Trying to add foreign key in mysql with heidisql - foreign-keys

I've been trying to add a foreign key to my table using heidisql and I keep getting the error 1452.
After reading around I made sure all my tables were running on InnoDB as well as checking that they had the same datatype and the only way I can add my key is if I drop all my data which I don't intend to do since I have spent quite a few hours on this.
here is my table create code:
CREATE TABLE `data` (
`ID` INT(10) NOT NULL AUTO_INCREMENT,
#bunch of random other columns stripped out
`Ability_1` SMALLINT(5) UNSIGNED NOT NULL DEFAULT '0',
#more stripped tables
`Extra_Info` SET('1','2','3','Final','Legendary') NOT NULL DEFAULT '1' COLLATE 'utf8_unicode_ci',
PRIMARY KEY (`ID`),
UNIQUE INDEX `ID` (`ID`)
)
COLLATE='utf8_unicode_ci'
ENGINE=InnoDB
AUTO_INCREMENT=650;
here is table 2
CREATE TABLE `ability` (
`ability_ID` SMALLINT(5) UNSIGNED NOT NULL AUTO_INCREMENT,
#stripped columns
`Name_English` VARCHAR(12) NOT NULL COLLATE 'utf8_unicode_ci',
PRIMARY KEY (`ability_ID`),
UNIQUE INDEX `ability_ID` (`ability_ID`)
)
COLLATE='utf8_unicode_ci'
ENGINE=InnoDB
AUTO_INCREMENT=165;
Finally here is the create code along with the error.
ALTER TABLE `data`
ADD CONSTRAINT `Ability_1` FOREIGN KEY (`Ability_1`) REFERENCES `ability` (`ability_ID`) ON UPDATE CASCADE ON DELETE CASCADE;
/* SQL Error (1452): Cannot add or update a child row: a foreign key constraint fails (`check`.`#sql-ec0_2`, CONSTRAINT `Ability_1` FOREIGN KEY (`Ability_1`) REFERENCES `ability` (`ability_ID`) ON DELETE CASCADE ON UPDATE CASCADE) */
If there is anything else I can provide please let me know this is really bothering me. I'm also using 5.5.27 - MySQL Community Server (GPL) that came with xampp installer.

If you are using HeidiSQL it is pretty easy.
Just see the image, click on the +Add to add foreign keys.
I prefer GUI way of creating tables and its attribute because it saves time and reduces errors.

I found it. Sorry everyone. The problem was that I had 0 as a default value for my fields while my original table had no value for 0.

Here is how you can do it ;
Create your Primary keys. For me this was straight forward so I won't post how to do that here
To create your FOREIGN KEYS you need to change the table / engine type for each table from MyIASM to InnoDb. To do this Select the table on the right hand side then select the OPTIONS tab on the right hand side and change the engine from MyIASM to InnoDb for every table.

Related

Oracle APEX 21.2.0 display image Primary Key

I want to display image in report column. My table has composite primary key: ID and DATE.
When I add these columns in BLOB attributes as Primary Key Column 1 and Primary Key Column 2 report can not find data because of DATE column. Is it a problem in date format, or something else?
I'd suggest you to use only one column as a primary key column (a sequence or - if your database version supports it - an identity column).
Combination of [ID, DATE] you currently have can then be set to unique key (set both columns NOT NULL to "mimic" what primary key would do).
Why? Although your data model probably is just fine, certain Apex functionalities "suffer" from such things and prefer having a single-column primary keys.

Why MySQL workbench is making all my foreign keys unique?

I've created a MySQL Model with a few tables, some of them with fk's to another table. I usually export the SQL from MySQL Model to my database using the "Forward Engineer SQL CREATE Script" inside File -> Export -> Forward Engineer SQL CREATE Script. The problem here is that when I generate the creation script, all my fk's become unique. I didn't check UQ option in MySQL Model but it creates a script with unique fk's anyway, so, I need to change the SQL file generated and remove all the unwanted uniques. Anyone has a clue why this is happening?
Generated script:
CREATE TABLE IF NOT EXISTS `u514786799_detranleiloes`.`Lotes` (
`createdAt` DATE NOT NULL,
`updatedAt` DATE NOT NULL,
`id` INT UNIQUE NOT NULL AUTO_INCREMENT,
`LeiloesId` INT UNIQUE NOT NULL,
`conservado` TINYINT NULL,
`numero` INT NOT NULL,
`CRDsId` INT UNIQUE NULL,
PRIMARY KEY (`id`),
INDEX `fk_Lotes_Leiloes_idx` (`LeiloesId` ASC),
INDEX `fk_Lotes_CRDs1_idx` (`CRDsId` ASC),
CONSTRAINT `fk_Lotes_Leiloes`
FOREIGN KEY (`LeiloesId`)
REFERENCES `u514786799_detranleiloes`.`Leiloes` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_Lotes_CRDs1`
FOREIGN KEY (`CRDsId`)
REFERENCES `u514786799_detranleiloes`.`CRDs` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
AUTO_INCREMENT = 1;

