Easiest way to do this is to add a UNIQUE index on the column. When you write the ALTER statement, include the IGNORE keyword. Like so: ALTER IGNORE TABLE jobs ADD UNIQUE INDEX idx_name (site_id, title, company); This will drop all the duplicate rows. As an added benefit, future INSERTs that are duplicates will error … Read more
NDBCLUSTER (also known as NDB) is an in-memory storage engine offering high-availability and data persistence features. The NDBCLUSTER storage engine can be configured with a range of failover and load-balancing options, but it is easiest to start with the storage engine at the cluster level. MySQL Cluster’s NDB storage engine contains a complete set of … Read more
MySQL Cluster is a technology that enables clustering of in-memory databases in a shared-nothing system. The shared-nothing architecture enables the system to work with very inexpensive hardware, and with a minimum of specific requirements for hardware or software. MySQL Cluster is designed not to have any single point of failure. In a shared-nothing system, each … Read more
One means of restricting client use of MySQL server resources is to set the global max_user_connections system variable to a nonzero value. This limits the number of simultaneous connections that can be made by any given account, but places no limits on what a client can do once connected. In addition, setting max_user_connections does not … Read more
MySQL stores accounts in the user table of the mysql system database. An account is defined in terms of a user name and the client host or hosts from which the user can connect to the server. The account may also have a password. There are several distinctions between the way user names and passwords … Read more
Applications that access MySQL should not trust any data entered by users, who can try to trick your code by entering special or escaped character sequences in Web forms, URLs, or whatever application you have built. Be sure that your application remains secure if a user enters something like “; DROP DATABASE mysql;”. This is … Read more
This article describes general security issues to be aware of and what you can do to make your MySQL installation more secure against attack or misuse. Anyone using MySQL on a computer connected to the Internet should read this section to avoid the most common security mistakes. In discussing security, it is necessary to consider fully … Read more
The LOAD DATA statement can load a file that is located on the server host, or it can load a file that is located on the client host when the LOCAL keyword is specified. There are two potential security issues with supporting the LOCAL version of LOAD DATA statements: The transfer of the file from … Read more
Here is an example to select multiple column of a table from select statement in asterisk. exten => h,1,MYSQL(Connect conn localhost username password database) exten => h,n,MYSQL(Query res ${conn} ‘SELECT call_id,callerid,calltime FROM todaycall WHERE calltime=curdate() order by calltime desc limit 1′) exten => h,n,MYSQL(Fetch fid ${r} call_id callerid calltime) exten => h,n,MYSQL(Clear ${r}) exten => … Read more
Once replication has been started it should execute without requiring much regular administration. Depending on your replication environment, you will want to check the replication status of each slave periodically, daily, or even more frequently. Checking Replication Status: The most common task when managing a replication process is to ensure that replication is taking place … Read more