys
Using 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 than the standard SQL/XML or SQL/JSON APIs - although the standard ones are more powerful. In this blog post, I'd like to show a few … Continue reading Using SQL Server FOR XML and FOR JSON Syntax on Other RDBMS With jOOQ
What’s Faster? COUNT(*) or COUNT(1)?
One of the biggest and undead myths in SQL is that COUNT(*) is faster than COUNT(1). Or was it that COUNT(1) is faster than COUNT(*)? Impossible to remember, because there's really no reason at all why one should be faster than the other. But is the myth justified? Let's measure! How does COUNT(...) work? But … Continue reading What’s Faster? COUNT(*) or COUNT(1)?
Oracle’s BINARY_DOUBLE Can Be Much Faster Than NUMBER
Using the right data type for some calculation sounds like some obvious advice. There are many blogs about using temporal data types for temporal data, instead of strings. An obvious reason is data integrity and correctness. We don't gain much in storing dates as 2019-09-10 in one record, and as Nov 10, 2019 in the … Continue reading Oracle’s BINARY_DOUBLE Can Be Much Faster Than NUMBER
How to Fetch All Current Identity Values in Oracle
Oracle 12c has introduced the useful SQL standard IDENTITY feature, which is essentially just syntax sugar for binding a sequence to a column default. We can use it like this: create table t1 (col1 number generated always as identity); create table t2 (col2 number generated always as identity); insert into t1 values (default); insert into … Continue reading How to Fetch All Current Identity Values in Oracle
Using IGNORE NULLS With SQL Window Functions to Fill Gaps
I found a very interesting SQL question on Twitter recently: https://twitter.com/vikkiarul/status/1120669222672261120 Rephrasing the question: We have a set of sparse data points: +------------+-------+ | VALUE_DATE | VALUE | +------------+-------+ | 2019-01-01 | 100 | | 2019-01-02 | 120 | | 2019-01-05 | 125 | | 2019-01-06 | 128 | | 2019-01-10 | 130 | +------------+-------+ … Continue reading Using IGNORE NULLS With SQL Window Functions to Fill Gaps
Calling an Oracle Function with PL/SQL BOOLEAN Type from SQL
One of the most wanted features in the Oracle database is the BOOLEAN type. The SQL standard specified it a while ago, and RDBMS like PostgreSQL show how powerful it can be, e.g. when using the EVERY() aggregate function. Before you move on reading this article, note that starting with Oracle 23c, the standard BOOLEAN … Continue reading Calling an Oracle Function with PL/SQL BOOLEAN Type from SQL