I've got this code to create an SQL table, however I'm facing a #1215 error.
CREATE TABLE ‘Categorie’ (
‘catID’ int(11) NOT NULL AUTO_INCREMENT,
‘naam’ varchar(20) NOT NULL,
‘prioriteit’ int(2) NOT NULL,
‘subCatVan’ int(11) DEFAULT NULL,
PRIMARY KEY (‘catID’),
CONSTRAINT ‘subCatVan’ FOREIGN KEY (‘subCatVan’) REFERENCES Categorie
(‘catID’) ON DELETE SET NULL ON UPDATE CASCADE
);
Help is appreciated!
As Jens already pointed out, there is an issue with your ticks. First, the identifier quote character in MySQL is the backtick (`) by default, second, you are not using ticks for the table name in your foreign key constraint.
Replace all ticks with backticks and your statement will work (even without ticks around the table name in the foreign key constraint). Leave all ticks out and your statement will work. Change REFERENCES Categorie to REFERENCES ‘Categorie’ and your statement will work (although probably not as expected).
I would recommend using backticks in all places as a good practice:
CREATE TABLE `Categorie` (
`catID` int(11) NOT NULL AUTO_INCREMENT,
`naam` varchar(20) NOT NULL,
`prioriteit` int(2) NOT NULL,
`subCatVan` int(11) DEFAULT NULL,
PRIMARY KEY (`catID`),
CONSTRAINT `subCatVan` FOREIGN KEY (`subCatVan`) REFERENCES `Categorie`
(`catID`) ON DELETE SET NULL ON UPDATE CASCADE
);
What currently happens is that you are actually not creating a table named Categorie, but instead a table named ‘Categorie’ (including the ticks). Because you are not using the same ticks in your foreign key constraint, MySQL looks for a table named Categorie without the ticks and thus cannot find the target for your reference.
try this
CREATE TABLE `Categorie` (
`catID` INT(11) NOT NULL AUTO_INCREMENT,
`naam` VARCHAR(20) NOT NULL,
`prioriteit` INT(2) NOT NULL,
`subCatVan` INT(11) DEFAULT NULL,
PRIMARY KEY (`catID`),
CONSTRAINT `subCatVan` FOREIGN KEY (`subCatVan`) REFERENCES Categorie
(`catID`) ON DELETE SET NULL ON UPDATE CASCADE
);
Related
I am creating 2 tables in my database:
DROP TABLE IF EXISTS `med_pharmacy`;
CREATE TABLE IF NOT EXISTS `med_pharmacy` (
`med_pharmacy_id` int(11) NOT NULL AUTO_INCREMENT,
`med_id` int(11) NOT NULL,
`med_barcode` varchar(45) DEFAULT NULL,
`med_received` date DEFAULT NULL,
`med_expiry` date DEFAULT NULL,
`med_tablet` int(11) DEFAULT NULL,
`med_pill` int(11) DEFAULT NULL,
`clinic_id` varchar(45) DEFAULT NULL,
PRIMARY KEY (`med_pharmacy_id`),
KEY `fk_med_pharmacy_medication1_idx` (`med_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1261 DEFAULT CHARSET=utf8mb4;
AND:
DROP TABLE IF EXISTS `medication`;
CREATE TABLE `medication` (
`med_id` int(11) NOT NULL,
`med_name` varchar(75) NOT NULL,
`med_date_added` date DEFAULT NULL,
`clinic_id` varchar(45) DEFAULT NULL,
`med_type` varchar(15) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
And when I run the queries in wamp I got this error:
SQL query:
ALTER TABLE `med_pharmacy`
ADD CONSTRAINT `fk_med_pharmacy_medication1`
FOREIGN KEY (`med_id`)
REFERENCES
`medication` (`med_id`) ON DELETE CASCADE ON UPDATE CASCADE MySQL
said: Documentation
#1822 - Failed to add the foreign key constaint. Missing index for constraint 'fk_med_pharmacy_medication1' in the referenced table
'medication'
The tables already exists but I changed one field.
The column referenced in a foreign key must be indexed. You need to add an index on medication.med_id. In fact, this should probably be the primary key of the table.
ALTER TABLE medication ADD PRIMARY KEY (med_id);
if you are giving
ADD CONSTRAINT `fk_med_pharmacy_medication1`
FOREIGN KEY (`med_id`)
A FOREIGN KEY constraint does not have to be linked only to a PRIMARY KEY constraint in another table; it can also be defined to reference the columns of a UNIQUE constraint in another table.
so med_id should have primary key in medication or reference the columns of a UNIQUE constraint
I am getting the following error:
Error Code: 1215. Cannot add foreign key constraint
This happens even if I remove all foreign key constraints. timeline table does exist in the database, so that is not the issue.
