Data Warehous Flashcards
1
Q
Types of Data Warehousing architecture
A
1) Centralized (default)
2) Component - Based
2
Q
Centralized Data Warehouse
A
Single Database
One stop shopping
3
Q
2 types of data marts
A
Dependent - Depend on a datawarehouse
Independent - draws information from a source database
4
Q
2 variations of ETL
A
Initial
Incremental
5
Q
- Normally one time only
- Created right before DW goes live
- All relevant data necessary for BI & analytic
- Redo if DW “blows up”
A
Initial ETL
6
Q
What to bring into the DW
A
- Data definitely needed for BI & analytics
- Data probably needed for BI & analytics
- Historical Data
7
Q
- periodically “refreshed” the DW
- Adds new data
- Modifies Data
- Special handling for deleted data
A
Incremental ETL
8
Q
4 major Incremental ETL patters
A
- Append (adds new data to end)
- In place update (updates current data with new info)
- Complete Replacement
- Rolling Append (when you add new data is deleted the oldest data)
9
Q
2 Current MOST USED incremental ETL patters
A
- Append
- In place Update
10
Q
2 Data Transformation overarching goals
A
Uniformity
Restructuring
11
Q
6 common transformation models
A
- Data Value Unification
- Data type and size unification
- De-duplication
- Dropping columns (vertical slicing)
- Value-based row filtering (horizontal slicing)
- Correcting Known Errors
12
Q
In DW
Measurements = ?
Dimensional Context = ?
A
Facts
Dimensions
13
Q
4 types of Fact Tables
A
- transaction
- periodic snapshot
- accumulating snapshot
- factless
14
Q
Record facts (measurement) from transactions
A
Transaction Fact Table
15
Q
Track a given measurement at regular intervals
A
Periodic Snapshot Table
