hey guys, i'm getting this error.
Error 1452 : Cannot add or update a child row: a foreign key constraint fails (`s2794971db/ProfileInterests`, CONSTRAINT `ProfileInterests_ibfk_2` FOREIGN KEY (`InterestID`) REFERENCES `Interests` (`ID`))
I change my tables from myISAM to innodb...found out I needed to so that delete was easier.
I had issues with it so I deleted the table which I needed to create the relationships with.
Then I made it again
I originally had
create table if not exists Users (
ID int not null auto_increment primary key,
FirstName varchar(40) not null,
LastName varchar(40) not null,
UserName varchar(40) not null,
UserEmail varchar(40) not null,
UserDOB timestamp not null,
UserJoin datetime not null
);
create table if not exists Interests(
ID int not null auto_increment primary key,
Interests varchar(40) not null
);
create table if not exists ProfileInterests (
userID int not null References Users(ID),
InterestID int not null References Interests(ID),
MiddleID int not null auto_increment primary key
);
but then I deleted the last table and made it
create table if not exists ProfileInterests (
userID int not null,
InterestID int not null,
MiddleID int not null auto_increment primary key
);
and then I made userID and InterestID into index's and then I added a relation User-> ID for userID and interests->ID for interestID
the error occurs when i'm trying to input data into via a php form.
Any ideas...really need some help!
Obviously, you're trying to insert a record into ProfileInterests for which there is no matching record in the Interests table. Look at the exact insert query, and check that you're supplying a valid value for every field in the table which is part of a foreign key relationship.
Related
Good evening,
following table situation:
create table TableA (
pkA int not null auto_increment,
propertyA varchar(20),
primary key (pkA) );
create table TableB (
pkB int not null auto_increment,
pkA int not null,
propertyB varchar(20),
primary key (pkB),
foreign key (pkA) references TableA (pkA) on delete cascade);
create table TableC (
pkC int not null auto_increment,
pkB int not null,
propertyC varchar(20),
primary key (pkC),
foreign key (pkB) references TableB (pkB) on delete cascade );
When I delete a row from parent table 'TableA' I need to know which rows (primary keys) got deleted in 'TableB' and 'TableC' as well.
I am working with PHP 7.0. I was hoping there is something like mysqli_insert_id for deletes, but... nada :(
Any ideas?
Hi I'm having issues creating my post database. I'm trying to make a forenge key to link to my users database. Can someone please help?
Here's the code for my tables :
CREATE TABLE USERS(
UserID int NOT NULL AUTO_INCREMENT,
UserName varchar(255),
UserPassword varchar(255) NOT NULL,
UserEmailAddress varchar(255) NOT NULL,
Admin int DEFAULT 0,
PRIMARY KEY (userID,UserName)
)ENGINE=InnoDB;
CREATE TABLE POSTS(
postID int NOT NULL AUTO_INCREMENT,
postTitle varchar(255) NOT NULL,
postContent varchar(255) NOT NULL,
category varchar(255) NOT NULL,
postDate Date NOT NULL,
postAuthor varchar(255),
tag varchar(255),
PRIMARY KEY(postID),
FOREIGN KEY(postAuthor) REFERENCES USERS(UserName)
)ENGINE=InnoDB;
Here's the last InnoDB error message:
Error in foreign key constraint of table db/POSTS:
FOREIGN KEY(postAuthor) REFERENCES USERS(UserName)
)ENGINE=InnoDB:
Cannot find an index in the referenced table where the
referenced columns appear as the first columns, or column types
in the table and the referenced table do not match for constraint.
Note that the internal storage type of ENUM and SET changed in
tables created with >= InnoDB-4.1.12, and such columns in old tables
cannot be referenced by such columns in new tables.
See http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html
for correct foreign key definition.
There really should not be a good reason to have a compound primary key on the first table. So, I think you intend:
CREATE TABLE USERS (
UserID int NOT NULL AUTO_INCREMENT,
UserName varchar(255),
UserPassword varchar(255) NOT NULL,
UserEmailAddress varchar(255) NOT NULL,
Admin int DEFAULT 0,
PRIMARY KEY (userID),
UNIQUE (UserName)
);
CREATE TABLE POSTS (
postID int NOT NULL AUTO_INCREMENT,
postTitle varchar(255) NOT NULL,
postContent varchar(255) NOT NULL,
category varchar(255) NOT NULL,
postDate Date NOT NULL,
postAuthor int,
tag varchar(255),
PRIMARY KEY(postID),
FOREIGN KEY(postAuthor) REFERENCES USERS(UserId)
);
Some notes:
An auto-incremented id is unique on every row. It makes a good primary key.
A primary key can consist of multiple columns (called a composite primary key). However, an auto-incremented id doesn't make much sense as one of the columns. Just use such an id itself.
If you use a composite primary key, then the foreign key references need to include all columns.
I chose UserId for the foreign key reference. You could also use UserName (because it is unique).
UserName is a bad choice for foreign keys, because -- conceivably -- a user could change his or her name.
The error is caused by incorrect foreign key definition. In the concrete case you are missing a complete column in your foreign key definition.
In the USERS table you have defined primary key as composite key of UserID and UserName columns.
