VbzCart/tables/user client

About

 * Status: working / tested / debugged
 * Fields
 * CRC: checksum uniquely identifying user's IP address and browser client software. See notes.
 * Notes:
 * For identifying the user, decided to use CRC32 instead of compression because the compressed strings always came out at least as long as the original string. They were probably designed to be effective for rather longer data.
 * History:
 * 2009-06-16 Changing name to singular
 * 2009-09-11 CRC comes out negative sometimes, so making this SIGNED
 * 2013-11-09 Renamed from shop_client to user_client

SQL
DROP TABLE IF EXISTS `user_client`; CREATE TABLE `shop_client` ( `ID`         INT         NOT NULL AUTO_INCREMENT,  `CRC`        INT         NOT NULL COMMENT "crc32(Address+Browser) - unique integer defined by client specs",  `Address`    VARCHAR(15) NOT NULL COMMENT "IP address of client",  `Domain`     VARCHAR(255)         COMMENT "Domain name of client",  `Browser`    VARCHAR(255)         COMMENT "Browser USER_AGENT string",  `WhenFirst`  DATETIME    NOT NULL COMMENT "When this client was first seen",  `WhenFinal`  DATETIME             COMMENT "When this client was most recently seen",  PRIMARY KEY(`ID`),  UNIQUE KEY(`CRC`) ) ENGINE = MYISAM;