Being one of developers of Open Link Virtuoso team, I'll describe technical details in terms of Virtuoso SPARQL extensions.One of good starting points is Carl Blakeley's Mapping Relational Data to RDF with Virtuoso's RDF Views, more details can be found in Virtuoso User's Guide Consider a very traditional Northwind database: "customers" make "orders", orders consists of "order lines" that mention different "products" of different "categories", "products" are shipped by "shippers" from "suppliers".No two customized applications are alike, and hence, no two database are alike.Guidelines (usually in terms of what not to do instead of what to do) are provided in making these design decision, but the choices ultimately rest on the you - the designer.With both of these controls you can specify the clause as properties of the Data Source controls.The code to connect to the database, issue the command, and retrieve the results is handled internally by the Data Source control.
In fact, the Access Data Source control is really superfluous since Microsoft Access databases can be accessed through the Sql Data Source control just as easily.
Today, there are many commercial (RDBMS), such as Oracle, IBM DB2 and Microsoft SQL Server. However, the relationships that can be created among the tables enable a relational database to efficiently store huge amount of data, and effectively retrieve selected data.
There are also many free and open-source RDBMS, such as My SQL, m SQL (mini-SQL) and the embedded Java DB (Apache Derby). A language called SQL (Structured Query Language) was developed to work with relational databases.
Because of this indeterminacy, referencing other tables only within sub-selects is safer, though often harder to read and slower than using a join.  Set the value of column C1 in table T to 1, only in those rows where the value of column C2 is "a".
In this tutorial, will we show you how to create a My SQL database for a Content Management System (CMS) that we will be creating in an upcoming tutorial.