Can't seem to figure out what would cause this problem
USE study;
CREATE TABLE IF NOT EXISTS timelineStage(
timelineStageID INT NOT NULL AUTO_INCREMENT,
timelineID TINYINT NOT NULL,
stageName VARCHAR(100) NOT NULL,
stagePredecessorID INT NULL,
isStartup TINYINT NOT NULL DEFAULT 0,
timelineStageNotes VARCHAR(500) NULL,
recCreatedByUserID INT NOT NULL,
recCreatedTimeUTC TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
recUpdatedByUserID INT NOT NULL,
recUpdatedTimeUTC TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (timelineStageID),
UNIQUE KEY IX_U_timelineStage_stageName(stageName, timelineID),
UNIQUE KEY IX_U_timelineStage_stagePredecessor(stagePredecessorID, timelineID),
CONSTRAINT FK_timelineStage_timelineID
FOREIGN KEY (timelineID)
REFERENCES timeline(timelineID)
ON UPDATE CASCADE,
CONSTRAINT FK_timelineStage_stagePredecessorID
FOREIGN KEY (stagePredecessorID)
REFERENCES timelineStage(timelineStageID)
ON UPDATE CASCADE,
CONSTRAINT FK_timelineStage_recCreatedByUserID
FOREIGN KEY (recCreatedByUserID)
REFERENCES customer.user(userID)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT FK_timelineStage_recUpdatedByUserID
FOREIGN KEY (recUpdatedByUserID)
REFERENCES customer.user(userID)
ON DELETE NO ACTION
ON UPDATE NO ACTION
)
ADDING Timeline and customer.user
USE study;
CREATE TABLE timeline(
timelineID TINYINT NOT NULL AUTO_INCREMENT,
timelineName VARCHAR(100) NOT NULL,
timelineNotes VARCHAR(500) NULL,
recCreatedByUserID INT(11) NOT NULL,
recCreatedTimeUTC DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
recUpdatedByUserID INT(11) NOT NULL,
recUpdatedTimeUTC TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (timelineID)
)
CREATE TABLE customer.user(
userID INT NOT NULL AUTO_INCREMENT,
firstName VARCHAR(100) NOT NULL,
lastName VARCHAR(100) NOT NULL,
emailAddress VARCHAR(100) NOT NULL,
PRIMARY KEY (userID))
The problem was with neither of the other tables. It was is study table (another table).
timelineStageID was set to TINYINT and in timelineStage table timelineStageID was set to INT.
Matching all to INT fixed the problem.
Carefully check every references clause whether the referenced column really is present in the table.
Also try to first create the table and then add the constraints one by one so you exactly know which one failed.
The problem is about this code: REFERENCES customer.user
You cannot create a foreign key constraint referencing a table in another database.
I have 2 tables : tbl_usr_info which has a UID which is a primary key and auto-increment and tbl_login_info which has a LoginID (primary) and the UID along with some other information like timestamps etc.
I'm trying to reference UID from tbl_login_info with UID in tbl_usr_info by running this sql statement
CONSTRAINT `uid-info/login` FOREIGN KEY (`UID`) REFERENCES `tbl_usr_info` (`UID`)
but I'm getting this error:
Cannot add or update a child row: a foreign key constraint fails (CONSTRAINT uid-info/login FOREIGN KEY (UID) REFERENCES tbl_usr_info (UID))
tbl_usr_info table
CREATE TABLE `tbl_usr_info` (
`UID` int(50) NOT NULL AUTO_INCREMENT,
`username` varchar(50) NOT NULL DEFAULT '',
`password` varchar(50) NOT NULL DEFAULT '',
`email` varchar(50) NOT NULL DEFAULT '',
PRIMARY KEY (`UID`),
UNIQUE KEY `username` (`username`),
UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
tbl_usr_login table
CREATE TABLE `tbl_usr_login` (
`LoginID` int(11) NOT NULL AUTO_INCREMENT,
`UID` int(50) NOT NULL,
`ip_address` varchar(55) DEFAULT NULL,
`device` varchar(100) DEFAULT NULL,
`time_stamp` datetime DEFAULT NULL,
PRIMARY KEY (`LoginID`)
)ENGINE=InnoDB DEFAULT CHARSET=latin1;
Is it the order in which I'm referencing it that's wrong?
I tested your foreign key constraint and it works without error for me. But my tables were empty.
One of the most common types of failures for a foreign key constraint is that when you create the constraint, the child table contains some values that are not present in the parent table. The foreign key constraint cannot be satisfied in that case, so creation of the constraint fails.
You can check for unmatched UID values:
SELECT COUNT(*)
FROM tbl_usr_login AS l
LEFT OUTER JOIN tbl_usr_info AS i
ON l.UID = i.UID
WHERE i.UID is NULL;
P.S.: This is tangential to your question, but I notice you're using INT(50). The argument to INT doesn't mean what you think it means. INT(50) does NOT mean you can store 50 digits. See my answer to Types in MySQL: BigInt(20) vs Int(20)
To enable foreign key, child and parent column definitions must match along with some other conditions.
In your problem case, following steps should resolve it:
create user table.
create login info table.
add index/key on the UID column in login table.
now, add referential constraint on it.
Refer to:
Mysql: Using foreign key constraints:
https://dev.mysql.com/doc/refman/5.6/en/create-table-foreign-keys.html
I have a juction table that contains two foreign keys (from Profiles and Districts tables), with both columns as a composite primary key.
