I could be wrong but I think your problem is the unique index. -- João Cândido de Souza Neto
"robert rottermann" <rob...@redcor.ch> escreveu na mensagem news:4dd967a8.5040...@redcor.ch... > 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=arch...@jab.org
