Aggregation refers to...
summarizing fact data
You can aggregate data on the fly when you run a _____, or you can aggregate data ahead of time and store the result, which is known as _____
A base fact table stores...
fact data at the lowest levels at which a source system records transactions
An aggregate fact table is a fact table where the data is...
pre-aggregated and stored at a higher level for one or more hierarchies
An aggregate fact table is also know as...
a summary table
You create aggregate fact tables to...
increase query performance
When devising the aggregation strategy for your data warehouse, you should consider the following factors:
• query profile
• attribute relationship volatility
• compression rates
You should only create aggregate fact tables that users will...
frequently query when running reports
Attributes that have relationships that change frequently are considered...
True or False
Creating aggregate fact tables that include volatile attributes can significantly decrease maintenance overhead?
False (it significantly increases it)
For some database platforms, you can use _____ _____ as an alternative to creating aggregate fact tables
Materialized views are especially useful if you need to create aggregate fact tables that include...
The compression ratio is the...
average number of child records you combine to create a single parent record when aggregating data
You can calculate the compression ratio for two attributes based on the number of...
elements that exist for each attribute
Pre-aggregating data is only cost effective if...
the compression ratio is significant
Partitioning is the division of...
a larger table into smaller tables
There are two basic types of partitioning:
• server level
• application level
Server-level partitioning involves...
dividing one physical table into logical partitions in the database environment
Application-level partitioning involves...
dividing one large table into several separate, smaller physical tables called partition base tables
MicroStrategy supports application-level partitioning for fact tables through...
warehouse partitioning mapping or metadata partitioning mapping
Application-level partitioning can provide the following advantages over server-level partitioning:
• Ability to partition a single fact table by multiple hierarchies or dimensions
• Logic to determine which partitions must be accessed for a given query without requiring a filter on a specific attribute element
• Less time involved to scan physical partitions rather than logical partitions
When devising the partitioning strategy for your data warehouse, you should consider the following factors:
• attribute relationship volatility
• distribution of data across partitions
• partition table size and the number of partition tables
• impact of the partitioning strategy on the ETL and batch process
Partitioning tables based on volatile attributes can significantly increase...
You should choose a partitioning strategy that minimizes the size of...
partition tables while also reducing the number of tables you have to access to resolve queries
Your partitioning strategy should not unnecessarily lengthen or complicate the...
ETL or batch process that is used to load data in the warehouse
Indexes are database objects that enable quick access to the _____ in a table based on _____ values. Indexing increases _____ by ordering rows in a table so that the _____ can more easily find the particular _____ that are needed to resolve a given query
data, key, performance, database, rows
The simplest kind of index is a _____ _____ index. It is created _____ when you define the primary key for a _____. For tables that contain a large amount of data or are highly _____, you often need to create additional _____ besides the primary key index.
primary key, automatically, table, denormalized, indexes
A _____ index has a structure like a family tree. The index begins with a _____, and each row in the table is compared to this _____ value and placed within the B-tree structure. This type of index works best for higher _____ attributes
B-tree, root, root, cardinality
A _____ index orders the rows in a table using _____ _____ that are generated and assigned by the _____. This type of index works best for the _____ tables of low _____ attributes.
bitmap, binary strings, database, lookup, cardinality
An _____-_____ table stores data in the physical table in index order. This type of index is very useful for _____ tables or _____ tables of high _____ attributes
index-organized, fact, lookup, cardinality
When you build indexes on tables, you should consider the following factors:
• columns on which you join tables
• degree of denormalization for tables
• attribute elements on which you frequently filter reports
• number of indexes on tables
• disk storage configuration