re-create table results in errno 150 on MySql-DB - mysql

I created a table named "Payments" and later on realized, that I needed to change the names and datatypes of 2 of its columns. I dropped the table and wanted to create it again - but now I get the error-message: "Can't create table 'dev_datenbank.payment' (errno: 150)"
CREATE TABLE Payment(
payment_id INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
payment_gemeindeid INTEGER NOT NULL,
payment_initiator TIMESTAMP,
payment_zyklus INTEGER,
payment_received BOOLEAN DEFAULT false
);
ALTER TABLE Payment ADD FOREIGN KEY(payment_gemeindeid) REFERENCES Gemeinde(gemeinde_id);
I looked at similar problems here, but I haven't found a solution. Most of the times when others encountered this problem, it had to do with tables having different datatypes on the FK columns. But in my case both are INTEGER.
Also the database-type of all columns is 'InnoDB'.
I assume that the foreign key constraint has not correctly been removed from MySQL. I checked in the table KEY_COLUMN_USAGE in the information_schema but I cannot see any remains here.
The other table is created as follows:
CREATE TABLE Gemeinde
(gemeinde_id INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
gemeinde_name VARCHAR(50) NOT NULL,
gemeinde_amt INTEGER,
gemeinde_status INTEGER NOT NULL DEFAULT 1,
gemeinde_info VARCHAR(512)
);


Create an index on payment_gemeindeid before using it as a foreign key.


The problems I had, disappered after I updated my XAMPP from an old version (5.0.x) to a newer version (5.5.30). Now I can drop an recreate tables as expected.
Anyhow the hints with indexing my foreign keys was really helpful and I will start doing this from now on. I never paid much attention to this before, since my DBs were rather small. Thanks for your help.
Also reading through following discussion helped me get more understanding to this: Does a foreign key automatically create an index?

Related

SQL foreign keys incorrectly formed

Hello dear Stackoverflow users,
I'm working on a database to add to my project.
But I'm having struggles figuring out properly making relations in MySQL using PHPmyadmin.
I have written the following:
CREATE TABLE Orders (
OrderID int(255) NOT NULL,
Price decimal(65,2),
Order_date DATE,
UserID Int(255) NOT NULL,
PRIMARY KEY (OrderID),
FOREIGN KEY (UserID) REFERENCES Users(UserID)
);
CREATE TABLE Users(
UserID Varchar(255) NOT NULL,
Password Varchar(12) NOT NULL,
PRIMARY KEY(UserID)
);
But I keep getting an error telling me that I incorrectly formed the foreign key.
Am I missing something? does PHPmyadmin use a different way of formulating queries?
I have seen sources telling me to use index or later on using table modifiers and indexes to assign primary and foreign keys, but that seemed rather like unnecessary extra steps, unless it's really the only way to do it. My knowledge is yet still limited.
Error message: (errno: 150 "Foreign key constraint is incorrectly formed")

The tables creation order is critical - you cannot refer to the table which is not created. So create Users firstly then Orders.
Your referencing columns datatypes are not compatible - Users.UserID is defined as Varchar(255) whereas Orders.User_id is defined as Int(255). You must set the same datatype in both tables. For id column INT datatype seems to be the most reasonable.
PS. Int(255) is not safe, INTEGER datatype cannot store 255 digits. And the length specifying will be ignored anycase. Moreover, it is deprecated, so remove it at all.

Maybe can you try change the order of create tables? Try create first User and then Orders

what is wrong with this foreign key constraints [duplicate]

I have two tables, table1 is the parent table with a column ID and table2 with a column IDFromTable1 (not the actual name) when I put a FK on IDFromTable1 to ID in table1 I get the error Foreign key constraint is incorrectly formed error. I would like to delete table 2 record if table1 record gets deleted. Thanks for any help
ALTER TABLE `table2`
ADD CONSTRAINT `FK1`
FOREIGN KEY (`IDFromTable1`) REFERENCES `table1` (`ID`)
ON UPDATE CASCADE
ON DELETE CASCADE;
Let me know if any other information is needed. I am new to mysql

I ran into this same problem with HeidiSQL. The error you receive is very cryptic. My problem ended up being that the foreign key column and the referencing column were not of the same type or length.
The foreign key column was SMALLINT(5) UNSIGNED and the referenced column was INT(10) UNSIGNED. Once I made them both the same exact type, the foreign key creation worked perfectly.

