Many days ago I made a database which had two tables:
member(member_id(PK),name)
account(account_id(PK),member_id(FK),amount).
So Normally I cant DELETE any member if member have balance in account table . Before it was work well.
But today I import same script and I can delete a member even member have balance in account table.
I don't know what happends? I don't remember previous server version of mysql. Now I am running mysql 5.5.16 and MySQL client version is mysqlnd 5.0.8-dev - 20102224 - Revision: 310735 in localhost.
my code is
//account table
CREATE TABLE IF NOT EXISTS `account` (
`account_id` int(11) NOT NULL AUTO_INCREMENT,
`member_id` int(11) NOT NULL,
`dates` date NOT NULL,
`amount` float NOT NULL,
PRIMARY KEY (`account_id`),
KEY `FK_account_1` (`member_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;
//member table
CREATE TABLE IF NOT EXISTS `member` (
`member_id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) NOT NULL,
`account_num` int(11) NOT NULL,
PRIMARY KEY (`member_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=34 ;
//and this code
ALTER TABLE `account`
ADD CONSTRAINT `FK_account_1`
FOREIGN KEY (`member_id`)
REFERENCES `member`(`member_id`)
ON DELETE CASCADE
ON UPDATE CASCADE;
I'm not sure if I understand this well but:
The constraint you have means that every time you delete a member, the member will be deleted together with any balance it has in the account table. (ON DELETE CASCADE)
If this is not your desired behavior, and you want mysql to raise an exception when deleting a member that has a balance; then just remove the ON DELETE CASCADE line from your constraint definition.
ALTER TABLE account
ADD CONSTRAINT `fk_account_member`
FOREIGN KEY (`member_id`)
REFERENCES `member` (`member_id`)
ON DELETE CASCADE
ON UPDATE CASCADE;
Related
I have two MySQL databases: master and slave. The master db contains the memberid field. How can I reference memberid in the slave db? This is what I've tried using the slave db with no success:
DROP TABLE IF EXISTS `attend_date_temp`;
CREATE TABLE `attend_date_temp` (
`clientid` int(10) unsigned NOT NULL,
`groupid` int(10) unsigned NOT NULL,
`memberid` int(10) unsigned NOT NULL,
KEY `clientid` (`clientid`),
KEY `memberid` (`memberid`),
CONSTRAINT `attend_date_temp_ibfk_1` FOREIGN KEY (`clientid`) REFERENCES `clients` (`clientid`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `attend_date_temp_ibfk_2` FOREIGN KEY (`memberid`) REFERENCES `master.members` (`memberid`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8
When I view the memberid foreign key in that table, I get this message:
Table 'slave.master.members' doesn't exist.
Can someone tell me what I'm doing wrong? This is the reference I used.
Thanks.
REFERENCES `master.members`
should be:
REFERENCES `master`.`members`
Otherwise, it tries to find a table called master.members in the slave database.
I have two tables -
CREATE TABLE `FOO` (
`user_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
/*Nothing to see here*/
PRIMARY KEY (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=380 DEFAULT CHARSET=latin1;
CREATE TABLE `BAR` (
`ID` int(11) unsigned NOT NULL,
`UserID` int(11) unsigned DEFAULT NULL,
PRIMARY KEY (`ID`),
KEY `VSK_UserID_Index` (`UserID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
I am attempting create a foreign key constraint on BAR.UserID referencing users.user_id -
ALTER TABLE `FOO`.`BAR`
ADD CONSTRAINT `BAR_UserID_FKey`
FOREIGN KEY (`UserID`)
REFERENCES `FOO`.`users` (`user_id`)
ON DELETE CASCADE
ON UPDATE CASCADE;
I keep getting this error -
Operation failed: There was an error while applying the SQL script to the database.
Error 1452: Cannot add or update a child row: a foreign key constraint fails
Both of these tables have data in them - could this be the reason why this is happening, or is there something wrong with how the tables are being created?
Is there something I need to alter on one of these tables to make this work?
The data already in one of the tables (in particular, `FOO`.`BAR`, since that is the one you're adding a constraint to) is not consistent with the data in `FOO`.`users` (`user_id`).
You must ensure that the values un the `FOO`.`BAR`.`UserID` column all exist in `FOO`.`users` (`user_id`). There may be null values or other values that do not exist in the other column.
