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I am starting to learn how databases work and I have always had all my data in one table. I am looking over an open-source project which I would like to create an interface for and the database structure is too complicated for me to understand.
I am sure it has a relational database structure (if I have learned properly). This is what the database structure looks like:
-- Table structure for table `databasechangelog`
--
CREATE TABLE IF NOT EXISTS `databasechangelog` (
`ID` varchar(255) NOT NULL,
`AUTHOR` varchar(255) NOT NULL,
`FILENAME` varchar(255) NOT NULL,
`DATEEXECUTED` datetime NOT NULL,
`ORDEREXECUTED` int(11) NOT NULL,
`EXECTYPE` varchar(10) NOT NULL,
`MD5SUM` varchar(35) DEFAULT NULL,
`DESCRIPTION` varchar(255) DEFAULT NULL,
`COMMENTS` varchar(255) DEFAULT NULL,
`TAG` varchar(255) DEFAULT NULL,
`LIQUIBASE` varchar(20) DEFAULT NULL,
`CONTEXTS` varchar(255) DEFAULT NULL,
`LABELS` varchar(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
-- --------------------------------------------------------
-- Table structure for table `databasechangeloglock`
--
CREATE TABLE IF NOT EXISTS `databasechangeloglock` (
`ID` int(11) NOT NULL,
`LOCKED` bit(1) NOT NULL,
`LOCKGRANTED` datetime DEFAULT NULL,
`LOCKEDBY` varchar(255) DEFAULT NULL,
PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
-- --------------------------------------------------------
-- Table structure for table `devices`
--
CREATE TABLE IF NOT EXISTS `devices` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(128) NOT NULL,
`uniqueid` varchar(128) NOT NULL,
`status` varchar(128) DEFAULT NULL,
`lastupdate` timestamp NULL DEFAULT NULL,
`positionid` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `uk_device_uniqueid` (`uniqueid`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;
-- --------------------------------------------------------
-- Table structure for table `positions`
--
CREATE TABLE IF NOT EXISTS `positions` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`protocol` varchar(128) DEFAULT NULL,
`deviceid` int(11) NOT NULL,
`servertime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`devicetime` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`fixtime` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`valid` bit(1) NOT NULL,
`latitude` double NOT NULL,
`longitude` double NOT NULL,
`altitude` float NOT NULL,
`speed` float NOT NULL,
`course` float NOT NULL,
`address` varchar(512) DEFAULT NULL,
`attributes` varchar(4096) NOT NULL,
PRIMARY KEY (`id`),
KEY `position_deviceid_fixtime` (`deviceid`,`fixtime`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=145 ;
-- --------------------------------------------------------
-- Table structure for table `server`
--
CREATE TABLE IF NOT EXISTS `server` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`registration` bit(1) NOT NULL DEFAULT b'1',
`latitude` double NOT NULL DEFAULT '0',
`longitude` double NOT NULL DEFAULT '0',
`zoom` int(11) NOT NULL DEFAULT '0',
`map` varchar(128) DEFAULT NULL,
`language` varchar(128) DEFAULT NULL,
`distanceunit` varchar(128) DEFAULT NULL,
`speedunit` varchar(128) DEFAULT NULL,
`bingkey` varchar(128) DEFAULT NULL,
`mapurl` varchar(128) DEFAULT NULL,
`readonly` bit(1) NOT NULL DEFAULT b'0',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;
-- --------------------------------------------------------
-- Table structure for table `users`
--
CREATE TABLE IF NOT EXISTS `users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(128) NOT NULL,
`email` varchar(128) NOT NULL,
`hashedpassword` varchar(128) NOT NULL,
`salt` varchar(128) NOT NULL,
`readonly` bit(1) NOT NULL DEFAULT b'0',
`admin` bit(1) NOT NULL DEFAULT b'0',
`map` varchar(128) NOT NULL DEFAULT 'osm',
`language` varchar(128) NOT NULL DEFAULT 'en',
`distanceunit` varchar(128) NOT NULL DEFAULT 'km',
`speedunit` varchar(128) NOT NULL DEFAULT 'kmh',
`latitude` double NOT NULL DEFAULT '0',
`longitude` double NOT NULL DEFAULT '0',
`zoom` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`id`),
UNIQUE KEY `uk_user_email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;
-- --------------------------------------------------------
-- Table structure for table `user_device`
--
CREATE TABLE IF NOT EXISTS `user_device` (
`userid` int(11) NOT NULL,
`deviceid` int(11) NOT NULL,
KEY `fk_user_device_deviceid` (`deviceid`),
KEY `user_device_user_id` (`userid`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
--
-- Constraints for dumped tables
--
--
-- Constraints for table `positions`
--
ALTER TABLE `positions`
ADD CONSTRAINT `fk_position_deviceid` FOREIGN KEY (`deviceid`) REFERENCES `devices` (`id`) ON DELETE CASCADE;
--
-- Constraints for table `user_device`
--
ALTER TABLE `user_device`
ADD CONSTRAINT `fk_user_device_deviceid` FOREIGN KEY (`deviceid`) REFERENCES `devices` (`id`) ON DELETE CASCADE,
ADD CONSTRAINT `fk_user_device_userid` FOREIGN KEY (`userid`) REFERENCES `users` (`id`) ON DELETE CASCADE;
When a user registers, it adds an entry to the "users" table and the user gets an id.
