Understanding MySQL transactions

Kouber Saparev on December 3 2010 11:01am at MySQL page (http://dev.mysql.com/doc/refman/5.5/en/innodb-locking-reads.html) says: Keep in mind that MySQL transactions are not fully atomic in the sense of the “all or nothing” rule. You can commit a transaction with half of the statements done, and the other half failed. Test case: mysql> create table t7 (id integer … Read moreUnderstanding MySQL transactions

What does var mean in c#

Source: http://stackoverflow.com/questions/4307467/what-does-var-mean-in-c It means that the type of the local being declared will be inferred by the compiler: // This statement: var foo = “bar”; // Is equivalent to this statement: string foo = “bar”; Notably, var does not define a variable to be of a dynamic type. So this is NOT legal: var foo = “bar”; foo … Read moreWhat does var mean in c#

Use of GetElementsByTagName considered harmful

Source: http://blogs.msdn.com/b/eriksalt/archive/2005/07/20/getelementsbytagname.aspx As you may already be aware, there is an article on msdn about the great performance improvements we made in the V2 xml stack.  This is a pretty big event for the team, since increasing performance was one of the big goals of this release. While I posted this to give a shout-out to the team for … Read moreUse of GetElementsByTagName considered harmful

Understanding Innodb transaction Isolation

Source: http://ronaldbradford.com/blog/understanding-mysql-innodb-transaction-isolation-2009-09-24/ The MySQL Innodb storage engine provides ACID compliance, the ‘I’ being isolation. There are four states defined in MySQL with thetx_isolation system variable, READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ and SERIALIZABLE. Generally MySQL installations do not modify the default value of tx_isolation = REPEATABLE-READ, however I have seen with a number of clients the default value has been changed to READ-COMMITTED. When … Read moreUnderstanding Innodb transaction Isolation

MySQL useful commands

Some typical useful MySQL commands. The following statements were tested with MySQL version 5.1 and 5.5. Create database: mysql>CREATE SCHEMA IF NOT EXISTS `db_name` DEFAULT CHARACTER SET utf8 COLLATE utf8_bin; Create user: mysql> create user ‘user_id’@’localhost’ identified by ‘xxx’; Query OK, 0 rows affected (0.00 sec) Grant only select on db_name to user user_id@localhost. Ofcource … Read moreMySQL useful commands