For anyone facing this problem, just run
SHOW ENGINE INNODB STATUS
and see the LATEST FOREIGN KEY ERROR section for details.

I had the same problem when the parent table was created using MyISAM engine. It's a silly mistake, which I fixed with:
ALTER TABLE parent_table ENGINE=InnoDB;

make sure columns are identical(of same type) and if reference column is not primary_key, make sure it is INDEXED.

Syntax for defining foreign keys is very forgiving, but for anyone else tripping up on this, the fact that foreign keys must be "of the same type" applies even to collation, not just data type and length and bit signing.
Not that you'd mix collation in your model (would you?) but if you do, be sure your primary and foreign key fields are of the same collation type in phpmyadmin or Heidi SQL or whatever you use.
Hope this saves you the four hours of trial and error it cost me.

I had same problem, but solved it.
Just make sure that column 'ID' in 'table1' has UNIQUE index!
And of course the type, length of columns 'ID' and 'IDFromTable1' in these two tables has to be same. But you already know about this.

mysql error texts doesn't help so much, in my case, the column had "not null" constraint, so the "on delete set null" was not allowed

Just for completion.
This error might be as well the case if you have a foreign key with VARCHAR(..) and the charset of the referenced table is different from the table referencing it.
e.g. VARCHAR(50) in a Latin1 Table is different than the VARCHAR(50) in a UTF8 Table.

One more probable cause for the display of this error. The order in which I was creating tables was wrong. I was trying to reference a key from a table that was not yet created.

I had the same issue, both columns were INT(11) NOT NULL but I wan't able to create the foreign key.
I had to disable foreign keys checks to run it successfully :
SET FOREIGN_KEY_CHECKS=OFF;
ALTER TABLE ... ADD CONSTRAINT ...
SET FOREIGN_KEY_CHECKS=ON;
Hope this helps someone.

if everything is ok, just add ->unsigned(); at the end of foregin key.
if it does not work, check the datatype of both fields. they must be the same.

(Last Resent) Even if the field name and data type is the same but the collation is not the same, it will also result to that problem.
For Example
TBL
NAME | DATA
TYPE |
COLLATION
ActivityID | INT |
latin1_general_ci
ActivityID | INT |
utf8_general_ci
Try Changing it into
TBL
NAME | DATA
TYPE |
COLLATION
ActivityID | INT |
latin1_general_ci
ActivityID | INT |
latin1_general_ci
....
This worked for me.

This problem also occur in Laravel when you have the foreign key table table1 migration after the migration in which you reference it table2.
You have to preserve the order of the migration in order to foreign key feature to work properly.
database/migrations/2020_01_01_00001_create_table2_table.php
database/migrations/2020_01_01_00002_create_table1_table.php
should be:
database/migrations/2020_01_01_00001_create_table1_table.php
database/migrations/2020_01_01_00002_create_table2_table.php

Check the tables engine, both tables have to be the same engine, that helped me so much.