Then when the user adds a device, the user_device table looks like this:
And the devices table looks like this:
This is a GPS tracking software, so each device then posts it's position in the "positions" table which looks like this:
So, if a user logs in, how do I query the positions table and get all info from all devices of that user? I am assuming I would need to join the tables but I don't know how to do that. Any help would be greatly appreciated.
Let's build it incrementally. First, what is the actual data you want?
query the positions table
Ok, start with that:
SELECT
*
FROM
positions
Now how do you want to further filter that data?
from all devices of that user
Ok, so we need to relate this table (positions) through devices and to the user. So ultimately we'll need a WHERE clause like this:
WHERE
userid = ?
But positions doesn't have a userid, so let's walk through joining some tables until we have one. positions does have a deviceid, so we can join that:
SELECT
*
FROM
positions
INNER JOIN devices
ON positions.deviceid = devices.id
We still don't have a userid, though. And devices itself doesn't reference anything to further help us. But there's a table which does reference devices, user_device. Let's join that:
SELECT
*
FROM
positions
INNER JOIN devices
ON positions.deviceid = devices.id
INNER JOIN user_device
ON devices.id = user_device.deviceid
You'll see that we're getting a lot of data now. But you'll also see that we're now getting a userid column, so we can finally add our WHERE clause:
SELECT
*
FROM
positions
INNER JOIN devices
ON positions.deviceid = devices.id
INNER JOIN user_device
ON devices.id = user_device.deviceid
WHERE
userid = ?
At this point we should be getting all of the unique positions from any device related to that user. You can get just the position data by replacing SELECT * with SELECT positions.*, or you can explicitly define which columns from which tables you want to select.
it would appear from your notes that you know when the user logs in which device he has. if this is correct, you should not need a join. Just do a select on the positions table where the positions.deviceid = the login device.
I have this table structure
CREATE TABLE IF NOT EXISTS `users` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`username` varchar(50) DEFAULT NULL,
`realname` varchar(50) NOT NULL,
`password` varchar(50) DEFAULT NULL,
`email` varchar(50) DEFAULT NULL,
`bos1` varchar(30) DEFAULT NULL,
`emailbos1` varchar(50) DEFAULT NULL,
`role` varchar(20) DEFAULT NULL,
`created` datetime DEFAULT NULL,
`modified` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=21 ;
I got an issue here :
Two persons (eg: username=steve, and balmer) has bos1 name (eg: bill)
When I login as steve and/or balmer I can see my own detail / data,
but when I login as bill, I want to show steve's and balmer's detail as well.
How do i suppose to do it ?
Thank you.
I have a table environments that has both a createdBy field, as well as an updatedBy field. These fields store a member ID.
There is also a table members which houses the ID and the username. Below are the queries to create the tables
CREATE TABLE `environments` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(45) DEFAULT NULL,
`createdBy` varchar(45) DEFAULT NULL,
`createdDtTm` datetime DEFAULT NULL,
`updatedBy` varchar(45) DEFAULT NULL,
`updatedDtTm` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8$$
CREATE TABLE `members` (
`member_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`firstname` varchar(100) DEFAULT NULL,
`lastname` varchar(100) DEFAULT NULL,
`login` varchar(100) NOT NULL DEFAULT '',
`passwd` varchar(32) NOT NULL DEFAULT '',
PRIMARY KEY (`member_id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8$$
I would like to write a query that displays all the environments, but instead of an ID showing, I'd the the user name to show. Since they can be different though, I'm not sure how to write the join statement. Ideas?
