A type of integrity constraint used in a RDBMS platform to ensure that a value in a column matches one of a range of key values from another table.

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529 views

Merging Results while avoiding Key Constraint Error?

I have a table with a primary key which is two integer fields, each a foreign key to a different table. (Multi to Multi table) In one of the foreign tables two rows are merged and this table is ...
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1answer
10 views

Aruba-MySQL: can't create/change table to engine=INNODB

We have our database stored in aruba (mysql.aruba.it) where there is a table called "task". Because of many changes in the requirements we decided to drop the table and create it again from 0 with ...
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2answers
34 views

MySQL - Creating an associative table

I have the following table structures: Cases: (PK) case_id | case_notes | time 1 | blah | timestamp 2 | blah | timestamp 3 | blah | timestamp . | . ...
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1answer
137 views

ON DELETE CASCADE not deleting entry for foreign key

I am running the below query in ideone CREATE TABLE AUTHOR ( AUTHOR_ID NUMBER(5) PRIMARY KEY, AUTHOR_NAME VARCHAR2(18) ); INSERT INTO AUTHOR (AUTHOR_ID, AUTHOR_NAME) VALUES (1234, 'MC GRAW HILL'); ...
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1answer
224 views

adding autoincrement to id already part of foreign key

I would like to add the autoincrement property for all my table's columns named id in a schema. However, most of them are part of a foreign key constraint. Is there any other way to do it without ...
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2answers
312 views

insert inserted id to another table

Here's the scenario: create table a ( id serial primary key, val text ); create table b ( id serial primary key, a_id integer references a(id) ); create rule a_inserted as on insert to a do ...
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1answer
41 views

can I use many-to-many relation with weak entity

I have an entity, for example employee(key employee ID), and every employee can have multiple responsibilities. Every responsibility can be tasked to multiple employees. I have 3 options: 1) Create ...
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1answer
119 views

Can I use `on delete set null` on a compound foreign key which contains a primary key column?

The docs say: Restricting and cascading deletes are the two most common options. RESTRICT prevents deletion of a referenced row. NO ACTION means that if any referencing rows still exist when the ...
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1answer
88 views

MySQL #1005 - Can't create table 'startet' (errno: 150)

Can anyone figure out why phpMyAdmin won't create the last table? It works fine if I drop the last foreign key, but I need it in there to get my assignment approved... CREATE TABLE nasjon ( ...
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1answer
38 views

multi-column FKs with NULL values

I understand that in PostgreSQL if there is a multi-column FK from table B to table A and one or more of the FK columns in table B are nullable then the FK is still considered as "honored" for the ...
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1answer
131 views

create foreign keys for pivot tables

I'm trying to optimise and speed up a mysql 5.6 datatabase. I have two tables with a many to many relationship: Reservation and Resource. Each Reservation can have many Resources and each Resource ...
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3answers
396 views

Mysql Create table shows ERROR 1005 errno 150

I am trying to make a junction table, but I getting a ERROR 1005 errno 150 CREATE TABLE 61furiousFistPokemon( cardNumber int NOT NULL PRIMARY KEY, pokemonName VARCHAR(12), type VARCHAR(10), stage ...
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1answer
56 views

Query executes fast, but keeps the table locked for some time

Executing the following query is very fast (75ms), but removing the comment from the last row it becomes slow (2.5s), and the time increases exponentially with the number of rows in the table. It ...
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1answer
61 views

Save dataset within another table best practice

I want to save one dataset within another table, this dataset should be persistent. For example Table1: FIELDS (A,B,C) Table2: FIELDS (D, DuplicateTable1) I can think of 2 possiblities: Have ...
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1answer
135 views

Implementing a simple ERD in MySQL: is the implementation below 100% compliant with the ERD?

ERD Consider the following ERD: Tables From it, I derived the following tables: Company ------------------ c_id c_name ------------------ CompanyEmail ------------------ c_id ...
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1answer
37 views

Insert / Edit Rows by Selecting FK row

When inserting or editing rows ("Edit Top 200 Rows") for a table with a FK constraint, can the editor be configured to select the foreign row, rather than me having to look up the FK?
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2answers
73 views

MySQL foreign key error

I need to update rows in a child table,but I am getting following error while I run the code, Company Table CREATE TABLE `company` ( `Company_id` int(11) NOT NULL AUTO_INCREMENT, `Company_name` ...
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1answer
317 views

Can a foreign key have a default value equal to 0?

