I have the following table in a MySQL database:
CREATE TABLE `datavalues` (
`ValueID` int(11) NOT NULL AUTO_INCREMENT,
`DataValue` double NOT NULL,
`ValueAccuracy` double DEFAULT NULL,
`LocalDateTime` datetime NOT NULL,
`UTCOffset` double NOT NULL,
`DateTimeUTC` datetime NOT NULL,
`SiteID` int(11) NOT NULL,
`VariableID` int(11) NOT NULL,
`OffsetValue` double DEFAULT NULL,
`OffsetTypeID` int(11) DEFAULT NULL,
`CensorCode` varchar(50) COLLATE utf8_unicode_ci NOT NULL DEFAULT 'nc',
`QualifierID` int(11) DEFAULT NULL,
`MethodID` int(11) NOT NULL DEFAULT '0',
`SourceID` int(11) NOT NULL,
`SampleID` int(11) DEFAULT NULL,
`DerivedFromID` int(11) DEFAULT NULL,
`QualityControlLevelID` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`ValueID`),
UNIQUE KEY `DataValues_UNIQUE_DataValues` (`DataValue`,`ValueAccuracy`,`LocalDateTime`,`UTCOffset`,`DateTimeUTC`,`SiteID`,`VariableID`,`OffsetValue`,`OffsetTypeID`,`CensorCode`,`QualifierID`,`MethodID`,`SourceID`,`SampleID`,`DerivedFromID`,`QualityControlLevelID`),
KEY `FK_DataValues_Sites` (`SiteID`),
KEY `FK_DataValues_Sources` (`SourceID`),
KEY `FK_DataValues_QualityControlLevels` (`QualityControlLevelID`),
KEY `FK_DataValues_OffsetTypes` (`OffsetTypeID`),
KEY `FK_DataValues_CensorCodeCV` (`CensorCode`),
KEY `FK_DataValues_Variables` (`VariableID`),
KEY `FK_DataValues_Methods` (`MethodID`),
KEY `FK_DataValues_Qualifiers` (`QualifierID`),
KEY `FK_DataValues_Samples` (`SampleID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci
ALTER TABLE `datavalues`
ADD CONSTRAINT `FK_DataValues_Sites` FOREIGN KEY (`SiteID`) REFERENCES `sites` (`SiteID`) ON DELETE NO ACTION ON UPDATE CASCADE,
ADD CONSTRAINT `FK_DataValues_Sources` FOREIGN KEY (`SourceID`) REFERENCES `sources` (`SourceID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `FK_DataValues_QualityControlLevels` FOREIGN KEY (`QualityControlLevelID`) REFERENCES `qualitycontrollevels` (`QualityControlLevelID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `FK_DataValues_OffsetTypes` FOREIGN KEY (`OffsetTypeID`) REFERENCES `offsettypes` (`OffsetTypeID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `FK_DataValues_CensorCodeCV` FOREIGN KEY (`CensorCode`) REFERENCES `censorcodecv` (`Term`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `FK_DataValues_Variables` FOREIGN KEY (`VariableID`) REFERENCES `variables` (`VariableID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `FK_DataValues_Methods` FOREIGN KEY (`MethodID`) REFERENCES `methods` (`MethodID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `FK_DataValues_Qualifiers` FOREIGN KEY (`QualifierID`) REFERENCES `qualifiers` (`QualifierID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `FK_DataValues_Samples` FOREIGN KEY (`SampleID`) REFERENCES `samples` (`SampleID`) ON DELETE NO ACTION ON UPDATE NO ACTION;
When I open my database in PhpMyAdmin 4.0.3 and run a query:
SELECT MAX(DateTimeUTC) from `datavalues`
the query executes but PhpMyAdmin shows a
warning:
This table does not contain a unique column. Grid edit, checkbox,
Edit, Copy and Delete features are not available.
How is it possible? I thought that if I have one column with PRIMARY KEY constraint then the column is UNIQUE. Could this be a bug in PhpMyAdmin? I'm confused.
I found the answer: The warning:
This table does not contain a unique column. Grid edit, checkbox,
Edit, Copy and Delete features are not available.
applies to the current result set and not to the original table.
Álvaro G. Vicario's comment is right.
This appears to be a new thing in PhpMyAdmin 4.0.4 and I find this type of message more confusing than useful.
All you got to do is add a unique column like one called id with a index = PRIMARY like the pic, or if you have one already that is called id that are numbers just make it PRIMARY
Related
I am having trouble adding multiple foreign key constraints to this table. I get an error saying
Foreign key constraint is incorrectly formed
Both id's referenced are primary keys in their respective tables. What am I doing wrong?
