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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Foreign key default value

I have a master table and another table with foreign key. I can easily add data to master table. But whenever I want to add data to the connected table, I get a message saying Foreign key doesn't have ...
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2answers
16k views

PostgreSQL - insert/update violates foreign key constraints

I am a new one in postgreSQL. I have 3 tables, one table references the other 2 table's primary keys. But I couldn't insert data into the Table3. See the code below : DROP TABLE Table1 CASCADE; ...
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1answer
161 views

Overcome MERGE JOIN(INDEX SCAN) with explicit single KEY value on a FOREIGN KEY

Added 7/11 The issue is deadlocks occur because of index scan during MERGE JOIN. In this case a transaction trying to get S lock on the whole index at the FK parent table, but previously another ...
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3answers
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How do I insert a row which contains a foreign key?

Using PostgreSQL v9.1. I have the following tables: CREATE TABLE foo ( id BIGSERIAL NOT NULL UNIQUE PRIMARY KEY, type VARCHAR(60) NOT NULL UNIQUE ); CREATE TABLE bar ( id BIGSERIAL ...
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1answer
89 views

Rename PK column names when they are FK in another tables

I need to change the names on PK columns and that has relations with another tables meaning they are FK also so this is what I am doing: SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0; SET ...
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266 views

Can't add a foreign key constraint in a table on Postgresql

I'm trying to add a foreign key of "prefectures" table in "centresdevote" table. But I'm having this error while trying to add a foreign key to "centresdevote" table. I had no problem adding foreign ...
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2answers
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What does 'ibfk' stand for in MySQL?

If I create a foreign key constraint for table 'photos' in phpmyadmin, I later see that the constraint is named 'photos_ibfk_1', and the next constraint is called 'photos_ibfk_2', etc. From this I ...
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1answer
46 views

How to create a database with “polymorphism”

I'm sorry I'm new when it comes to databases, I'm using Access right now to develop a database to store calibration data for a bunch of different types of transducers. Each type of item is ...
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1answer
37 views

Should I create many ID for a same Person/entity in my DB?

In my model, I must store the name of the teacher of some kids and the classroom in which the teachers work, let’s say. All of the hundreds of teachers in the schools have 1 and only 1 classroom, ...
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1answer
84 views

Multiple Cascade Paths (Not really) - Sql Server

In my database I have a table with 2 columns referencing the same column in a separate table. I know this creates a race condition, but I have a check in place to make sure they don't point to the ...
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80 views

Problems in Choosing Foreign Keys :S

I am designing my very first relational database. I am now in the conceptual design, building tables and views, selecting the primary and foreign keys and normalizing everything. But now, I am stock ...
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23 views

SQLITE Foreign key has to be re-added? [closed]

Currently I have a mysql database on my computer which I convert to sqlite database. On the sqlite database, I have transaction_detail table with a foreign key to transaction_master table. The ...
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125 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
144 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 ...
3
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2answers
385 views

Advice on a basic design, first time database design

I am taking a course to become a Java developer. The course involves using databases but we never really design any unfortunately. Most of the time we get pre-made databases and we have to implement ...
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1answer
310 views

Have foreign key constraint and index key for the same column(s)

I am creating a composite index key for 2 columns and then adding foreign keys to its appropriate table. Do I need to create a multiple index key reference and then create separate foreign keys? My ...
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59 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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23 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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26 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
48 views

Adding NotNull FK field in existing DB

Context: We’re building a web application to manage business-data. Each “client” of the application has a separate DB (this wont change), and each DB is based off a model (so they are all identical in ...
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1answer
95 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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0answers
45 views

Update all foreign keys to a different primary key

In a MySQL database, I have a table full of business information. Lots of businesses have been inserted twice due to human error, so the same information exists with two different primary keys. ...
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1answer
296 views

Foreign keys become untrusted after bulk insert

In a SQL 2014 edition server (12.0.2430.0 - no SP1 yet) with a database in 2012 compatibility mode (working on getting it switched to 2014...) I have a handful of foreign key objects which are ...
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2answers
784 views

Is it acceptable to have circular foreign key references\How to avoid them?

Is it acceptable to have a circular reference between two tables on the foreign key field? If not, how can these situations be avoided? If so, how can data be inserted? Below is an example of ...
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1k views

Naming foreign key columns

Now I hear that the best practice for naming foreign key columns is the name of the table and field (and maybe the function if there are multiple foreign keys to the same table), for example, a ...
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122 views

How often will a FOR EACH STATEMENT trigger execute if the operation is caused by an FK constraint with UPDATE CASCADE?

I understand that a trigger on table t defined with FOR EACH STATEMENT will run once when I execute an UPDATE t .... Now, when t is defined with FOREIGN KEY ... REFERENCES a ... ON UPDATE CASCADE, ...
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1answer
536 views

Deferrable Foreign Key Constraints

What are the consequences of making a foreign key constraint DEFERRABLE INITIALLY IMMEDIATE instead of NONDEFERRABLE? This answer on StackOverflow mentions the performance impact that comes with no ...
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1answer
49 views

Can you enforce uniqueness in MySQL based on column in foreign table?

I am refactoring one of my database tables and I've come up with an issue. Specifically, I have a table with four columns. We'll call the first three my.a, my.b and my.c. I have a uniqueness ...
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1answer
34 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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221 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

Compound key that only allows nulls if they are null in the referenced table

I want to create a compound foreign key constraint that only allows a null value in one of the columns if there is a matching row with a null value in the referenced table. Additionally, the ...
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77 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
114 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
84 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 ...
2
votes
1answer
57 views

Is there any point in specifying the precision and scale of a number for a foreign key?

I am running Oracle 11gR2 11.2.0.3. I have two tables: table1 contains a column named SUBJECT_ID, whose datatype is NUMBER(7,0) (numbers range from 13 to 48480) table2 contains a a column named ...
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1k 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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23 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
338 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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1answer
103 views

How to get a surrogate key value in order to put a foreign key in and create relationship?

I am trying to create two relationships between three tables, using foreign keys with values of primary keys, which are surrogate keys. But I don't understand how to enter the right value in the ...
3
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1answer
250 views

Enforcing constraints “two tables away”

I ran into some trouble modeling an electrical schematic in SQL. The structure I'd like to capture is part ←────────── pin ↑ ↑ part_inst ←───── pin_inst where "inst" is short ...
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47 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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70 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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1answer
56 views

Query perfomance with multiple JOINs on MyISAM-based DB

I'm working with Enron Email Dataset in MySQL database. After I executed data import from the dump file into MyISAM-based DB, I got the set of tables without any connections between them via foreign ...
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42 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 ...
0
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2answers
123 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
439 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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2answers
144 views

Oracle: finding rows without children in a table with a foreign key?

Suppose I have two tables with a foreign key relationship. How can I find the rows in the parent table for which there is no corresponding child record? For example: create table a(x number primary ...
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1answer
77 views

Oracle: Traversing a graph of my foreign keys?

Given a table, what is a query that will show foreign key constrains, both immediate and nested? I.e. if T2 has an FK on T1, and T3 has an FK on T2, I would like to show T1 -> T2 -> T3.
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212 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 ...
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50 views

Is there a workaround for the lack of foreign keys constraint to a partitioned table in PostgreSQL?

I have a big table A (~30 million lines) at the core of my model. Another table B has a foreign key referencing A. I would like to partition A using the well-known inheritance hack. Is there a ...