Ok, so it's like this. I have 2 tables in phpmyadmin. One is for personal details and the other is for login information. Both tables have AccountID, so I tried using foreign key constraints to connect the tables. After I did that it seems like I cannot update the table with new data. Before the constraint, updating the tables worked fine.
What I'm trying to do is store user login info and personal info in these table. Then whenever the user wants to delete their current account, the personal details and login details of are deleted from both tables or when they wanted to search for their login and personal info the search engine can search from both tables with AccountID.
so far.i have make 2 new tables.1 table which is personal information have 'AccountID'[A_I][PRIMARY] and 'loginID'.another table is login info.it has 'loginID'[A_i][PRIMARY]
i already make the 'loginID' at personal info and index but i cannot assign foreign key constraint for it bcause it did not detect 'loginID' in personal info.
Your AccountId should be a primary key in one table say Personal Info table.
This AccountId should be the foreign key in another table (Login) and make sure you set on Delete Cascade and on Update Cascade.
So in this structure, when personal info is deleted, its corresponding record in the login table will be automatically deleted.
DROP TABLE IF EXISTS `stacktest`.`personal_info`;
CREATE TABLE `stacktest`.`personal_info` (
`account_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(45) DEFAULT NULL,
`age` varchar(45) DEFAULT NULL,
PRIMARY KEY (`account_id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;
DROP TABLE IF EXISTS `stacktest`.`login_info`;
CREATE TABLE `stacktest`.`login_info` (
`loginId` int(10) unsigned NOT NULL AUTO_INCREMENT,
`account_id` int(10) unsigned DEFAULT NULL,
PRIMARY KEY (`loginId`),
KEY `FK_login_info_1` (`account_id`),
CONSTRAINT `FK_login_info_1` FOREIGN KEY (`account_id`) REFERENCES `personal_info` (`account_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;
Above is the way how the 2 tables should be created.
Then insert some values in both table,
Note that account_id value has to be same in both the tables.
After that you can fire a delete query like:
delete from personal_info where accound_id=2;
This will delete rows from parent table personal_info and also from child table login_info where account_id is 2
Keeping the account_id as NOT NULL in child table:
DROP TABLE IF EXISTS `stacktest`.`login_info`;
CREATE TABLE `stacktest`.`login_info` (
`loginId` int(10) unsigned NOT NULL AUTO_INCREMENT,
`account_id` int(10) unsigned NOT NULL,
PRIMARY KEY (`loginId`),
KEY `FK_login_info_1` (`account_id`),
CONSTRAINT `FK_login_info_1` FOREIGN KEY (`account_id`) REFERENCES `personal_info` (`account_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;
I'm using MySQL version 5.5.25 and trying to create a foreign key from id_parent to id on the same table.
CREATE TABLE `acl_roles` (
`id` int(20) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(60) NOT NULL,
`id_parent` int(20) unsigned DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `FK_acl_roles` (`id_parent`),
CONSTRAINT `FK_acl_roles` FOREIGN KEY (`id_parent`) REFERENCES `acl_roles` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8
When I do
ALTER TABLE `acl_roles` ADD CONSTRAINT `FK_acl_roles` FOREIGN KEY (`id_parent`) REFERENCES `acl_roles` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT ;
For some reason the latter executes without error yet when I execute SHOW CREATE TABLE acl_roles I get the exact same schema and the restrictions are not applied no matter how many times I run the query.
ON DELETE RESTRICT ON UPDATE RESTRICT is the default behavior for FK constraints, that is why you see no difference when viewing the schema. It is implied.
I remember in my work in past projects I have ran across a MySQL error message that stated that no records can be the same ( all columns ) because then they cannot be individually selected. Unfortunately my MySQL doesn't give me this error and I have a problem.
I have a table to store a user's favorite topics ( or articles if you will ) which is fairly simple
CREATE TABLE `ad_favorites` (
`ad_id` int(10) unsigned NOT NULL,
`user_id` int(10) unsigned NOT NULL,
KEY `ad_id` (`ad_id`),
KEY `user_id` (`user_id`),
CONSTRAINT `ad_favorites_ibfk_1` FOREIGN KEY (`ad_id`) REFERENCES `ad` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `ad_favorites_ibfk_2` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8
I need to not be able to insert two same records and get an error in case there is such an attempt so that in my php my affected_rows property will show 0.
Long story short if I have a record and I try to insert it again I must get a MySQL error, is it possible?
make the two columns a composite primary key,
PRIMARY KEY (ad_id, user_id)