I have a column whose default value is 0 .Can I make that column as foreign_key
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1answer
385 views

Mysql foreign key cascade delete

Does mysql have a way to delete all sub links if a row was deleted from a "parent" table? Example table setup is below, the issue I am trying to avoid is having to maintain a script that deletes the ...
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2answers
58 views

Guaranteeing a FK relationship through multiple tables

I'm using MySQL / InnoDB, and using foreign keys to preserve relationships across tables. In the following scenaro (depicted below), a 'manager' is associated with a 'recordLabel', and an 'artist' is ...
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1answer
103 views

Foreign key in MySQL

I am learning about database, I need to know something about the foreign key in MySQL. Consider the following two tables. UserGroupType. UserGroup. UserGroupType: UserGroup: In this table ...
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1answer
984 views

HOW to “SUM” and “JOIN” for single query of a poll results?

I have a poll database as CREATE TABLE poll_answer answer_id, answer varchar(255), poll_id int(11), FOREIGN KEY(poll_id) REFERENCES polls(poll_id) ON DELETE CASCADE, PRIMARY KEY(answer_id) ) ...
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2answers
969 views

MySQL cannot create foreign key, errors 1005, 150

I'm trying to add a foreign key to a MySQL InnoDB table, linking a BIGINT with a table within the same database. I'm using MySQL Workbench to do this. It generates a script: ALTER TABLE ...
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1answer
74 views

best relationship for this design?

There is a table users with autoincrement primary key id. There is also a table employees (every employee is a user but not vice versa). The employees primary key is userid. The field userid is not ...
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1answer
636 views

Retrieving all PK and FK

I have a big database that I need to extract all primary keys and foreign keys from each table. I have pgAdmin III. Is there a way to do this automatically and not go over each table manually?
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1answer
65 views

Check for records that break a foreign constraint (created with foreign_key_checks = 0)?

Is there an easy way to check for any records in a table that breaks any constraint? The constraint was created on a populated table using "foreign_key_checks=0".
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1answer
7k views

To drop a table, do I have to drop all foreign key constraints or can I just NOCHECK them?

I know you cannot drop a table that has active foreign key constraints. So I was wondering is it safe to: ALTER TABLE myTable NOCHECK CONSTRAINT all DROP TABLE myTable Rather than dropping the ...
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1answer
631 views

Modify MySQL foreign key related column without dropping foreign key relation

I need to modify a foreign key related column. When I tried to alter it I got "Error on rename of 'x' to 'y' (errno: 150)" error. So I googled and found foreign key relation is the 'villain'. I ...
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1answer
108 views

Is it acceptable to have a surrogate/primary key of one table be the primary/foreign key of another table?

For my purposes I'm trying to apply this to Microsoft SQL, but would like to know if there are restrictions for other DBMS regarding this. I don't know how to represent UML as ascii characters so if ...
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1answer
156 views

Handling error of foreign key

How to set a FK value NULL upon receiving error for foreign key constraint? Consider a simple table a CREATE TABLE test ( id int(11) NOT NULL AUTO_INCREMENT ex_key int(11), FOREIGN ...
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2answers
2k views

Query PostgreSQL 9.0 table on foreign key value?

Noob-type question: Say I have two tables, candies and colors. The colors table holds just code/value pairs like 01 yellow, 02 blue, 03 green, etc. and is referenced in the candies table by code. ...
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29 views

What order do foreign key constraints run in? Why does my foreign key not work after import?

