relational-database

I have information about music albums that I want to organise in RDBMS tables with relations between them. I have the following info for each album: artist, album name, year, label, genre, style, rating. So far I think to make 4 tables - artists, albums (name, year, label, rating), genre1 and genre2 (each genre with its styles). On the diagram it looks as follows: But don't know yet how can I establish a connection between albums and the other three tables? I.e., when I will run a query select name from artists I would like to receive an album with corresponding artist and genre-style. How

My query includes a having and count or all in. How are these represented in RA/DRC/TRC? Would I have to simplify my SQL query even more? Here is a simplified example: empl(employee (primary key), city) managers(employee (primary key), manager (foreign key of employee)) If I were to find all the employees who are managers (from any city) of ALL the employees in city X.. I would need to use having/count. Not sure how this would be done in RA/DRC/TRC. I know the need for such a query might not make sense but assume it is sensible for the purpose of this question. Thanks Your query was stated a

Here's an exmaple: Originally I have 3 tables. Table B references Table A. So now Table B has two primary keys. One used as the original primary key and the other one to enforce its relationship with Tabe A. Then I want Table B to have a many-to-many relationship with Table X. As I'm adding the relationship, MySQL Workbench added Table Y with both of Table B primary keys and one primary key in Table X. So Table Y now has three primary keys. It seems like the second primary key from Table B in the junction table is unnecessary since I can identify Table B with the original primary key. So do I

I want to know if there is a way to have multiple values in a single field in a MySQL database where each value is a foreign key referencing one other table. I am designing a database with a product table and a product certification table. I am using InnoDB and foreign key constraints. The "product" table contains the details about specific instances of the product. One of the details contained in the product table is the column “product_certification_id”, which is a foreign key referencing an index in the two column “product_certification” table. The product certification table contains the

In the database world, we have normalisation. You can start with a design, crank the steps and end up with a normal form of the database. This is done on the basis of the semantics of the data and can be thought of as a series of design refactorings. In object orientated design, we have the SOLID principals and various other adhoc guidelines towards good design. Do you think it is possible to define the equivalent of normal forms for OO, such that a series of refactoring steps could move a procedural piece of code (or poorly factored OO design) into a correct (in some well-defined sense)

I'm pondering the design of an application where the main feature revolves around the ability to find the set of all sets which are subsets of a given set. For example, given the input set A={1,2,3...50} and the set of sets B={ B1={3,5,9,12}, B2={1,6,100,123,45} ... B500={8,67,450} }, return all Bs which are a subset of A. I guess it's similar to a search engine, except that I don't really have the luxury of set A being small and the Bs being large; in my case Bs are usually smaller than A. I found a similar question here , but was wondering if there was anything more efficient / standard.