A data connection definition defines the connection properties for a data source. Connection properties include connection type, security policy, user name, and password. The first time you create a data connection definition for a project, the IO Design perspective creates the IO Designs folder hierarchy in the project folder. For example, for a project named MyProject, the IO Design perspective creates the folder hierarchy /IO Designs/MyProject/Data Sources. The folder hierarchy contains the MyProject subfolder because all information object files are published to the IO Designs subfolder located in the Resources folder in the volume using the same relative path used in the workspace. The project name is required to distinguish the information object files belonging to one project from those belonging to other projects.

The IO Design perspective then creates a subfolder in the Data Sources folder of the project to contain the data connection definition file. For example, if you create a data connection definition for the MyDatabase database, the IO Design perspective creates the MyDatabase subfolder and the _MyDatabase.dcd data connection definition file, as shown in Figure 2‑5.

A data connection definition file has a .dcd file‑name extension. Data connection definition file names are not case-sensitive.