You need a double join. SOmething along the lines of
SELECT
environments.*,
creators.firstname AS cfirstname,
creators.lastname AS clastname,
updaters.firstname AS ufirstname,
updaters.lasstname AS ulastname
FROM
environments
INNER JOIN members AS creators ON environments.createdBy=creators.login
LEFT JOIN members AS updaters ON environments.updatedBy=updaters.login
WHERE -- whatever
I have been making a database and learning along the way. I recently got into using InnoDB and using foreign keys to connect tables together.
But in all honestly I'm probably making my foreign keys blindly. What is the correct set and check list that I need to use when making a foreign key.
My understanding with foreign keys is that I have a Master Table, and any changes in my Master Table are reflected to any tables that hold a foreign key to a specific column in it.
So my current log-in system has a set up like this
users
=====
id PK
username
password
and my other tables look like this
contacts
========
id PK
user_id references `users`.`id`
group
name
address
groups
======
id PK
user_id
group_name
group_contacts
==============
id PK
group_id references `group`.`id`
contact_id references `contacts`.`id`
To my understanding these tables can be deleted when the Master Table is deleted using the ON DELETE CASCADE option correct?
My problem now is that I can't seem to make group_id and contact_id a Foreign key to groups.id and contacts.id with this setup. I get an error when running the SQL statements.
I'm trying to make my address book so that when a user places a contact into a group becomes all automated and I don't have to change much information. The group_contact table is what I THINK I will querying when I want to see where each contact belongs to. If I change the name of a group it will reflect across all tables right? This is where foreign keys come in and I'm confusing myself with how these keys should behave for me.
But like I said I can't seem to make a foreign key without getting an error.
I know I can Google my Foreign Key question, which I have but I can't seem to learn this way without getting feedback and input to my exact scenario ;(
Not to ask too much but because of my confusion I'm also having a hard time trying to see how I can make a PHP script to handle the group name change and query the database to pull down contacts that belong to a specific group.
This would really help me a lot guys, and I hope to learn something!
My query is this:
ALTER TABLE `list_`.`groups_contacts`
ADD CONSTRAINT `group_id` FOREIGN KEY (`group_id`) REFERENCES `list_`.`groups` (`id`)
ADD CONSTRAINT `contact_id` FOREIGN KEY (`contact_id`) REFERENCES `list_`.`contacts` (`id`);
My database looks like this:
CREATE TABLE `list_`.`buyer` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` tinyint(11) NOT NULL,
`isClosed` tinyint(1) NOT NULL,
`display_limit` int(1),
`first_name` varchar(255) NOT NULL,
`last_name` varchar(255) NOT NULL,
`prop_address` varchar(255) NOT NULL,
`city` varchar(255) NOT NULL,
`state` varchar(11) NOT NULL,
`zip` varchar(5) NOT NULL,
`cell_phone` varchar(16) NOT NULL,
`home_phone` varchar(16) NOT NULL,
`other1` varchar(16) NOT NULL,
`other2` varchar(16) NOT NULL,
`comments` text NOT NULL,
`comment_exist` tinyint(1) NOT NULL,
`comment_date` text NOT NULL,
`date_added` date NOT NULL,
`date_modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`,`user_id`),
KEY `user_id` (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=23 DEFAULT CHARSET=utf8 AUTO_INCREMENT=23 ;
CREATE TABLE `list_`.`company` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` tinyint(11) NOT NULL DEFAULT '0',
`company_name` varchar(128) NOT NULL,
PRIMARY KEY (`id`, `user_id`),
KEY `user_id` (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 AUTO_INCREMENT=3 ;
CREATE TABLE `list_`.`contacts` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` tinyint(11) NOT NULL,
`group` varchar(128) NOT NULL,
`first_name` varchar(128) NOT NULL,
`last_name` varchar(128) NOT NULL,
`address` varchar(128) NOT NULL,
`city` varchar(128) NOT NULL,
`state` varchar(2) NOT NULL,
`zip` int(5) NOT NULL,
`phone_number` varchar(16) NOT NULL,
`cell_number` varchar(16) NOT NULL,
`work_number` varchar(16) NOT NULL,
`fax_number` varchar(16) NOT NULL,
`email` varchar(128) NOT NULL,
`company` varchar(55) NOT NULL,
`title` varchar(56) NOT NULL,
`notes` text NOT NULL,
`date_added` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`,`user_id`),
KEY `user_id` (`user_id`),