Error Key (user_id)=(1) is not present in table "auth_user" when migrating

I am running into this error when i migrate.Is there any way to save data on my database.I know that dropping the auth_user table will fix the issue. I am running postgresql.
Thanks!
FATAL ERROR - The following SQL query failed: ALTER TABLE "api_poi" ADD CONSTRAINT "user_id_refs_id_20f256ff" FOREIGN KEY ("user_id") REFERENCES "auth_user" ("id") DEFERRABLE INITIALLY DEFERRED;
The error was: insert or update on table "api_poi" violates foreign key constraint "user_id_refs_id_20f256ff"
DETAIL: Key (user_id)=(1) is not present in table "auth_user".
There is a row in api_poi which has user_id set to 1, but there is no row in auth_user which has id set to 1.
So it is impossible to define a foreign key constraint like you are trying to do.
You will have to add rows to auth_user or remove rows from api_poi until the foreign key constraint is satisfied.
Include 'django.contrib.admin', in your INSTALLED_APP, then run migrations and migrate again.
I too had the very hardship. However, I had to flush all the data recorded in the database to avert this error as I didn't find any of the solutions given above helpful.
$ python manage.py flush
And confirmed yes.
I certainly would not recommend this way of bypassing integrity error if you care about the existing data in your DB coz it will nullify the table by omitting all the data outta the table.
go to the database and insert code
ALTER SEQUENCE TableName_id_seq RESTART WITH 'last id number';
for example :
ALTER SEQUENCE account_id_seq RESTART WITH 100;

coding many to many relationship in c++ sqlite3

I trying to code a many to many relationship in c++ sqlite3.
in the diagram below,
managers can add many job opportunities.
jobs opportunities is being add by many managers
my create table statements
"CREATE TABLE Manager(" \
"manager_id INTEGER PRIMARY KEY NOT NULL,"\
"name varchar(45) NOT NULL);"
"CREATE TABLE jobs ("
"jobId INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"\
"jobTitle varchar(45) NOT NULL);"
"CREATE TABLE Add ("
"manager_id,jobId INTEGER PRIMARY KEY NOT NULL,"\
"date varchar(45) NOT NULL,"\
"FOREIGN KEY(manager_id) REFERENCES Manager(manager_id),"\
"FOREIGN KEY(job_id) REFERENCES jobs(job_id));";
my manager table is populated with the following information
1|john
2|bob
let's say manager john has added two jobs,jobTitle jobA and jobB
then my insert statement code will look like this.http://pastebin.com/0E8CzPgX
then my jobs tables is populated with the following information
1|jobA
2|jobB
the final step is to take the id of john(manager id = 1) and the two jobsId(1,2) and add it inside
the add table. I don't have an idea of how should I code
so that the add table will become like this.
add table
manager_id|job_id|date
1 | 1 |30-01-2014
1 | 2 |30-01-2014
please advise.thanks
Do you mean something like
sql = "INSERT INTO Add(manager_id,jobId,date) VALUES (?,?,?);";
?
Your problem seems to be that you defined jobID to be the primary key of the table Add, which you don't need.
jobId INTEGER PRIMARY KEY NOT NUL
A common approach to many-to-many relations in a database is to include an intermediate table.
This intermediate table (let's call it Manager_jobs) would have at least 2 columns, both referring to other tables via foreign key. The first attribute would be the primary key of Manager, the second one the primary key of jobs.
Each time you add a job, you just add an entry to Manager_jobs with the foreign keys respectively.
So, Manager_jobs would look like this:
ManagerID | JobID
==========|======
4 | 2
3 | 2
4 | 1
As you can see, Manager_jobs can encode that a Manager has multiple jobs assigned and vice versa.
This approach, of course, requires you to have some form of primary key for both data tables.

Can't create table (errno: 150) InnoDB adding foreign key constraints

Really hate to use other people's time, but it seems the problem is just not going away.
I considered all recommendations at http://verysimple.com/2006/10/22/mysql-error-number-1005-cant-create-table-mydbsql-328_45frm-errno-150/ and at http://forums.mysql.com/read.php?22,19755,19755#msg-19755 but nothing.
hope that someone points to a stupid mistake.
here are the tables:
CREATE TABLE IF NOT EXISTS `shop`.`category` (
`id` INT(11) NOT NULL AUTO_INCREMENT ,
`category_id` INT(11) NOT NULL ,
`parent_id` INT(11) NULL DEFAULT '0' ,
`lang_id` INT(11) NOT NULL ,
...other columns...
PRIMARY KEY (`id`, `category_id`) )
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_unicode_ci;
CREATE TABLE IF NOT EXISTS `shop`.`product_category` (
`category_id` INT(11) NOT NULL ,
`product_id` INT(11) NOT NULL ,
INDEX `fk_product_category_category1_zxc` (`category_id` ASC) ,
CONSTRAINT `fk_product_category_category1_zxc`
FOREIGN KEY (`category_id` )
REFERENCES `shop`.`category` (`category_id` )
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_unicode_ci;
Error Code: 1005. Can't create table 'shop.product_category' (errno: 150)
You need an index on category_id in the category table (I see it's part of the primary key, but since it's the second column in the index, it can not be used). The field you are referencing in a foreign key always should be indexed.
In my case the issue was more like what was described in the first article you've linked to.
So I just had to make sure that:
Referenced Column is an index,
both Referencing Column and Referenced Column share the same type and length, i.e. e.g. both are INT(10),
both share the same not null, unsigned, zerofill etc. configuration.
both tables are InnoDB!
Here's the query template where Referencing Column is referencing_id and Referenced Column is referenced_id:
ALTER TABLE `db`.`referencing`
ADD CONSTRAINT `my_fk_idx`
FOREIGN KEY (`referencing_id`)
REFERENCES `db`.`referenced`(`referenced_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION;
Update 2016-03-13: Ran into this problem again, ended up finding my own answer. This time it didn't help though. Turns out the other table was still set to MyISAM, as soon as I changed it to InnoDB everything worked.