Okie...I have this book on Proffessional PHP PRogramming and in the section of PHP & SQL Databases they have given this eg. with the CONSTRAINTS option....it goes like this. CREATE TABLE authorsofdoc ( docid INTEGER UNSIGNED NOT NULL, authorid INTEGER UNSIGNED NOT NULL, constraint pk_authorsofdoc PRIMARY KEY(docid, authorid) ) Now what the heck does the 4th line do? i have never seen a syntax like that in the CREATE TABLE syntax...wats all that 'constraint pk_authorsofdoc' and after that 'PRIMARY KEY()' option.... infact acording to CREATE TABLE syntax it should be... CONSTRAINT fk_authorsofdoc FOREIGN KEY(docid, authorid) isnt it??? or am i wrong? duke. "Cal Evans" <[EMAIL PROTECTED]> wrote: It's not implemented in MySQL. It's there for compatibility. In other flavors of SQL, constraints can be placed on relationships to enforce referential integrity. Cal http://www.calevans.com -----Original Message----- From: Duke [mailto:[EMAIL PROTECTED]] Sent: Monday, March 19, 2001 3:36 AM To: [EMAIL PROTECTED] Subject: What is CONSTRAINTS for? In the CREATE TABLE command there is a create_defn. option called ... CONSTRAINT symbol what is that for? and how does that work? duke. Website: http://www.ilug-bom.org.in/ Ftp site: ftp.ilug-bom.org.in Chat: irc.ilug-bom.org.in Linuxers mailing list: [EMAIL PROTECTED] http://ilug-bom.org.in/mailman/listinfo/linuxers ____________________________________________________________________ Get free email and a permanent address at http://www.netaddress.com/?N=1 --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php Website: http://www.ilug-bom.org.in/ Ftp site: ftp.ilug-bom.org.in Chat: irc.ilug-bom.org.in Linuxers mailing list: [EMAIL PROTECTED] http://ilug-bom.org.in/mailman/listinfo/linuxers ____________________________________________________________________ Get free email and a permanent address at http://www.netaddress.com/?N=1 --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
