Contents
What is a dimension and fact?
Facts and dimensions are data warehousing terms. A fact is a quantitative piece of information – such as a sale or a download. Facts are stored in fact tables, and have a foreign key relationship with a number of dimension tables. Dimensions are companions to facts, and describe the objects in a fact table.
What is the dimension of the null space?
The dimension of the Null Space of a matrix is called the ”nullity” of the matrix. f(rx + sy) = rf(x) + sf(y), for all x,y ∈ V and r,s ∈ R. fA :Rm −→Rn which is given by: fA(x) = Ax, for x ∈ Rm .
Are dimension and rank the same?
Dimension is the number of vectors in any basis for the space to be spanned. (2.) Rank of a matrix is the dimension of the column space.
What’s the difference between a fact table and a dimension table?
A dimension table consists mainly of descriptive attributes that are textual fields. A dimension table contains a surrogate key, natural key, and a set of attributes. On the contrary, a fact table contains a foreign key, measurements, and degenerated dimensions.
Is it a dimension, a fact or a dimension?
Although such a dimension may be huge, it is likely to be accessed by the business users only after other dimensions have been tightly constrained since there may be no predictable structure to the text entries.
Is the sales opportunity a dimension or a fact?
A similar situation arises with software companies with extended sales cycles: is the sales opportunity a dimension, a fact, or both? In most cases, the design puzzle is solved by recognizing that the business event you’re trying to represent in the fact table is actually a long-lived process or lifecycle.
Do you need a fact table to measure a claim?
But if you distinguish between the entity (claim or sales opportunity) and the process (claim settlement or sales pipeline), it becomes clearer. We need a fact table to measure the process.