Although the other answers are quite helpful, just wanted to share my experience as well.
I faced the issue when I had deleted a table whose id was already being referenced as foreign key in other tables (with data) and tried to recreate/import the table with some additional columns.
The query for recreation (generated in phpMyAdmin) looked like the following:
CREATE TABLE `the_table` (
`id` int(11) NOT NULL, /* No PRIMARY KEY index */
`name` varchar(255) NOT NULL,
`name_fa` varchar(255) NOT NULL,
`name_pa` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
... /* SOME DATA DUMP OPERATION */
ALTER TABLE `the_table`
ADD PRIMARY KEY (`id`), /* PRIMARY KEY INDEX */
ADD UNIQUE KEY `uk_acu_donor_name` (`name`);
As you may notice, the PRIMARY KEY index was set after the creation (and insertion of data) which was causing the problem.
Solution
The solution was to add the PRIMARY KEY index on table definition query for the id which was being referenced as foreign key, while also removing it from the ALTER TABLE part where indexes were being set:
CREATE TABLE `the_table` (
`id` int(11) NOT NULL PRIMARY KEY, /* <<== PRIMARY KEY INDEX ON CREATION */
`name` varchar(255) NOT NULL,
`name_fa` varchar(255) NOT NULL,
`name_pa` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Try running following:
show create table Parent
//and check if type for both tables are the same, like myISAM or innoDB, etc
//Other aspects to check with this error message: the columns used as foreign
keys must be indexed, they must be of the same type
(if i.e one is of type smallint(5) and the other of type smallint(6),
it won't work), and, if they are integers, they should be unsigned.
//or check for charsets
show variables like "character_set_database";
show variables like "collation_database";
//edited: try something like this
ALTER TABLE table2
ADD CONSTRAINT fk_IdTable2
FOREIGN KEY (Table1_Id)
REFERENCES Table1(Table1_Id)
ON UPDATE CASCADE
ON DELETE CASCADE;

I lost for hours for that!
PK in one table was utf8 in other was utf8_unicode_ci!

thanks S Doerin:
"Just for completion.
This error might be as well the case if you have a foreign key with VARCHAR(..) and the charset of the referenced table is different from the table referencing it.
e.g. VARCHAR(50) in a Latin1 Table is different than the VARCHAR(50) in a UTF8 Table."
i solved this problem, changing the type of characters of the table.
the creation have latin1 and the correct is utf8.
add the next line.
DEFAULT CHARACTER SET = utf8;

I had the same problems.
The issue is the reference column is not a primary key.
Make it a primary key and problem is solved.

My case was that I had a typo on the referred column:
MariaDB [blog]> alter table t_user add FOREIGN KEY ( country_code ) REFERENCES t_country ( coutry_code );
ERROR 1005 (HY000): Can't create table `blog`.`t_user` (errno: 150 "Foreign key constraint is incorrectly formed")
The error message is quite cryptic and I've tried everything - verifying the types of the columns, collations, engines, etc.
It took me awhile to note the typo and after fixing it all worked fine:
MariaDB [blog]> alter table t_user add FOREIGN KEY ( country_code ) REFERENCES t_country ( country_code );
Query OK, 2 rows affected (0.039 sec)
Records: 2 Duplicates: 0 Warnings: 0

I face this problem the error came when you put the primary key in different data type like:
table 1:
Schema::create('products', function (Blueprint $table) {
$table->increments('id');
$table->string('product_name');
});
table 2:
Schema::create('brands', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('brand_name');
});
the data type for id of the second table must be increments

For anyone struggling as I was with this issue, this was my problem:
I was trying to alter a table to change a field from VARCHAR(16) to VARCHAR(255) and this was referencing another table column where the datatype was still VARCHAR(16)...

I had the same issue with Symfony 2.8.
I didn't get it at first, because there were no similar problems with int length of foreign keys etc.
Finally I had to do the following in the project folder. (A server restart didn't help!)
app/console doctrine:cache:clear-metadata
app/console doctrine:cache:clear-query
app/console doctrine:cache:clear-result

I was using HeidiSQL and to solve this problem I had to create an index in the referenced table with all the columns being referenced.

I had issues using Alter table to add a foreign key between two tables and the thing that helped me was making sure each column that I was trying to add a foreign key relationship to was indexed. To do this in PHP myAdmin:
Go to the table and click on the structure tab.
Click the index option to index the desired column as shown in screenshot:
Once I indexed both columns I was trying to reference with my foreign keys, I was able to successfully use the alter table and create the foreign key relationship. You will see that the columns are indexed like in the below screenshot:
notice how zip_code shows up in both tables.

I ran into the same issue just now. In my case, all I had to do is to make sure that the table I am referencing in the foreign key must be created prior to the current table (earlier in the code). So if you are referencing a variable (x*5) the system should know what x is (x must be declared in earlier lines of code). This resolved my issue, hope it'll help someone else.

