Let's say I have an existing database with the following 3 tables: Table1: (PK)T1ID1 (PK)T1ID2 Table2: (PK)T2ID1 Table3: (FK)T1ID1 (FK)T1ID2 (FK)T2ID1 (Where the 3 keys come from the tables above) My question is: How do I map Table3 with Fluent NHibernate? What is confusing to me is what to do about the fact that its composite keys c...
For various reasons that aren't too germane to the question, I've got a table with a composite key made out of two integers and I want to create a single unique key out of those two numbers. My initial thought was to just concatenate them, but I ran into a problem quickly when I realized that a composite key of (51,1) would result in the...
Hey, i'm trying to delete an entity of the following structure from an Oracle 10g tables: class Record { string id; string name; DateTime dateTime; } with the following mapping: <class name="Records" table="RECS"> <composite-id> <key-property name="P_ID" /> <key-property name="NAME" /> </id> <property n...
Hi all, I saw that exist more then one way to map a Composite Key with JPA. But in my case is kind of different: I have a table with only 2 column: mysql> desc mytable; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------...
Hi, The re-design for a large database at our company makes extensive use of composite primary keys on the database. Forgetting performance impacts, will this cause any difficulties when working with this db in Entity Framework 4.0? The database structure is unlikely to change and I'm not looking for "philosophical" debate but what are...
Hi So I have this table with a composite key, basically 'userID'-'data' must be unique (see my other question http://stackoverflow.com/questions/2026379/sql-table-semi-unique-row) However, I was wondering if it was possible to make this only come into effect when userID is not zero? By that I mean, 'userID'-'data' must be unique for no...
OK, so here is the problem. Its not even as crazy as the guy who wants to map m:n with different column counts in his PKs. No matter what I do or where I look there seems to be no method chain that will result in a successful mapping of this. I have tried doubling up on the Parent and Child columns, eg ParentColumn("").ParentColumn(""...
The title says it all. I have a composite key in a database table / NHibernate entity. Can I somehow use the .Get method to grab a specific entity or do I have to use HQL / Criteria due to the composite key? ...
Is it necessary that composite-id should be mapped to class ?? can it be like this ? <composite-id> <key-property=..../> <key-property=..../> </composite-id> or should be <composite-id class=....> <key-property=..../> <key-property=..../> </composite-id> should that necessary that if we have composite key then that class ...
Can a compound key be set as a primary key to another table? For instance i have the tables: Books -with Primary Key:Product_ID Client -with Primary key: Client_ID Clients_Books -with Compound Primary Key:Product_Id and Client_ID I want to set this compound Primary key from Clients_Books as a Primary Key to another table named: O...
I have Events, Documents, and Surveys which all need to be able to link to one another, I was planning on having a linking table with four columns as follows: link_elements{ element1_type CHAR(1) element1_id INTEGER element2_type CHAR(1) element2_id INTEGER } The problem is I can't figure out how to make the model in RoR so th...
I have the following schema (* means primary key): languages id* english_name native_name native_to_target_language native_language_id* target_language_id* target_language_name overview_text (target_language_name is the name of the target language as written in the native language). I want to get the value of target_la...
I've followed the instructions here, installing the composite_primary_keys gem via sudo gem install composite_primary_keys That worked fine. Now when I add the following to my model set_primary_keys :user_id, :group_id and I get undefined method `set_primary_keys' for #<Class:0x1043bfe20> Also, using multiple primary keys in a m...
Ok, I have a table that will look something like this: Post ˪ Id ˪ Version ˪ Title ˪ Content The idea is that the Id and Version together will be the primary key since you can have a single post multiple times but of different versions. My question is this: I would like to have the Id to auto increment. Is this possible in a setu...
I have 2 tables with a composite foreign key between the 2. When I try to insert a row into the child table, I get a restraint failure, even though the values exist in the parent table. Here's a overview of the parent table: CREATE TABLE `residual_reports` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `processor` enum('1','2','3...
By default the behaviour of FNH is to map enums to its string in the db. But while mapping an enum as part of a composite key, the property gets mapped as int. e.g. in this case public class Address : Entity { public Address() { } public virtual AddressType Type { get; set; } public virtual User User { get; set; } ...
I am writing a new app with Rails so I have an id column on every table. What is the best practice for enforcing domain constraints using foreign keys? I'll outline my thoughts and frustration. Here's what I would imagine as "The Rails Way". It's what I started with. Companies: id: integer, serial company_code: char, unique, no...
Hi, I am bit confused on making a good relational database. I am using phpmyAdmin to create a database. I have the following four tables. Don't worry about that fact place and price are optional they just are. Person (Mandatory) Item (Mandatory) Place (Optional) Price (Optional) Item is the main table. It will always have person...
Hi, I'm not sure how to use composite key. My Categories table has CategoryId (PK,FK), LanguageId (PK,FK), CategoryName CategoryId | LanguageId | CategoryName 1 | 1 | Car 1 | 2 | Auto 1 | 3 | Automobile etc. I'm following this design The default action looks like // // GET: /Cat...
Hi, I'm using Hibernate with annotations (in spring), and I have an object which has an ordered, many-to-one relationship which a child object which has a composite primary key, one component of which is a foreign key back to the id of the parent object. The structure looks something like this: +=============+ +=======...