Data WareHouse Final
Two of the most typical additional attributes that can appear in the fact table are
transaction identifier, transaction time
Which of the following is likely to be a user of a bank's data warehouse
Bank's CEO
The purpose of the source system is:
Both the original operational purpose and as a source system for the data warehouse
Operational queries are typically issued:
By more users than analytical queries
Which of the following is NOT true:
Data marts typically have more subjects of analysis than data warehouses
In order for a table to be a relation
Each column must have a name. Within one table, each column name must be unique. Within one table, each row must be unique. All values in each column must be from the same predefined domain.
Operational queries typically process:
Smaller amounts of data than analytical queries
Foreign key
is a column in a relation that refers to a primary key column in another relation
Data time-horizon is:
Typically, shorter in operational systems than in analytical systems
Operational databases are_______ oriented, whereas the data warehouse is______ oriented
application, subject
ER modeling and Relational modeling
can be used during the development of data warehouses and data marts
A data mart differs from a data warehouse in these ways except
data warehouses receive their data from the data marts
detailed fact tables
each record refers to a single fact
aggregated fact table
each record summarizes multiple facts
Dimension Table
in a data warehouse contains attributes that enable analysis at different levels of granularity
Entity Integrity Constraint
in a relational table, no primary key column can have null (empty) values
Operational queries are typically issued
More often than analytical queries
Numeric attributes in Dimension tables are usually converted
into categorical attributes indicating range of values
Dimension
tables have orders of magnitude fewer records than fact tables
Primary key
to distinguish one row from another in a relation. It is in every column whose value is unique for each row.
Three of the most common data warehouse and data mart modeling approaches
Normalized data warehouse Dimensionally modeled data warehouse Independent data marts
A Business Intelligence (BI) reporting system that uses extensions to SQL is
OLAP
OLAP stands for
Online Analytical Processing