Database Reference
In-Depth Information
A secondary key is one or more data elements (if more than one data
element, it is called a composite secondary key) that are accessed fre-
quently and need to be retrieved quickly. A secondary key does not
have to be unique, or stable, or always contain a value.
A Slowly Changing Dimension (SCD) is a term for any reference entity
where we need to consider how to handle data changes. There are four
basic ways to manage history. An SCD of Type 0 means we are only
interested in the original state, an SCD of Type 1 means only the most
current state, an SCD of Type 2 means the most current along with all
history, and an SCD of Type 3 means the most current and some history
will be stored.
slowly changing
dimension
(SCD)
A spreadsheet is a representation of a paper worksheet containing a grid
defined by rows and columns, where each cell in the grid can contain
text or numbers. The columns often contain different types of informa-
tion.
spreadsheet
A stakeholder is a person who has an interest in the successful comple-
tion of a project.
stakeholder
A star schema is the most common physical dimensional data model
structure. A star schema results when each set of structures that make up
a dimension is flattened into a single structure. The fact table is in the
center of the model and each of the dimensions relate to the fact table at
the lowest level of detail.
star schema
subject matter
expert (SME)
A person with significant experience and knowledge of a given topic or
function.
A surrogate key is a primary key that substitutes for a natural key, which
is what the business sees as the unique identifier for an entity. It has no
embedded intelligence and is used by IT (and not the business) for in-
tegration or performance reasons.
surrogate key
