Tagged Questions
1
vote
1answer
16 views
MySQL Insert Row With Foreign Key Equal to ID - Circular Reference
In MySQL database I have an events table which has a circular reference to itself with the following columns.
id (PK) | user_id (FK) | event_id (FK) | title
Each new row inserted has a circular ...
1
vote
1answer
98 views
Multiple primary keys
I am new to database design and have been looking at some example data models here.
One thing I don't understand is if you have a table like client_addresses from the link above:
...
0
votes
1answer
321 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 ...
3
votes
1answer
445 views
Why does altering a table and adding a foreign key create an extra constaint?
Edit: It was a default constraint as a result of setting a default value when adding the column. The name gave it away when starting with 'DF__'. Anyway, solved it by adding the column and manually ...
1
vote
1answer
326 views
Using a foreign key on multiple fields in one table
Simple question probably.
For two tables. A one to many relation is created from A -> B, TeamID -> Fk_Team, however there are multiple fields that need to reference this one relationship how does ...
1
vote
2answers
2k views
How to use RESTRICT for Foreign Key in mysql?
In the database structure of
CREATE TABLE Country (
name varchar(40) NOT NULL,
PRIMARY KEY (name)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE City (
name varchar(40) NOT NULL,
...
1
vote
1answer
215 views
Usefulness of Foreign Key WITHOUT reference option
Sorry, if this is naive question, but I searched a lot and did not get a vivid answers. Consider a simple InnoDB FOREIGN KEY without ON DELETE or ON UPDATE
I think this will avoid INSERT of a value ...
3
votes
2answers
511 views
Using Foreign Key and References for ON DELETE CASCADE in mysql
I was thinking that these two ways for creating foreign keys are the same
CREATE TABLE child1 (
id int(11) not null auto_increment,
parent_id int(11) REFERENCES parent_table(parent_id) ON DELETE ...
1
vote
2answers
431 views
Usage of RESTRICT or No ACTION in FOREIGN KEY Constraints
Sorry if this question is naive, but I was unable to understand possible usage of RESTRICT or No ACTION. Consider a simple database of
CREATE TABLE column1
(
first_id int(11) NOT NULL AUTO_INCREMENT,
...
-1
votes
2answers
465 views
Multiple child tables
I would like to know what is the best solution for making a parent table with multiple children?
I have to make multiple children table. One for each profile.
Is there a better idea than having 3 ...
5
votes
2answers
692 views
How to retrieve foreign key constraints data
I'm looking for a query allowing to retrieve foreign key infos (each line: referrencing table & field, referrenced table & field) of an entire schema.
I've found this, but does not gives all ...
0
votes
2answers
637 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.
...