The problem is very simple to solve
e.g: you have two table with names users and posts and you want create foreign key in posts table and you use phpMyAdmin
1) in post table add new column
(name:use_id | type: like the id in user table | Length:like the id in user table | Default:NULL | Attributes:unsigned | index:INDEX )
2)on Structure tab go to relation view
(Constraint name: auto set by phpmyAdmin | column name:select user_id |table:users | key: id ,...)
It was simply solved
javad mosavi iran/urmia

I had the same error, and I discovered that on my own case, one table was MyISAM, and the other one INNO. Once I switched the MyISAM table to INNO. It solved the issue.

One more solution which I was missing here is, that each primary key of the referenced table should have an entry with a foreign key in the table where the constraint is created.

If U Table Is Myisum And New Table Is InoDb you Are Note Foreign
You Must Change MyIsum Table To InoDb

Rename Primary Key constraint on MySQL

I think this might be a bug with MySQL, but I'm not sure. Anyone can tell me how can I create a primary key for a table and then rename the primary constraint? If possible already create the primary key during table creation with the desired name.
All primary keys I create end up with the name "Primary". Already tried creating an index with the desired name before adding the PK, and renaming the PK using MySQL Workbench. None of them worked.
Anybody have any idea what's wrong and why can't I rename the PK name?
Thanks!

I'm not sure that MySQL allows to give names to primary keys in the first place. While there appears to be a syntax for it:
CREATE TABLE test (
test_id INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
CONSTRAINT my_test_pk PRIMARY KEY (test_id)
)
ENGINE=InnoDB;
... it doesn't show up in information_schema.TABLE_CONSTRAINTS or any other place I could spot so I have the impression that it's simply silently discarded.
The name you see is probably a hard-coded name your GUI client gives to all primary keys.
Edit: here's a quote from the manual:
The name of a PRIMARY KEY is always PRIMARY, which thus cannot be
used as the name for any other kind of index.

unwanted primary keys in a new sql table

I have bulid a new table in my SQL database with the following command :
Create Table if not exists Images (ImageID int (10) primary key NOT NULL AUTO_INCREMENT ,
UserID int (10) NOT NULL,
Translated tinyint Default 0,
DeleteImage tinyint Default 0,
DataPosted date,
TheImage blob,
Translation text,
FOREIGN KEY (UserID) REFERENCES Users(UserID) ON DELETE CASCADE)
the table is been created just fine, but what i'm checking what was build i've found out that in the table the columns ImageID, TheImage, and Translation are defined as primary keys.
as the query is showing I want only the ImageId to be the primary key.
what's happening here?
tnx

Seems quite unlikely. It seems far more likely that something is wrong with whatever tool you're using to find out which columns are primary keys.
Actually, from the documentation - here: http://dev.mysql.com/doc/refman/5.1/en/create-table.html - it would follow that a MySQL table can only have one primary key. But even if not, why would you worry about it?

mysql Foreign key constraint is incorrectly formed error

I have two tables, table1 is the parent table with a column ID and table2 with a column IDFromTable1 (not the actual name) when I put a FK on IDFromTable1 to ID in table1 I get the error Foreign key constraint is incorrectly formed error. I would like to delete table 2 record if table1 record gets deleted. Thanks for any help
ALTER TABLE `table2`
ADD CONSTRAINT `FK1`
FOREIGN KEY (`IDFromTable1`) REFERENCES `table1` (`ID`)
ON UPDATE CASCADE
ON DELETE CASCADE;
Let me know if any other information is needed. I am new to mysql

I ran into this same problem with HeidiSQL. The error you receive is very cryptic. My problem ended up being that the foreign key column and the referencing column were not of the same type or length.
The foreign key column was SMALLINT(5) UNSIGNED and the referenced column was INT(10) UNSIGNED. Once I made them both the same exact type, the foreign key creation worked perfectly.

For anyone facing this problem, just run
SHOW ENGINE INNODB STATUS
and see the LATEST FOREIGN KEY ERROR section for details.

I had the same problem when the parent table was created using MyISAM engine. It's a silly mistake, which I fixed with:
ALTER TABLE parent_table ENGINE=InnoDB;

make sure columns are identical(of same type) and if reference column is not primary_key, make sure it is INDEXED.

