What does unsigned in mysql mean?

What does MySQL error number 10060 mean?

• Answer:

  There is, in fact, no MySQL error with that number. The actual error number is at the beginning of the message (i.e.: ERROR 2003: Can't connect to MySQL server (10060)"). Typically though, when you see that number it is related to an authentication issue of some sort. Either you are trying to authenticate (log in) from an IP address/host that isn't authorized to or there is a problem related to the MySQL server's TCP/IP bindings. There are four common reasons why you would get an error message like this: 1) The MySQL server isn't running. 2) MySQL's configuration file specifies that it is only listening on a certain IP:Port and that you're not communicating through the specified address (i.e.: Your MySQL server's system has multiple NICs and you are communicating with the server through the NIC not specified). 3) You have the MySQL server is being started with the --skip-networking option enabled either from the startup script or in the .conf file. 4) The user name being used to authenticate to the MySQL server is not allowed to connect from the client computer's IP address/host (i.e.: User "Alice" is only allowed to log in from 192.168.0.100 but is trying to log in from 192.168.0.200). Link: http://dev.mysql.com/doc/refman/5.1/en/can-not-connect-to-server.html