KEY `group` (`group`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8 AUTO_INCREMENT=9 ;
CREATE TABLE `list_`.`groups` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` tinyint(11) NOT NULL,
`position` int(8) unsigned NOT NULL DEFAULT '0',
`name` varchar(128) NOT NULL,
`date_added` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`,`user_id`),
KEY `user_id` (`user_id`),
KEY `name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=32 DEFAULT CHARSET=utf8 AUTO_INCREMENT=32 ;
CREATE TABLE `list_`.`prospect` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` tinyint(11) NOT NULL,
`isClosed` tinyint(1) DEFAULT '0',
`display_limit` int(1) DEFAULT '0',
`first_name` varchar(255) NOT NULL,
`last_name` varchar(255) NOT NULL,
`prop_address` varchar(255) NOT NULL,
`city` varchar(255) NOT NULL,
`state` varchar(11) NOT NULL,
`zip` varchar(5) NOT NULL,
`cell_phone` varchar(16) NOT NULL,
`home_phone` varchar(16) NOT NULL,
`other1` varchar(16) NOT NULL,
`other2` varchar(16) NOT NULL,
`comments` text NOT NULL,
`date_added` date NOT NULL,
`date_modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`,`user_id`),
KEY `user_id` (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8 AUTO_INCREMENT=7 ;
CREATE TABLE `list_`.`seller` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` tinyint(11) NOT NULL,
`file` int(11) DEFAULT NULL,
`isClosed` tinyint(1) NOT NULL,
`display_limit` int(1) NOT NULL DEFAULT '0',
`first_name` varchar(255) NOT NULL,
`last_name` varchar(255) NOT NULL,
`prop_address` varchar(255) NOT NULL,
`city` varchar(255) NOT NULL,
`state` varchar(22) NOT NULL,
`zip` varchar(5) NOT NULL,
`cell_phone` varchar(16) NOT NULL,
`home_phone` varchar(16) NOT NULL,
`other1` varchar(16) NOT NULL,
`other2` varchar(16) NOT NULL,
`comments` text NOT NULL,
`comment_exist` tinyint(1) NOT NULL,
`comment_date` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`date_added` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`date_modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`,`user_id`),
KEY `user_id` (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=utf8 AUTO_INCREMENT=21 ;
CREATE TABLE `list_`.`settings` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` tinyint(11) NOT NULL,
`seller_display_limit` int(4) DEFAULT '0',
`buyer_display_limit` int(4) DEFAULT '0',
`prospect_display_limit` int(4) DEFAULT '0',
`property_display_limit` int(4) DEFAULT '0',
`date_modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`,`user_id`),
KEY `user_id` (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;
CREATE TABLE `list_`.`users` (
`id` tinyint(11) NOT NULL AUTO_INCREMENT,
`md5_id` varchar(200) NOT NULL,
`username` varchar(255) NOT NULL,
`password` varchar(255) NOT NULL,
`user_level` tinyint(1) DEFAULT '1',
`first_name` varchar(200) NOT NULL,
`last_name` varchar(200) NOT NULL,
`email` varchar(200) DEFAULT NULL,
`approved` int(1) NOT NULL,
`banned` int(1) NOT NULL,
`date_joined` date NOT NULL,
`ip` varchar(15) DEFAULT NULL,
`activation_code` int(9) DEFAULT NULL,
`ckey` varchar(220) NOT NULL,
`ctime` varchar(220) NOT NULL,
`last_logged_in` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`account_number` varchar(128) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 AUTO_INCREMENT=4 ;
ALTER TABLE `list_`.`buyer`
ADD CONSTRAINT `buyer_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON UPDATE CASCADE;
--
-- Constraints for table `company`
--
ALTER TABLE `list_`.`company`
ADD CONSTRAINT `company_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON UPDATE CASCADE;
--
-- Constraints for table `contacts`
--
ALTER TABLE `list_`.`contacts`
ADD CONSTRAINT `contacts_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`),
ADD CONSTRAINT `group_ibfk_2` FOREIGN KEY (`group`) REFERENCES `groups` (`name`) ON UPDATE CASCADE;
--
-- Constraints for table `groups`
--
ALTER TABLE `list_`.`groups`
ADD CONSTRAINT `group_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`);
--
-- Constraints for table `prospect`
--
ALTER TABLE `list_`.`prospect`
ADD CONSTRAINT `prospect_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`);
--
-- Constraints for table `seller`
--
ALTER TABLE `list_`.`seller`
ADD CONSTRAINT `seller_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`);
--
-- Constraints for table `settings`
--
ALTER TABLE `list_`.`settings`
ADD CONSTRAINT `settings_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`);
I think you slightly misunderstood the concept of Foreign Keys. Changing the name of a group is not supposed to reflect on any other table, you just change your group-table.
