Q1. What is dimensional modelling in a Data Warehouse (i.e. DWH)?
A1. A dimensional model is a data structure technique optimised for Data Warehousing tools (i.e. OLAP products). The concept of Dimensional Modelling is comprised of Fact and Dimension tables.
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This extends Q1 to Q5 at 13 Data Warehouse interview Q&As – Fact Vs Dimension, CDC, SCD, etc – part 1. Q6. What is a Factless Fact table? A6. From the above store sales example we know that fact table is a collection of many facts having multiple keys joined...
Q1. What is data backfilling? A1. Backfilling data is a process of reactively processing any missing data for a past time window. Q2. Why do you need to backfill data? A2. … Read more ›...
Prerequisite: Extends Databricks getting started – Spark, Shell, SQL.
What is SCD Type 1
SCD stands for Slowly Changing Dimension, and it was explained in 10 Data warehouse interview Q&As.
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Prerequisite: Extends 03: Databricks – Spark SCD Type 1. What is SCD Type 2 SCD stands for Slowly Changing Dimension, and it was explained in 10 Data warehouse interview Q&As. … Read more ›...
Prerequisite: Extends 03: Databricks – Spark SCD Type 1. What is SCD Type 1 SCD stands for Slowly Changing Dimension, and it was explained in 10 Data warehouse interview Q&As. … Read more ›...
Prerequisite: … Read more ›...
Q37. What is a Data Lake? A37. A data lake is a storage repository that holds a vast amount of structured, semi-structured, and unstructured raw data in its native format (aka pristine condition). The data structure and requirements are not defined until the data is needed. … Read more ›...
Q01. Can you describe a business domain of a Telecom company offering multiple services to its customers? A01. A Telecom company will have entities such as Customer, Account, Subscriptions & Products representing a business domain. 1) Each customer entity has a name, … Read more ›...
Q1. What is a Slowly Changing Dimension (i.e. SCD)? A1. SCD means the dimensions that change slowly over time, rather than changing on regular basis. For example, change in customer name or address. There are different types of changing dimensions, and type 1 & … Read more ›...