foreign-keys

Foreign key constraints are not copied when using create table table_name ( like source_table INCLUDING ALL)' in Postgres. How can I create a copy of an existing table including all foreign keys. There is no option to automatically create foreign keys in CREATE TABLE ... LIKE ... . For the documentation: LIKE source_table [ like_option ... ] Not-null constraints are always copied to the new table. CHECK constraints will be copied only if INCLUDING CONSTRAINTS is specified [...] Indexes, PRIMARY KEY, and UNIQUE constraints on the original table will be created on the new table only if the

I understand that by default the id field is created and also: PRIMARY KEY ( id ) . How about the foreign key ? I have Shops and Products tables and the following associations: Shop: has_many :products Product: belongs_to :shop In Product I have also: t.integer "shop_id" which is meant to be the foreign key, and also: add_index("products", "shop_id") However, if I export the database I see only: KEY `index_products_on_shop_id` (`shop_id`) What should I do in order to add FOREIGN KEY (`shop_id`) REFERENCES Shop(`id`) ? You can use the foreigner gem for adding foreign keys to your application.

Hi I have a problem to create a table using migration schema builder. The problem occure with table with self referencing foreign key. Here is the code which produce error: Schema::create('cb_category', function($table) { $table->integer('id')->primary()->unique()->unsigned(); $table->integer('domain_id')->unsigned(); $table->foreign('domain_id')->references('id')->on('cb_domain'); $table->integer('parent_id')->nullable(); $table->foreign('parent_id')->references('id')->on('cb_category')->onUpdate('cascade')->onDelete('cascade'); $table->string('name'); $table->integer('level'); }); Here is

I am not clever from ORMlite documentation. Is is possible to declare in class, that this parameter is foreign key? e.g. I have table Customer: @DatabaseTable(tableName = "customer") public class Customer { @DatabaseField(id = true) private String customerName; @DatabaseField private String customerSurname; @DatabaseField(foreign = true) private String accountNameHolder; @DatabaseField private int age; public Customer() { } } AccountNameHolder should aim towards DatabaseField name from table Accounts. How to do that? I have found only parameter foreign = true, but there is nothing about, which

Possible Duplicate: What’s wrong with foreign keys? I use MS Sql Server with a large database about 4 GB data. I search around the web why I should use foreign keys. by now I only indexed the keys used to join tables. Performance is all fine, dataintegrety is no problem. Should I use foreign keys? Will I get even more performance with foreign keys? Foreign key's don't actually improve performance, in fact they incur a small performance penalty on all write operations, to ensure that the constraint is followed. The reason why you want to use these is to prevent destructive write operations. If

What is the advantage of defining a foreign key when working with an MVC framework that handles the relation? I'm using a relational database with a framework that allows model definitions with relations. Because the foreign keys are defined through the models, it seems like foreign keys are redundant. When it comes to managing the database of an application in development, editing/deleting tables that are using foreign keys is a hassle. Is there any advantage to using foreign keys that I'm forgoing by dropping the use of them altogether? Foreign keys with constraints(in some DB engines) give

I know what they are my question is, how do you link them or are they automatically linked when you have identical names in different tables. Here is an example: Say I have an [orders] table and a [customer] table. Each row in the [orders] table has a customer_id number which is associated with the customer_id in the [customer] table. So how do I get the customer information by referencing the order? What would be the sql query? ... how do you link them or are they automatically linked when you have identical names in different tables. This is not automatic, you have to add a foreign key