foreign-key-relationship

I am trying to delete a few records but am getting the following error: Cannot delete or update a parent row: a foreign key constraint fails The thing is, the foreign key constraint is failing for only 1 or 2 of my 100 records I wish to delete. I wish to write a query which deletes these 98-99 records, skipping the 1 or 2 which failed , which I can later manually inspect and delete/modify. Not stopping because of some single problematic record, but continuing with the others, ignoring that. Is there a neat way to do this ? You have to LEFT JOIN the referencing table and add a condition saying

Let's suppose that we have this situation: Tables in database: Country (id, country_name), Person (id, login), CountryManager (id_country, id_person), CountryStakeholder (id_country, id_person) If we had to create the model from the database, using Entity Framework Database-First, in VS we'd have a class like this: class Country { int id; string country_name; virtual ICollection<Person> Person1; // Navigation Properties virtual ICollection<Person> Person2; // ---------||---------- } I've simplified the code a lot, but hopefully you got the point. Seems that when Entity Framework deals with

Similar but NOT IDENTICAL to SQL Server 2000 - Query a Table’s Foreign Key relationships I need a T-SQL statement that will work SQL 2000 that given a table name, will return the foreign key relationships for that table e.g. Table MyFristTable has a foreign key to MySecondTable, where MyFirstTable.ColA must be in MySecondTable.ColB. I'd be delighted, if the sql statement (or stored proc) is ran for MyFirstTable and returned a result set on the lines of Column | FK_Table | FK_COLUMN ---------------------------------- ColA | MySecondTable | ColB NB : I have samples for SQL 2005 that won't work

I have two classes: Artist and Instrument . Each Artist can play one or more Instrument s. And each Instrument can be assigned to one or more Artist s. So, I've set up the following Classes: Artist.php public function instruments() { return $this->belongsToMany('App\Models\Instrument'); } Instrument.php public function artists() { return $this->belongsToMany('\App\Models\Artist'); } Then I have three database tables: artists: id, firstname, lastname, (timestamps) instruments: id, name artist_instrument: id, artist_id, instrument_id I'm able to successfully retrieve a one artist and their

This is a SQL design question. First, the setup. I have three tables: A, which is automatically populated based on a query against a linked server. The data in this table cannot be changed; B, which has just a dozen or so rows, containing the names for collections of As; AtoB, which is the mapping table by which As are organized into named collections, with foreign keys on both columns; For example, A contains: Giraffe Owl Tiger And B contains: Seattle Zoo San Jose Zoo And AtoB contains: 1,1 (Giraffe in Seattle) 2,1 (Owl in Seattle) 3,1 (Tiger in Seattle) 2,2 (Owl in San Jose) Now, the problem

I have table 1 with a primary key user_id and table 2 where user_id is a foreign key. Only 1 record per user_id can exist in table 2, and no record can exist without it. QUESTION: Can user_id in table 2 be both foreign and primary key at the same time, and if yes, is it a good idea, what are pros/cons? Yes, you can do this (and you should, from a database design point of view). However, consider what it means if user_id is the primary key on table 2. You are in effect saying that each row in table 2 corresponds to a user, but you already have a table where each row corresponds to a user: table

I have the following models Category: <?php class Category extends Eloquent { protected $table = "category"; protected $fillable = array('title','parent','metatit','metadsc','metake','metaurl','image'); public function categoryitems(){ return $this->hasMany('CategoryItem','catid'); } public function parent(){ return $this->hasMany('category','parent'); } public function child(){ return $this->belongsTo('Category','parent'); } } Need to set a 1 to many relationship in the category table Ex category "cities" is a child of category "countries" the error happen when i try to use the following code

I'm unable to grasp that from the docs. It's totally unclear to me, more specifically: Is it a global setting? So if I specify this attribute it on one of the model managers, will it be used globally by all the model classes? If it's not a global setting then which relationships exactly will be affected? Is it possible to have one model manager for one relationship and another one for another relationship with the same model? Most of all I would appreciate any good minimal example usages as the documentation lacks those afaik. Thanks. Is it a global setting? So if I specify this attribute it