What were some of the different implementations of SQL, this Structured Query Language? Well, originally in the mainframe world, the IBM platform led to DB2 and system R. This was a database that could be shared across several different applications. As PC computers took off in the early 1980s, a file-based relational model came up in various, what was called xBase or dBASE or FoxPro Clipper. These were programs that were very popular in the 1980s and allowed rapid deployment of database techniques and technology to even much simpler end users for a tremendous cost savings over centralized mainframes. Towards the mid and end of the 1980s, a client-server technology evolved, which is still for a large part of the predominant technology today. These lead to the initial SQL champion of Oracle, Larry Ellison developed Oracle in the late 70s. Then there was a company called Sybase that merged with Microsoft, merged its code with it, or there were a variety of different events that I won't cover right now. Then Microsoft launched SQL Server in the late 80s and has become a solid competitor with Oracle. More recently, you say in the 90s and early 2000s, a set of open source MySQL, and is implementation of SQL that many websites use today. The latest or the subsequent technology platform is cloud-based. Many people say we live in a post relational world and there are many databases like MongoDB and Amazon Services and other Microsoft Azure, they're many cloud-based services and there are many other options now for data storage than a purely relational model. But for clinical informatics and clinical data, the relational model is still quite predominant. There are research clouds and research based implementations of broader mix of cloud and relational data, but most hospital operations are still based on relational models. Let's take a more detailed look on what are some of the components, for example, of SQL Server, of a typical relational server setup. These technology components will have a big part to play in any informatics planning project or implementation. A server anatomy, you would see these basic components. Server anatomy really means the layers of software that are installed on a SQL Server. First and foremost, there's the Operating System. Speaking for example about Microsoft, we would say that an example would be a Windows Server Operating System, but there are many other operating systems that support databases, Linux and Unix and other platforms. The SQL Server itself is a type of software that is installed on top of the operating system, and it essentially receives requests for data, structures data, and returns data back to whoever requests it. Within that breakdown of that SQL Server software, it organizes data into what it calls a database. So each database is a collection of objects, primarily something called tables and other code and relationships, as we said in the informatics discussion that database stores data and its relationships. These relationships are enforced through referential integrity type of code and also implicit rules that are built into the database. Next, there's a layer of security. Data, as it grows and gets more complex, has more complex security rules. The security rules are not just enforced at the operating system, but they're also enforced within the database. There are logins and different database users and roles and there's very complex security that can be implemented in a database. The client is the person or process that makes a request to the server. Again, it's client-server in this platform. A client might be a web page or might be like an Excel or even Google Sheets or something like that, that goes and connects to a database and makes a request to that database. Most people have encountered this frequently. If you go to an airline website, when you type in, "I'd like to see flights to Florida in this particular time frame, " this is just a theoretical discussion, I'm sure no one's ever done that. That is actually making a request to a centralized database and returning back data from that database and then formatting it in a web page. That would be an example of a client. Clients can use a variety of common protocols that are systemwide, OLEDB or JDBC. There are other types of connection protocols and they're used again by these applications, either SQL Server has a client, there's a SQL client that you can write SQL code in called SQL Server Management Studio. Or there are a number of other coding platforms that you can write your own SQL requests. Websites and services, as we've just discussed, and then, for example, Excel or Google Sheets, something like that. These can all make request to the database.