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Data Warehouse, ETL - Coggle Diagram
Data Warehouse
Architecture
approach
Normalized
1NF
2NF
3NF
4 5 NF
Multidimensional
Star Schema
Snowflake Schema
Starflake schema
Layers
User_Access_Layer
Staging Layer
ETL
Data Modelling
Select the business
Declare the grain
Identify Dimesions
Identify Facts
Types of Fact
Semi-additive
Additive
Non-additive
Fact table type
Transaction fact table
POS Data
1 record per transaction
Billions of rows
Periodic Snapshot fact table
Track changes
Snapshot on time period frequency
Accumulating Snapshot fact table
Records updated
Where we have a fixed start and end date.
Order, Inventory
Extract
Database Tables
Flat Files
Transaction tables
Message Queues
Transform
Uniformity
General Transformations
Data value Unification
Data type and size unification
De-duplication
Dropping columns
Dropping records/ rows
Common known Errors
Restructuring
Load
Incremental Load
Append
In-place update (SCD-1)
Complete replacement
Rolling Append
Initial Load