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
Oracle trick: [sql] DELETE FROM your_table WHERE rowid not in (SELECT MIN(rowid) FROM your_table GROUP BY column1, column2, column3); [/sql] Postgresql equivalent is ctid, so you can try something like [sql] 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 …
Removing duplicate rows in PostgreSQL and Oracle Read More »
On some environment, on some customers, Oracle connections are drop after some idle time (i.e. 2 minutes). I have found a small plugin for Sql Developer to solve this issue: it is very handy and logs its usage. Code is also very clean keepalive extension for Oracle SQL Developer 4+https://github.com/scristalli/SQL-Developer-4-keepalive9 forks.84 stars.6 open issues.Recent commits: Fix …
Okey, you know Oracle. A very good database, a very old database, a very solid rock. Not famous for its error messages. I have already stumbled upon a misleading error on the old rock. This error anyway is incredible. If you try to push a very long text in a varchar2, you can end up with …
ORA-01461: can bind a LONG value only for insert into a LONG column Read More »
I stumbled upon a very brain-f**k error on Oracle 10g on these days. Context: the following query [sql]SELECT * FROM ( SELECT TO_NUMBER(CUSTOMER_ID) AS SNDG FROM BAD_CODES_TABLE WHERE AND I_LIKE=UPPER(‘STATIC_CONDITION’) AND CUSTOMER_ID NOT LIKE ‘%P%’ ) S WHERE TO_NUMBER(S.SNDG) >2000[/sql] could trigger a Invalid number if CUSTOMER_ID column contains invalid numbers. Why? Well…if you ask …
Come evitare iniezione SQL: lato SQL Server (SP_EXECUTESQL) In generale va evitato nel modo più assoluto la scrittura di query sql diamiche. Va evitato cioè l’uso lato SQL Server di sp_executesql e EXEC Di seguito mostriamo come trasformare una query “dinamica” in una “statica” [sql]CREATE PROCEDURE search_orders @custid nchar(5) = NULL, @shipname nvarchar(40) = …
Come evitare iniezioni SQL lato DB in SQLServer, Oracle, MySQL Read More »
Dapper is a single file you can drop in to your project that will extend your IDbConnection interface. […] A key feature of Dapper is performance. The following metrics show how long it takes to execute 500 SELECT statements against a DB and map the data returned to objects. The performance tests are broken …
dapper-dot-net – Simple SQL object mapper for SQL Server – Google Project Hosting Read More »
At Gioorgi.com we was never a SQL fan. In 2000 we thinked SQL was boring, mostly because sql algebra could be a bit boring. Then we found this book written by one of the father of SQL. Years ago Google and then Facebook popped out with new incredible ideas, for improved and super fast scalability, which eventually …
