foreign-keys

MySQL attempting to delete all rows which are not constrained by foreign key.

Okay, this is (probably) a very simple question, but I am afraid I know almost no MySQL, so please put up with me. I'm just trying to delete every row from one table which is not constrained by a Foreign Key in another table - a specific table, there are only two tables involved here. The create statements look a bit like: CREATE TABLE ...

Adding new fields vs creating separate table

I am working on a project where there are several types of users (students and teachers). Currently to store the user's information, two tables are used. The users table stores the information that all users have in common. The teachers table stores information that only teachers have with a foreign key relating it to the users table. u...

Unable to add foreign keys manually in Entity Framework 4

So I have a sql server 2008 database with 9 tables in them, they don't have any set relationships but is still used as if they have it, this however makes it so that I cant import the relationships when importing the models from the database. Now, when trying to add an association between two tables work but when I want to point tb1.Id ...

With SubSonic is there a way to express relationships without foreign keys?

Our database does not have foreign keys, but we wish to be able to use SubSonic. Are there any ways except for foreign keys to express relationships between tables? Also see this related question ...

SubSonic 3.0 Migrations Vs. SimpleRepository Auto-Migrations: Foreign keys support?

Hi All, I'm considering using SubSonic to create and access an SQLite database. Not sure yet what flavor fits better for me though I tend to prefer the SimpleRepository approach. Indeed I don't expect my DB to do much more than storing my objects and basic querying. I've been through to docs but there are still a few points unclear to ...

This is wrong: a column can references primary keys in different tables depends on value of another column?

One of my colleague designed a table schema, and in one of the tables a column can references primary keys in different tables depends on value of another column. I know it is differently wrong, but can not find theory to support me. His schema like this: table video: (id, name, ...) table audio:(id, name, ...) table review_item( item_t...

What is this "_ifbk" constraint doing in my table?

I'm working on a Rails web application with a MySQL database. I'm using migrations to modify the schema. I've just run into a problem wherein I'm getting an invalid record error on inserting a new record. The relevant tables: users id | name | email | ... academic_records id | scholar_id | gpa | ... academic_records.scholar_id is a ...

SQL Server composite key problem

I have 2 tables: create table numbers2 ( id1 int IDENTITY(1,1) not null, id2 int not null, primary key(id1, id2) ) and table 2 create table ttt ( id int identity(1,1) not null, first_name varchar(50) null, last_name varchar(50) null, sex varchar(1) check (sex in ('m', 'f')) null, number_id int not null, id_id1 int not null, id_id2 i...

Add Sort Order for FOREIGN KEY CONSTRAINT on SQL Server

How do I add the Foreign Key Sort order in the following statement: ALTER TABLE [dbo].[ActionLog] WITH CHECK ADD CONSTRAINT [FK_ActionLog_Order] FOREIGN KEY([OrderID]) I want the OrderID to be descending. ...

Filter foreignkey field from the selection of another foreignkey in django-admin?

hi, i have the next models class Region(models.Model): nombre = models.CharField(max_length=25) class Departamento(models.Model): nombre = models.CharField(max_length=25) region = models.ForeignKey(Region) class Municipio(models.Model): nombre = models.CharField(max_length=35) departamento = models.ForeignKey(Depar...

Is it possible to assign default display value when ForeignKey is None in Django?

I have ForeignKey in my Django model which can be null. group = models.ForeignKey(Group, null = True, blank = True) In case of null value assigned I want to render some specific text in templates (eg. "No grooup assigned"). I use default filter and it's OK except that I repeat this code in various templates. I am looking for solution...

Seeking Embedded Database alternative to SQLite. Must have foreign key contraint and transaction support?

Do you know of any SQLite alternatives (Portable/flatfile based/serverless) that have foreign key constraint and/or offer transaction support? ...

myssql foreign key whic is a composite key - what is the syntax?

Is it possible to have a composite key in mysql(5.1) and if so, what is the syntax? table a: column aa,bb references table b columns b_aa,b_bb ...

Is there a way to bulk insert into two tables with FK from one to the other?

I'll give a pseudocode example of my current method and if anyone knows of a method that doesn't work one row at a time, I'd be quite appreciative. I'm using MS SQLServer 2008 define cursor for the data to be inserted (about 3 million records) loop ( insert record into table 1 use scope_identity() to get key insert record into tab...

SQL Referencial Integrity Between a Column and (One of Many Possible) Tables

This is more of a curiosity at the moment, but let's picture an environment where I bill on a staunch nickle&dime basis. I have many operations that my system does and they're all billable. All these operations are recorded across various tables (these tables need to be separate because they record very different kinds of information)....

i got ibfk_5 when trying input forreign key to table

I have structure table like this. the problem is : When i want to input data to "index" table. I got this error. com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (test.index, CONSTRAINT index_ibfk_5 FOREIGN KEY (b_FK) REFERENCES...

is there a way to do a reverse lookup in nhibernate?

i have two tables: Components ComponentDependencies ComponentDependencies has two columns: ComponentId and ComponentDependencyID. (both foreign keys into Id field of Component table. i am using fluent nhiberate and i have my component object having: public virtual IList<ComponentDependency> Dependencies { get; set; } and in my C...

MySQL foreign key question

Does defining a foreign key also defines a index? I have mysql v5.1.46 & I am looking at the MySQL Administrator tool and its shows the foreign key as an index, so I wanted to confirm? ...

Why aren't my sqlite3 foreign keys working?

I run the following code from a python interpreter, and expect the insert statement to fail and throw some kind of exception. But it's not happening: Python 2.6.5 (r265:79096, Mar 19 2010, 21:48:26) [MSC v.1500 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import sqlite3 >>> conn = s...

Checking integrity of deferred foreign keys in Oracle

Deferred foreign keys are useful because Oracle checks the integrity of the foreign key constraint only on commit and not after each statement. Although this deferred integrity checking is very useful, sometimes I'd like to check the integrity without executing commit. Is it possible somehow? (Without changing the constraints to non-def...