CREATE TABLE `works_on` (
`eid` int(11) DEFAULT NULL,
`pid` int(11) DEFAULT NULL,
`start_date` date NOT NULL,
PRIMARY KEY (`eid`, `pid`),
CONSTRAINT `works_on_ibfk_1` FOREIGN KEY (`eid`)
REFERENCES `employee` (`id`) ON DELETE SET NULL ON UPDATE CASCADE,
CONSTRAINT `works_on_ibfk_2` FOREIGN KEY (`pid`)
REFERENCES `project` (`id`) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB
You have a paradox here - you cannot have a primary key where any of the elements has a null values AND therefore you cannot on delete SET NULL..
You should also be seeing an error message telling you that the primary key is invalid..
I have a problem here.
I cannot add this to my db because one table is dependent of another and vice-versa.
So I get
Cannot add foreign key constraint
on the first create table that I put
How can I add this 2 tables if they both have constraints??
-- User Roles
CREATE TABLE IF NOT EXISTS `user_roles` (
`user_role_id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(45) NOT NULL,
`role` varchar(45) NOT NULL,
PRIMARY KEY (`user_role_id`),
UNIQUE KEY `uni_username_role` (`role`,`username`),
UNIQUE KEY `ix_auth_username` (`username`,`role`),
KEY `fk_username_idx` (`username`),
CONSTRAINT `fk_username` FOREIGN KEY (`username`) REFERENCES `users` (`username`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;
-- Users
CREATE TABLE IF NOT EXISTS `users` (
`username` varchar(45) NOT NULL,
`name` varchar(45) DEFAULT NULL,
`hashedPassword` varchar(500) NOT NULL,
`enabled` tinyint(1) NOT NULL DEFAULT '1',
`image` mediumblob,
`team` int(11) DEFAULT NULL,
`userRole` int(11) DEFAULT NULL,
PRIMARY KEY (`username`),
KEY `fkteam_idx` (`team`),
KEY `fkrole_idx` (`userRole`),
CONSTRAINT `fkrole` FOREIGN KEY (`userRole`) REFERENCES `user_roles` (`user_role_id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `fkteam` FOREIGN KEY (`team`) REFERENCES `team` (`idteam`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
To do this, you'll need to use deferrable constraint checks, but unfortunately MySQL does not implement this standard SQL feature.
As far as I know, only Oracle and PostgreSQL support this feature (deferrable constraints). These constraints are checked at the end of the transaction, and not on every single row insertion. That would solve your problem.
Therefore, you have two options:
Switch to Oracle or PostgreSQL (unlikely, I guess) or,
Change your table definition to allow one of the foreign key constraints to accept null values.
In the second case, you would:
Insert in the table that allow null in the FK, getting the generated ID.
Insert in the other table using the ID. Then, get the second generated ID.
Update the null in first table using the second ID.
Commit.
That's it.
I've recently started trying to use foreign keys to make database management easier on myself. I'm having a terrible time trying to figure out how they actually work, and most of the time I can get it working between tables without issue. But I'm currently having an issue with 2 of my tables, and I can't figure it out.
I'm getting an error:
SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or
update a child row: a foreign key constraint fails
(REDACTED.rc_logs, CONSTRAINT rc_logs_ibfk_1 FOREIGN
KEY (user_id) REFERENCES rc_teammates (uid) ON DELETE CASCADE ON
UPDATE CASCADE)
[/home5/redacted/public_html/redacted/rc/public/assets/php/connection.php:25]
but my tables seem to be set up properly, and I'm really confused about why it's not working. Here is my table structures:
rc_teammates
CREATE TABLE `rc_teammates` (
`uid` int(11) NOT NULL,
`name` text NOT NULL,
`primary_line` int(11) NOT NULL,
`hireStatus` text NOT NULL,
`created_on` date NOT NULL,
`active` tinyint(1) NOT NULL DEFAULT '1'
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
ALTER TABLE `rc_teammates`
ADD PRIMARY KEY (`uid`), ADD UNIQUE KEY `uid` (`uid`), ADD KEY `primary_line` (`primary_line`), ADD KEY `primary_line_2` (`primary_line`);
ALTER TABLE `rc_teammates`
MODIFY `uid` int(11) NOT NULL AUTO_INCREMENT;
ALTER TABLE `rc_teammates`
ADD CONSTRAINT `rc_teammates_ibfk_1` FOREIGN KEY (`primary_line`) REFERENCES `rc_lines` (`uid`) ON DELETE CASCADE ON UPDATE CASCADE;
rc_logs
CREATE TABLE IF NOT EXISTS `rc_logs` (
`uid` int(11) NOT NULL,
`user_id` int(11) NOT NULL,
`line` int(11) NOT NULL,
`date` date NOT NULL,
`type` varchar(15) NOT NULL,
`timein` time NOT NULL,
`timeout` time NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=53 DEFAULT CHARSET=latin1;
ALTER TABLE `rc_logs`
ADD PRIMARY KEY (`uid`), ADD KEY `user_id` (`user_id`), ADD KEY `line` (`line`), ADD KEY `user_id_2` (`user_id`);
ALTER TABLE `rc_logs`
MODIFY `uid` int(11) NOT NULL AUTO_INCREMENT,AUTO_INCREMENT=53;
ALTER TABLE `rc_logs`
ADD CONSTRAINT `rc_logs_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `rc_teammates` (`uid`) ON DELETE CASCADE ON UPDATE CASCADE,
ADD CONSTRAINT `rc_logs_ibfk_2` FOREIGN KEY (`line`) REFERENCES `rc_lines` (`uid`) ON DELETE CASCADE ON UPDATE CASCADE;
I've tried to look up the error, and I've had this issue before but I do not remember how I solved it. What's worse is, this was working earlier, until I emptied the rc_teammates table to start fresh.