`profID` int(11) NOT NULL,
`distID` varchar(8) NOT NULL,
PRIMARY KEY (`profID`,`distID`)
I'd like to constrain both columns, but MySql throws an error:
#1050 - Table './database_name/z#002dprof#002ddist' already exists
In troubleshooting the problem, I've tried creating another duplicate junction table from scratch, but I get the same error. Oddly, MySQL will allow me to constrain one column or the other, but not both columns. I'm stumped, since I have other (non-junction) tables that have constraints on more than one foriegn key column.
By the way, I'm using phpMyAdmin, and all tables are InnoDB with utf-8.
Any help would be appreciated.
ADDED: SHOW CREATE TABLE results
CREATE TABLE `Profiles` (
`profID` int(11) NOT NULL AUTO_INCREMENT,
`email` varchar(64) NOT NULL,
`stID` varchar(2) NOT NULL,
`zip` varchar(5) NOT NULL,
PRIMARY KEY (`profID`),
KEY `stID` (`stID`,`zip`),
KEY `email` (`email`)
) ENGINE=InnoDB AUTO_INCREMENT=52 DEFAULT CHARSET=utf8
CREATE TABLE `Districts` (
`distID` varchar(8) NOT NULL,
`stID` varchar(2) NOT NULL,
`abbrev` varchar(16) NOT NULL,
PRIMARY KEY (`distID`),
KEY `stID` (`stID`),
) ENGINE=InnoDB DEFAULT CHARSET=utf8
CREATE TABLE `z-prof-dist` (
`profID` int(11) NOT NULL,
`distID` varchar(8) NOT NULL,
PRIMARY KEY (`profID`,`distID`),
KEY `distID` (`distID`),
KEY `profID` (`profID`),
CONSTRAINT `z-prof-dist_ibfk_1` FOREIGN KEY (`distID`) REFERENCES `Districts` (`distID`)
ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8
I think I found a fix. Rather than using the phpMyAdmin function for adding a constraint (where I kept getting the error message), I instead followed marekful's lead by using an SQL ALTER TABLE query (with a new constraint name) as such:
ALTER TABLE `z-prof-dist`
ADD CONSTRAINT `test1`
FOREIGN KEY (`profID`) REFERENCES `Profiles` (`profID`)
ON UPDATE CASCADE
I still don't understand the cause of the original error, but I can see that the newly added foreign key constraint is working perfectly.
I got this error when create table: Foreign key constraint is incorrectly formed?
create table comment(
Comment_ID int UNSIGNED AUTO_INCREMENT not null,
User_1 varchar(50) not null,
Note_ID int(11) UNSIGNED not null,
PRIMARY key(Comment_ID),
CONSTRAINT `fk_1` FOREIGN KEY (`User_1`) REFERENCES `user` (`Dev_ID`),
CONSTRAINT `fk_2` FOREIGN KEY (`User_2`) REFERENCES `user` (`Dev_ID`),
CONSTRAINT `fk_3` FOREIGN KEY (`Note_ID`) REFERENCES `note`(`Note_ID`)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
it's OK when I remove fk_3.
This my note table
CREATE TABLE `note` (
`Dev_ID` varchar(50) NOT NULL,
`Note_ID` int(11) UNSIGNED NOT NULL,
`Title` varchar(200) NOT NULL,
`Time` datetime NOT NULL,
`Mood` int(11) NOT NULL,
`Body` varchar(3000) NOT NULL,
`Visible` tinyint(1) NOT NULL DEFAULT '1',
`Share` tinyint(1) NOT NULL DEFAULT '0',
`Update` tinyint(1) NOT NULL DEFAULT '0',
PRIMARY KEY (`Dev_ID`,`Note_ID`),
CONSTRAINT `fk_note_user` FOREIGN KEY (`Dev_ID`)
REFERENCES `user` (`Dev_ID`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8
Thanks for help!
That's because the primary key of the note table is (Dev_ID,Note_ID) but you are only referencing one of those columns (Note_ID) in your constraint.
A FK constraint must always consist of all PK columns.
Also make sure that both tables are innoDB.
In addition to the answers that have been given, you would also get this error if the field types did not match. For example, if you tried to create a foreign key constraint between a varchar field and an int field.
This problem occur because the column
`Note_ID` int(11) UNSIGNED NOT NULL
Is neither primary nor unique.
Just make it
`Note_ID` int(11) UNSIGNED NOT NULL UNIQUE
And it will work.
One more addition: charsets of the fields must match.
In the referenced table I had ascii as a default charset: DEFAULT CHARSET=ascii was reported by show create table. I tried to create the referencing table with DEFAULT CHARSET=utf and I got 'Foreign key constraint is incorrectly formed'.
After I changed this to DEFAULT CHARSET=ascii on the new table (the referencing one), it was created successfully.
Ensure the collation is the same on both fields. I had the same problem when one was latin-general-ci and the other was utf8_unicode_ci. Not sure why the collation changed on the one table but fixing this resolved the issue.