I have two tables tags and tag_memberships in a PostgreSQL database. On the tag_memberships table, I have two constraints. The first is this: ALTER TABLE tag_memberships ADD CONSTRAINT ...
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2answers
31 views

Performance impact of adding a foreign key to a 1M rows table

I have an ecommerce database running MariaDB + InnoDB, which has a table to store the transactions (T) and another which stores quotes (Q). I'd like to make a connection between T and Q by adding a ...
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12 views

Sybase: Delete foreign key IF exists fails

I've a database, on which we will have to delete of tables/foreign keys/view. We did deleted all the required element in PowerDesigner, then we did the "Apply model change to the database". We ...
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0answers
16 views

Part of composite foreign keys as primary key

I have a table A with a,b,c as primary key. Table B reference has a,b,c as foreign keys and it wants to set its own column d and foreign key a as primary key, Is it legal? Or does it have to set the ...
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0answers
19 views

Synchronization of DB

I have 2 databases and I need to synchronize data between them. I need to delete all the data from DB1 and then insert data to DB1 from DB2. What solution will you suggest drop all the foreign ...
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1answer
18 views

insert error foreign key permission

I have a problem with permissions, and I don't find where I messed up (v 9.4) I have a database DB1 owned by Bill, with 2 schemas pat and tom. Both schemas are identical , pat is owned by pat, tom by ...
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0answers
53 views

Deadlocks due to foreign keys (MySQL)

We are in the process of creating a web application using mysql as a data source. We are using spring with hibernate as an ORM framework. We have hundreds of entities with relations (manyToMany \ ...
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0answers
39 views

Cleaning up orphaned metadata in information_schema

OK - so the server (Percona 5.6 in this case) 'went away' in the middle of declaring a constraint like so: alter table mytable add constraint fk_mytable_myothertable foreign key (myothertable_id) ...
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2answers
65 views

In mysql, find all instances of a named column that are not foreign keys

This one has had me trumped for a while! I want to run a query to retrieve all instances of a column (from information_schema, I guess) that ARE or ARE NOT foreign keys. Now, let me back of a little ...
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1answer
46 views

How to enforce that one row in a parent table MUST be associated with at least a row in a child table [duplicate]

I have a one to many relationship enforced via FK, classic example order and order_item, whereby a fk on the order_item to the order table enforces that one item belongs to one order, and one order ...
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0answers
15 views

Does foreign key and cascade take advantage of filtered index?

I have a table T2 referencing another table T1 The referring column ref_T1 has a nonclustered unique index on it, filtered for value <> 0 When I delete a few rows from T1 and the forein key ...
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208 views

SQL Error 1452 : Cannot add or update a child row: a foreign key constraint fails

I am trying to install Zabbix by following this guide. I ran into the following problems when trying to run data.sql after running scheme.sql successfully mysql -D zabbix -uzabbix -pPassword < ...
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0answers
19 views

Postgres: Migrate data with FKs to multi-database

I currently have a single DB with data from a number of clients. I have been tasked with writing a script that splits the data up into separate DBs per client (each DB will have the same schema). For ...
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1answer
43 views

can't create foreign key in sqlite

I'm trying to run this code in sqlite: sqlite> CREATE TABLE test(id integer primary key AUTOINCREMENT, page varchar(10), dp_record_id integer, foreign key (webserver_id) REFERENCES ...
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26 views

Foreign keys in MySQL Workbench

I am defining an EER model in MySQL Workbench. I have a library with multiple copies of each book and each book has its location in the library listed in the system. When I'm creating one-to-many ...
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43 views

Indexing on cached data from related table using triggers — Is there a better way?

Edit: Schema details per request from Aaron Betrand -- I'll break the schema down to the relevant fields of the two tables. Orders (ID int IDENTITY, Status char(1)) Services(OrderID FOREIGN KEY ...
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37 views

Forcing FK constraint to validated in system catalog

I have a big table (~60gigs, 35mill+ rows) that I need to add a FK to. Adding a FK directly to the table causes a validation which runs for about 30secs that I want avoid as it's a 30sec access ...
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1answer
139 views

How to temporarily disable foreign keys in Amazon RDS PostgreSQL?

I'm migrating existing test environment to Amazon RDS PostgreSQL. The test framework has a feature of reloading data in certain tables to an earlier state. For this it disables foreign keys, deletes ...
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66 views

Allow only parent DELETE cascade to delete child rows

I have a Product database with the following components: ProductOptions is a list of option names for each Product, ProductVariants is a list of variants for each Product and ProductVariantOptions is ...