CREATE TABLE USERS (
UserID int NOT NULL AUTO_INCREMENT,
UserName varchar(255),
UserPassword varchar(255) NOT NULL,
UserEmailAddress varchar(255) NOT NULL,
Admin int DEFAULT 0,
PRIMARY KEY (UserID,UserName)
) ENGINE=InnoDB;
note that it is good practice to respect case of the identifiers (column names)
In the POSTS table you declared your foreign key to reference only one column in the USERS table, the UserName column. This is incorrect as you need to reference entire primary key of the USERS table which is (UserID, UserName). So to fix the error you need to add one additional column to the POSTS table and change your foreign key definition like this:
CREATE TABLE POSTS(
postID int NOT NULL AUTO_INCREMENT,
postTitle varchar(255) NOT NULL,
postContent varchar(255) NOT NULL,
category varchar(255) NOT NULL,
postDate Date NOT NULL,
authorId int,
postAuthor varchar(255),
tag varchar(255),
PRIMARY KEY(postID),
FOREIGN KEY(authorId, postAuthor) REFERENCES USERS(UserID, UserName)
) ENGINE=InnoDB;
Please look at following fiddle: http://sqlfiddle.com/#!9/92ff1/1
NOTE: If you can you should re-architect this to not use the composite primary key in the USERS table as it does not make sense from what I can see in the displayed code. You can change the tables like this:
CREATE TABLE USERS (
UserID int NOT NULL AUTO_INCREMENT,
UserName varchar(255),
UserPassword varchar(255) NOT NULL,
UserEmailAddress varchar(255) NOT NULL,
Admin int DEFAULT 0,
PRIMARY KEY (UserID)
) ENGINE=InnoDB;
CREATE TABLE POSTS (
postID int NOT NULL AUTO_INCREMENT,
postTitle varchar(255) NOT NULL,
postContent varchar(255) NOT NULL,
category varchar(255) NOT NULL,
postDate Date NOT NULL,
postAuthorID int,
tag varchar(255),
PRIMARY KEY(postID),
FOREIGN KEY(postAuthorID) REFERENCES USERS(UserID)
) ENGINE=InnoDB;;
I have 1 user and I want to insert more than one language(and degree) to him. How can I do this with php?
My languagetype table(all languages inserted)
CREATE TABLE TLANGUAGETYPE (
ID INT NOT NULL AUTO_INCREMENT,
language VARCHAR(100) NOT NULL,
PRIMARY KEY (ID)
)
My language table connected with user table.
CREATE TABLE TLANGUAGE (
languageID INT NOT NULL AUTO_INCREMENT,
userID INT NOT NULL,
ID INT NOT NULL,
degree FLOAT,
PRIMARY KEY (languageID),
FOREIGN KEY (userID) REFERENCES TUSER(userID),
FOREIGN KEY (ID) REFERENCES TLANGUAGETYPE(ID)
)
Instead of adding the languageId in user Table. You can create a mapping table which just contains the "USERID" and "LanguageID" columns.
here is my code
CREATE TABLE IF NOT EXISTS items
(
id INT NOT NULL AUTO_INCREMENT,
name varchar(256) ,
description TEXT,
price INT ,
images TEXT,
views INT ,
hidden TEXT,
purchases INT,
PRIMARY KEY (id)
);
CREATE TABLE IF NOT EXISTS methods
(
method_id INT NOT NULL AUTO_INCREMENT,
method varchar(256),
username varchar(256),
password varchar(256),
PRIMARY KEY (method_id)
);
CREATE TABLE IF NOT EXISTS payments
(
payment_id INT NOT NULL AUTO_INCREMENT,
item_id INT NOT NULL,
method varchar(256),
display INT,
PRIMARY KEY (payment_id) ,
FOREIGN KEY (item_id) REFERENCES items (id) ON DELETE CASCADE ON UPDATE CASCADE,
FOREIGN KEY (method) REFERENCES methods (method) ON DELETE CASCADE ON UPDATE CASCADE
)ENGINE=InnoDB DEFAULT CHARSET=latin1;
The first 2 tables gets generated ok, but the third one "payments" gives me error code 150 ! which should be related to FK ?!
any help ?
The primary key in the methods table is method_id not method. And the data type is INT not VARCHAR(256)
You need:
CREATE TABLE IF NOT EXISTS payments
(
payment_id INT NOT NULL AUTO_INCREMENT,
item_id INT NOT NULL,
method_id int, -- this is different
display INT,
PRIMARY KEY (payment_id) ,
FOREIGN KEY (item_id) REFERENCES items (id) ON DELETE CASCADE ON UPDATE CASCADE,
-- and this line is different
FOREIGN KEY (method_id) REFERENCES methods (method_id) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
I have a question I'm trying to have the q_id column take the value of the id column when a tag is submitted I have been trying to do this using PHP but I was thinking should I just add AUTO INCREMENT to the q_id column since but tables are updated when the tag is submited. or is this the wrong way to do it or is there a better way to do this?
Here is the MySQL tables below.
CREATE TABLE q_tags (
q_id INT UNSIGNED NOT NULL,
users_q_id INT UNSIGNED NOT NULL
);
CREATE TABLE tags (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
tag VARCHAR(255) NOT NULL,
PRIMARY KEY (id)
);
AUTO INCREMENT is used mainly to avoid adding the same ID into a table, so that you can keep a loyal index. I'd suggest you add a primary key to the q_tags, and change the current q_id to a foreign key, so that it can become a reference to tags table.
EDIT :
CREATE TABLE q_tags (
q_id INT UNSIGNED NOT NULL AUTO_INCREMENT,
t_id INT UNSIGNED NOT NULL,
users_q_id INT UNSIGNED NOT NULL,
PRIMARY KEY (q_id)
);
CREATE TABLE tags (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
tag VARCHAR(255) NOT NULL,
PRIMARY KEY (id)
);
t_id in the first table is the "foreign key". You can add it as a real mysql foreign key or just keep it this way (if you're planning on be able to "cascade delete" tags and t_tags related, it would matter)