Hi there,

I would like to create a table that optionally links to an other table.

The field company_id in the following table should be either Null or link to the
table tblCompany (`id` ).
How do I do that. The way I it now, I can not enter records where the field
company_id is null.

Thanks
robert

drop table IF EXISTS tblAgentCompanyMapper;
CREATE TABLE IF NOT EXISTS `energie_2`.`tblAgentCompanyMapper` (
`siaid` INT COMMENT 'id assigned in the excelsheet by SIA' ,
`company_id` INT NULL DEFAULT NULL UNIQUE COMMENT 'id automatically used by
energiecluster adresses' ,
`name` VARCHAR(128) NOT NULL ,
`url` VARCHAR(256) NULL ,
INDEX `fk_tblAgentCompanyMapper_tblCompany1` (`company_id` ASC) ,
PRIMARY KEY (`siaid`) ,
CONSTRAINT `fk_tblAgentCompanyMapper_tblCompany1`
FOREIGN KEY (`company_id` )
REFERENCES `energie_2`.`tblCompany` (`id` )
ON DELETE SET NULL
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;


--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql?unsub=listsearcharchive@lassosoft.com