Syntax for defining foreign keys is very forgiving, but for anyone else tripping up on this, the fact that foreign keys must be "of the same type" applies even to collation, not just data type and length and bit signing.
Not that you'd mix collation in your model (would you?) but if you do, be sure your primary and foreign key fields are of the same collation type in phpmyadmin or Heidi SQL or whatever you use.
Hope this saves you the four hours of trial and error it cost me.

I had same problem, but solved it.
Just make sure that column 'ID' in 'table1' has UNIQUE index!
And of course the type, length of columns 'ID' and 'IDFromTable1' in these two tables has to be same. But you already know about this.

mysql error texts doesn't help so much, in my case, the column had "not null" constraint, so the "on delete set null" was not allowed

Just for completion.
This error might be as well the case if you have a foreign key with VARCHAR(..) and the charset of the referenced table is different from the table referencing it.
e.g. VARCHAR(50) in a Latin1 Table is different than the VARCHAR(50) in a UTF8 Table.

One more probable cause for the display of this error. The order in which I was creating tables was wrong. I was trying to reference a key from a table that was not yet created.

I had the same issue, both columns were INT(11) NOT NULL but I wan't able to create the foreign key.
I had to disable foreign keys checks to run it successfully :
SET FOREIGN_KEY_CHECKS=OFF;
ALTER TABLE ... ADD CONSTRAINT ...
SET FOREIGN_KEY_CHECKS=ON;
Hope this helps someone.

if everything is ok, just add ->unsigned(); at the end of foregin key.
if it does not work, check the datatype of both fields. they must be the same.

(Last Resent) Even if the field name and data type is the same but the collation is not the same, it will also result to that problem.
For Example
TBL
NAME | DATA
TYPE |
COLLATION
ActivityID | INT |
latin1_general_ci
ActivityID | INT |
utf8_general_ci
Try Changing it into
TBL
NAME | DATA
TYPE |
COLLATION
ActivityID | INT |
latin1_general_ci
ActivityID | INT |
latin1_general_ci
....
This worked for me.

This problem also occur in Laravel when you have the foreign key table table1 migration after the migration in which you reference it table2.
You have to preserve the order of the migration in order to foreign key feature to work properly.
database/migrations/2020_01_01_00001_create_table2_table.php
database/migrations/2020_01_01_00002_create_table1_table.php
should be:
database/migrations/2020_01_01_00001_create_table1_table.php
database/migrations/2020_01_01_00002_create_table2_table.php

Check the tables engine, both tables have to be the same engine, that helped me so much.

Although the other answers are quite helpful, just wanted to share my experience as well.
I faced the issue when I had deleted a table whose id was already being referenced as foreign key in other tables (with data) and tried to recreate/import the table with some additional columns.
The query for recreation (generated in phpMyAdmin) looked like the following:
CREATE TABLE `the_table` (
`id` int(11) NOT NULL, /* No PRIMARY KEY index */
`name` varchar(255) NOT NULL,
`name_fa` varchar(255) NOT NULL,
`name_pa` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
... /* SOME DATA DUMP OPERATION */
ALTER TABLE `the_table`
ADD PRIMARY KEY (`id`), /* PRIMARY KEY INDEX */
ADD UNIQUE KEY `uk_acu_donor_name` (`name`);
As you may notice, the PRIMARY KEY index was set after the creation (and insertion of data) which was causing the problem.
Solution
The solution was to add the PRIMARY KEY index on table definition query for the id which was being referenced as foreign key, while also removing it from the ALTER TABLE part where indexes were being set:
CREATE TABLE `the_table` (
`id` int(11) NOT NULL PRIMARY KEY, /* <<== PRIMARY KEY INDEX ON CREATION */
`name` varchar(255) NOT NULL,
`name_fa` varchar(255) NOT NULL,
`name_pa` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Try running following:
show create table Parent
//and check if type for both tables are the same, like myISAM or innoDB, etc
//Other aspects to check with this error message: the columns used as foreign
keys must be indexed, they must be of the same type
(if i.e one is of type smallint(5) and the other of type smallint(6),
it won't work), and, if they are integers, they should be unsigned.
//or check for charsets
show variables like "character_set_database";
show variables like "collation_database";
//edited: try something like this
ALTER TABLE table2
ADD CONSTRAINT fk_IdTable2
FOREIGN KEY (Table1_Id)
REFERENCES Table1(Table1_Id)
ON UPDATE CASCADE
ON DELETE CASCADE;

