Changeset 679
- Timestamp:
- 08/18/07 13:29:21 (1 year ago)
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materials/advocacy/trunk/Why_PostgreSQL_Instead_of_MySQL.txt
r678 r679 123 123 // version they were written against, and it may require a sort of porting effort to take advantage of the modern MySQL 124 124 // features. 125 Un autre sujet qui sort du cadre de ce document est qu'un nombre plus important d'applications choisissent MySQL comme 126 base de données plutôt que PostgreSQL, et ceci est certainement un facteur d'influence important sur le choix de la 127 base la plus adaptée à une situation particulière. Le travail pour ajouter un support PostgreSQL à plusieurs 128 applications populaires peut-être mené en adaptant les logiciels. Une chose que vous devez considérer lorsque vous 129 étudiez comment les applications utilisent MySQL est si elles sont initialement destinées aux versions antérieures à 130 5.0, elles pourraient alors ne plus être compatibles avec les nouvelles fonctionnalités comme le mode strict ajouté 131 dans cette version. Si cela est le cas, de telles applications pourraient être limitées aux capacités des plus vieilles 132 versions pour lesquelles elles ont été écrites et pourraient demander un effort d'adaptation pour profiter des 133 fonctionnalités modernes de MySQL. 134 125 135 // Reliability 136 Fiabilité 137 126 138 // Data Integrity 139 Intégrité des données 140 127 141 // Before version 5.0, MySQL well deserved its reputation for allowing inconsistent data to be inserted into the 128 142 // database. Guaranteeing Data Integrity with MySQL 5.0 explains the issues with older MySQL versions, and how they may … … 131 145 // necessarily enforced by the server. 132 146 133 PostgreSQL has always been strict about making sure data is valid before allowing it into the database, and there is no way for a client to bypass those checks. 134 Transactions and the Database Engine Core 147 // PostgreSQL has always been strict about making sure data is valid before allowing it into the database, and there is 148 // no way for a client to bypass those checks. 149 150 // Transactions and the Database Engine Core 151 135 152 The database core that gave MySQL its original reputation for speed is MyISAM. This engine has excellent read performance and its parser is very efficient for straightforward queries, which combine to make it very fast in read-intensive applications like web applications involving simple SELECTs. However, it is commonly known that MyISAM is more vulnerable to data corruption than most serious database applications would tolerate, and after a crash there may be a substantial delay while it rebuilds its indexes before the server can restart. Furthermore, it does not support foreign keys or transactions that would allow the database to have ACID properties. MyISAM also has issues dealing with concurrent reads and updates, since it only provides table level locking. 136 153
