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Re: [NOVICE] PostgreSQL eller MySQL?



Björn Lundin wrote:
Frank Damgaard wrote:


men det nytter jo ikke hvis man har en applikation skal bruge
SQL-kommandoer/funktioner som kun leveres af PostgreSQL.


Det finns knappt några sådana, medans det finns ett otal MySql-special.
PostgreSQL ligger _betydligt_ nämre sqlstandarder än MySql.

PostgreSQL er udviklet af de samme folk, som oprindelig startede Ingres-projectet, så det er vel rimeligt at forvente, at PostgreSQL følger sqlstandarden, og dermed indeholder de funktioner, som er nødvendige for at kunne kaldes en "rigtig" database. Uden i detailler at kende forskellen på PostgreSQL og MySQL er det mit indtryk, at MySql har sine begrænsninger. Ingres blev på et tidspunkt kommercialiseret, hvorefter grundlæggeren af Ingres startede et Post-Ingres project. Se her:
http://www.zdnet.co.uk/talkback/?PROCESS=show&ID=20031087&AT=39173013-39020384t-10000007c
Citat:
"
Yes, you are correct. The name Postgres is a contraction of the term Post-Ingres and was a project started at UC Berkley by Dr. Michael Stonebraker, one of the founders of the Ingres project which also began life at UC Berkley.
There is no code shared between the two projects, but many of the ideas are similar.
"
Selvom jeg som sagt ikke kender så meget til forskellene mellem de nævnte databaser, tror jeg dog godt at kunne slå ned på en ikke uvæsentlig mangel i MySQL: begrebet rules.
Fra 'Ingres SQL Reference Guide'
"
A rule invokes a specified database procedure when it detects specified changes to the database. Rules can be fired by:
Any insert, update, or delete on a specified table (including a cursor update or delete).
An update that changes one or more columns in a table.
A change that results in a specified condition (expressed as aqualification).
"
PostgreSQL har også rules, som dog måske er implementeret på en lidt ansen måde. Se her:
http://www.postgresql.org/docs/7.3/static/rules.html#RULES-INTRO
Chapter 13. The Rule System.


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