Assuming you have this simple scenario, where one Contact can belong only to one Group:
Groups
id
group_name
Contacts
id
group_id -> Groups.id
first_name
...
Your Contacts do not have the information about the group_name. You just store the reference to your Groups.id.
If you want to query your contacts and the name of their group, you join those two tables:
Select c.first_name, g.group_name
From contacts c
Join groups g On ( g.id = c.group_id )
If you want to change the name of a group, you do a simple update:
Update groups
Set group_name = 'Your new group name'
Where id = 99 --# The id of the group to rename
This only changes your Groups table, without changing your Contacts.
Your Foreign Key on Contacts.group_id is there to ensure the referential integrity. This means, that you are not allowed to have a contact with group_id=88 if there is no record in Groups with id=88.
Using ON DELETE CASCADE would delete all Contacts that are members of a certain group, once you delete that group.
I have got a problem with two tables:
CREATE TABLE IF NOT EXISTS `addresses` (
`adr_id` int(11) NOT NULL auto_increment,
`per_id` int(11) NOT NULL,
`adr_street` varchar(50) NOT NULL,
`adr_houseno` int(11) default NULL,
`adr_housenoadd` varchar(10) default NULL,
`adr_postalcode` varchar(25) NOT NULL,
`adr_city` varchar(20) NOT NULL,
`adr_type` varchar(45) default NULL,
`cnt_id` int(11) NOT NULL,
`adr_date` date default NULL,
`sys-mut-dt` timestamp NULL default NULL,
`sys-mut-user` varchar(20) default NULL,
`sys-mut-id` int(11) NOT NULL default '0',
PRIMARY KEY (`adr_id`),
KEY `per_id` (`per_id`),
KEY `cnt_id` (`cnt_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ;
--
-- RELATIES VOOR TABEL `addresses`:
-- `cnt_id`
-- `countries` -> `cnt_id`
-- `per_id`
-- `persons` -> `per_id`
--
CREATE TABLE `events` (
`evt_id` int(11) NOT NULL auto_increment,
`evt_name` varchar(50) NOT NULL,
`evt_description` varchar(100) default NULL,
`evt_startdate` date NOT NULL,
`evt_enddate` date default NULL,
`evt_starttime` time default NULL,
`evt_endtime` time default NULL,
`evt_amtpersons` int(11) default NULL,
`sts_id` int(11) NOT NULL,
`adr_id` int(11) default NULL,
`evt_amtPersonsSubs` tinyint(4) NOT NULL default '0',
`evt_photo` varchar(50) default NULL,
`sys-mut-dt` timestamp NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
`sys-mut-user` varchar(20) default NULL,
`sys-mut-id` int(11) NOT NULL default '0',
PRIMARY KEY (`evt_id`),
KEY `sts_id` (`sts_id`),
KEY `adr_id` (`adr_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
The problem is, when i try to delete a record from address table I get the following error
DELETE
FROM addresses
WHERE per_id = 45
1451 - Cannot delete or update a parent row: a foreign key constraint fails (`site/events`, CONSTRAINT `adr_id` FOREIGN KEY (`adr_id`) REFERENCES `addresses` (`adr_id`) ON DELETE NO ACTION ON UPDATE NO ACTION) ;
The weird thing is that there is no record with the same per_id or adr_id in the events table.
So what's going on over here?
How Can I solve this? ;-)
/* I think it means "How can I solve this?" */
It may sound stupid, but are you absolutely sure there are no child rows?
Could you please run this:
SELECT e.*
FROM addresses a
JOIN events e
ON e.adr_id = a.adr_id
WHERE a.per_id = 45