I lost for hours for that!
PK in one table was utf8 in other was utf8_unicode_ci!

thanks S Doerin:
"Just for completion.
This error might be as well the case if you have a foreign key with VARCHAR(..) and the charset of the referenced table is different from the table referencing it.
e.g. VARCHAR(50) in a Latin1 Table is different than the VARCHAR(50) in a UTF8 Table."
i solved this problem, changing the type of characters of the table.
the creation have latin1 and the correct is utf8.
add the next line.
DEFAULT CHARACTER SET = utf8;

I had the same problems.
The issue is the reference column is not a primary key.
Make it a primary key and problem is solved.

My case was that I had a typo on the referred column:
MariaDB [blog]> alter table t_user add FOREIGN KEY ( country_code ) REFERENCES t_country ( coutry_code );
ERROR 1005 (HY000): Can't create table `blog`.`t_user` (errno: 150 "Foreign key constraint is incorrectly formed")
The error message is quite cryptic and I've tried everything - verifying the types of the columns, collations, engines, etc.
It took me awhile to note the typo and after fixing it all worked fine:
MariaDB [blog]> alter table t_user add FOREIGN KEY ( country_code ) REFERENCES t_country ( country_code );
Query OK, 2 rows affected (0.039 sec)
Records: 2 Duplicates: 0 Warnings: 0

I face this problem the error came when you put the primary key in different data type like:
table 1:
Schema::create('products', function (Blueprint $table) {
$table->increments('id');
$table->string('product_name');
});
table 2:
Schema::create('brands', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('brand_name');
});
the data type for id of the second table must be increments

For anyone struggling as I was with this issue, this was my problem:
I was trying to alter a table to change a field from VARCHAR(16) to VARCHAR(255) and this was referencing another table column where the datatype was still VARCHAR(16)...

I had the same issue with Symfony 2.8.
I didn't get it at first, because there were no similar problems with int length of foreign keys etc.
Finally I had to do the following in the project folder. (A server restart didn't help!)
app/console doctrine:cache:clear-metadata
app/console doctrine:cache:clear-query
app/console doctrine:cache:clear-result

I was using HeidiSQL and to solve this problem I had to create an index in the referenced table with all the columns being referenced.

I had issues using Alter table to add a foreign key between two tables and the thing that helped me was making sure each column that I was trying to add a foreign key relationship to was indexed. To do this in PHP myAdmin:
Go to the table and click on the structure tab.
Click the index option to index the desired column as shown in screenshot:
Once I indexed both columns I was trying to reference with my foreign keys, I was able to successfully use the alter table and create the foreign key relationship. You will see that the columns are indexed like in the below screenshot:
notice how zip_code shows up in both tables.

I ran into the same issue just now. In my case, all I had to do is to make sure that the table I am referencing in the foreign key must be created prior to the current table (earlier in the code). So if you are referencing a variable (x*5) the system should know what x is (x must be declared in earlier lines of code). This resolved my issue, hope it'll help someone else.

The problem is very simple to solve
e.g: you have two table with names users and posts and you want create foreign key in posts table and you use phpMyAdmin
1) in post table add new column
(name:use_id | type: like the id in user table | Length:like the id in user table | Default:NULL | Attributes:unsigned | index:INDEX )
2)on Structure tab go to relation view
(Constraint name: auto set by phpmyAdmin | column name:select user_id |table:users | key: id ,...)
It was simply solved
javad mosavi iran/urmia

I had the same error, and I discovered that on my own case, one table was MyISAM, and the other one INNO. Once I switched the MyISAM table to INNO. It solved the issue.

One more solution which I was missing here is, that each primary key of the referenced table should have an entry with a foreign key in the table where the constraint is created.

If U Table Is Myisum And New Table Is InoDb you Are Note Foreign
You Must Change MyIsum Table To InoDb