INFRA Database Design - DBA View

What does the DBA want to see? The DBA wants to see the databases, of course.

Database

So the Database Entity is going to be a central player in the part of the INFRA database that supports DBAs. What is a Database? It is a means of storing, retrieving, and organizing the data that is behind an application system. In short, it is your major tool to save the data and change data into information, A Database is managed by a Database Instance which is a special case of a Service – we’ll talk about Services when we look at some of the other views. In an earlier blog post I talked about databases and database instances in more detail. For our purposes here, a Database Instance is the executing software that manages the files that contain your Database. An instance is an instance of a particular vendor’s or source of database software such as Oracle, SQL Server, Cassandra, or whatever, and one of its attributes will be which version of this software is running.

Application Database

Where the Database entity represents a general term, the more specific meaning of the word, database, is the database objects that are created to store and retrieve the data for a particular application system. To distinguish the two, I have chosen to call this the Application Database. For instance, an HR application might have database objects for information about Employees and Departments, while an Order/Entry application might have objects for Customers, Orders and the Order Line Items in those orders. These objects might be stored in any kind of a database as decided by the developers of that application system. Notice that an Application Database can store data for more than one Application System and an Application System can use data in more than one Application Database. This is in recognition that some data is shared between application systems, though usually only one system may maintain the data while others only read it.

Database Version

My Database Version entity is really an Application Database Version – I just left off the word, “application”, for brevity. The version supports the fact that Application Databases change over time, just as the applications that use them do. So a Database is the target of a deployment of one and only one Application Database Version, but can contain versions of more than one Application Databases. As a general rule, it will contain only one version of any single Application Database. Not shown on the diagram below is the relationship between Application System Versions and Database Versions. Usually a version of an application system is developed side by side with a version of its database, so the Deployment Manager needs to know which two versions correspond. You’ll see this when we get to that view.

Entity Relationship Diagram for DBA’s View