GraalVM is a universal virtual machine for running applications written in JavaScript, Python, Ruby, R, JVM-based languages like Java, Scala, Kotli n, Clojure, and LLVM-based languages such as C and C++.GraalVM removes the isolation between programming languages and enables interoperability in a shared runtime. It can run either standalone or in the context of …
Ring – Cache interface as a programming language integrationRing provides function-oriented cache interface for various backends. Repository: https://github.com/youknowone/ring/ Source: Ring – Cache interface as a programming language integration — Ring 0.7.2 documentation
WebAssembly (often shortened to Wasm) is a standard that defines a binary format and a corresponding assembly-like text format for executables used by web pages. [….] WebAssembly code is intended to be run on a portable abstract structured stack machine,[27] which is designed to be faster to parse than JavaScript, as well as faster to execute,[21] and to enable very compact code representation.In …
In the 1980 comments were used to reduce the “gap” between unstructured code and “rationale” behind the code. C/64 Peek and poke where oscure. Gosub on function pointed by numbers was bad 8-bit systems was tight on command names and so on (think to write a python interpreter in Arduino/bbc:Micro, or look at the memory …
I admit it. I suffered from an “algebra narcoleptic syndrome” during my relational database lessons at University (1996 circa). Ok it is a fake. But it seems so real on these days. I was unable to avoid sleeping. I learned to love SQL after some years and now I think SQL is the most powerful, …
SQL: One of the most valuable skills – Craig Kerstiens Read More »
For a complete description see https://www.codeproject.com/Articles/33052/Visual-Representation-of-SQL-Joins
It aims to provide a minimal compatibility with Oracle. The need was having some regular expression functions, and I do not like to work with risky C code, like this university project did
Qualche mese fa avevo sviluppato una applicazione IoT per misurare la temperatura e spedire i dati ad una coda mqtt. Poi c’era uns server che colelzzionava i dati. Totale: tre server, con tre punti di fallimento ma architettura molto “cool” In effetti però la potenza dei moderni chip embedded è tale che è possibile implementare …
Sometimes you need to remove nasty duplicate on a table, based on a subset of the column. Oracle trick:
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DELETE FROM your_table WHERE rowid not in (SELECT MIN(rowid) FROM your_table GROUP BY column1, column2, column3); |
Postgresql equivalent is ctid, so you can try something like
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delete from mytable where exists (select 1 from mytable t2 where t2.name = mytable.name and t2.address = mytable.address and t2.zip = mytable.zip and t2.ctid > mytable.ctid ); |
SQLite demo:
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create table dup_table (column1 text, column2 text, column3 text); insert into dup_table values('1','2','3'); insert into dup_table values('1','2','3'); insert into dup_table values('1','3','3'); DELETE FROM dup_table WHERE rowid not in (SELECT MIN(rowid) FROM dup_table GROUP BY column1, column2); select count(*) from dup_table; |
Also take a look at this old post on postgresql mailing list, if you incur in an older PostgreSQL version …
Removing duplicate rows in PostgreSQL, Oracle and SQLite Read More »
In Italian language we have accent words like àèéìòù They are quite important because for instance “is” is spelled è whereas “and” is spelled e Accent are bad guys even today: if you copy them from MS-Word inside an Oracle sql script you can end up with different UTF-8 values. Also the accent are likely …
