D

Database administrators (DBAs) People that handle the databases that systems use.

Database schema The structure of a given database, which defines the tables in the database and their data elements (fields), as well as the relationships between the tables.

Data flow diagram (DFD) A block diagram that describes how data is entered into a system resulting in useful information.

Datacenter The primary room in an organization's building where the servers are housed. Often the routers, switches, and telephony gear are kept in the datacenter as well, in which case it may be called an MDF ( see Main Data Facility).

Decision model A formal method of project selection that helps managers make the best use of limited budgets and human resources. Includes benefit measurement methods and constrained optimization models.

Decomposition The process of breaking project deliverables down into smaller, manageable components so that project tasks and activities can be planned and estimated.

Definitive estimate An estimating technique that assigns a cost estimate to each work package in the project WBS. The most accurate of the cost estimating techniques.

Demarcation The termination juncture where a telecommunications company provides the interface for wide area networking (WAN) services, such as T1 or ISDN.

Dependencies The relationship between two project activities.

Dependency relationships Identifying the type of dependency between two activities and the specific relationship between the activities.

Discounted cash flow (DCF) Compares the value of the future cash flows of the project to today's dollars.

Discretionary dependency Something that the project manager and project team choose to impose on the project schedule, such as the use of an established corporate practice.

Document control process Defines how revisions are made, the version numbering system, and the placement of the version number and revision date.

Duration compression The use of techniques such as fast tracking or crashing to shorten the planned duration of a project or to resolve schedule slippage.