I really cannot figure this out, and would love any pointers. Thanks!
As you said you have "emptied" (TRUNCATE?) the table rc_teammates.
And you try to insert a record in rc_logs, and this record has a user_id that doesn't exists in rc_teammates, thus violation of the following constraint:
ADD CONSTRAINT `rc_logs_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `rc_teammates` (`uid`) ON DELETE CASCADE ON UPDATE CASCADE
Just add a record in rc_teammates, having a uid equal to the user_id of the record you are trying to insert in rc_logs, and retry.
Also, about this :
ALTER TABLE `rc_teammates`
ADD PRIMARY KEY (`uid`), ADD UNIQUE KEY `uid` (`uid`),
ALTER TABLE `rc_teammates`
MODIFY `uid` int(11) NOT NULL AUTO_INCREMENT;
When you set a column as PRIMARY KEY, it is de facto : UNIQUE, NOT NULL and INDEXED. You don't need to specify all this, PRIMARY KEY is enough. This is valid for your other table as well.
I have three tables: advocate, client and event. In event table, I have two fields that are referencing two fields from advocate table and one field referencing client, and when I try to add foreign key I get this cannot add foreign key constraint error.
create table advocate(
ida int(11) not null,
idk int(11) not null,
#...
primary key(ida, idk)
)engine = InnoDB default charset=utf8;
create table client(
jmb varchar(13) not null primary key
#...
)engine=InnoDB default charset=utf8;
create table event(
ida int(11) not null,
idk int(11) not null,
jmb varchar(13) not null,
#...
primary key(ida,idk,jmb),
foreign key(ida, idk)
references advocate(ida, idk)
on update cascade
on delete restrict,
foreign key(jmb)
references client.jmb
on update cascade
on delete restrict
)engine=InnoDB default charset=utf8;
Can you try changing:
foreign key(jmb)
references client.jmb
on update cascade
on delete restrict
to
foreign key(jmb)
references client (jmb)
on update cascade
on delete restrict
I have a custom table created which has a foreign constraint on the core_website table. However, the on delete cascade isn't working.
I did a search and found this relevant thread, which notes that the data types between the two columns have to be the same. Both data types are smallint(5).
I did notice one minor discrepancy in the column definition, which is that in core_website, Allow Null is not set, and Default is not set to zero, whereas in the account table, Allow Null is set and Default is zero. I didn't think changing these would have any effect, but I went ahead and changed them on the account table to match, but that didn't help.
CREATE TABLE `account` (
`account_id` smallint(11) unsigned NOT NULL AUTO_INCREMENT,
`website_id` smallint(5) unsigned DEFAULT '0',
`code` varchar(64) NOT NULL DEFAULT '',
PRIMARY KEY (`account_id`),
UNIQUE KEY `code` (`code`),
KEY `FK_WEBSITE_ID` (`website_id`),
CONSTRAINT `FK_WEBSITE_ID` FOREIGN KEY (`website_id`) REFERENCES `core_website` (`website_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=44 DEFAULT CHARSET=utf8
try this and let us the result pls.
CREATE TABLE `account` (
`account_id` smallint(11) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,
`website_id` smallint(5) unsigned DEFAULT '0',
`code` varchar(64) NOT NULL DEFAULT '',
UNIQUE KEY `code` (`code`),
KEY `FK_WEBSITE_ID` (`website_id`),
CONSTRAINT `FK_WEBSITE_ID` FOREIGN KEY (`website_id`) REFERENCES `core_website` (`website_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=44 DEFAULT CHARSET=utf8
You need add foreign key to core_website table and point it to website_id field in account table. In other words, foreign key should be added to the dependent table and pointed to main table, in this case when you delete row from main table - row from dependent table will be deleted because of FK. In your case you did it "upside down".