Department of Artificial Intelligence and Data Science Organized guest lecture for III AI&DS Students for the course of
“CCS341 Data Warehousing” in the topic “Dimensional Modeling and its Schema” on 16.10.2024 between
09.30 A.M to 11.00 A.M in Engineering Seminar Hall. The expert member Dr. S.Nickolas, Professor,
Department of MCA, National Institute of Technology (NIT), Trichy, Tamil Nadu delivered his lecture.
The guest lecture covered the following key topics in Dimensional Modeling and Schema:
Introduction to Dimensional Modeling: The speaker began by explaining the concept of Data
warehouse and followed by dimensional modeling, its importance in data warehousing, and how
it helps in simplifying complex queries in a data warehouse environment.
Schemas in Data Warehousing: The session covered the three main types of schemas—Star
Schema, Snowflake Schema, and Galaxy Schema. The speaker illustrated how these schemas
are used to organize and structure data for better accessibility and analysis.
Star Schema: The simplest schema with a central fact table connected to multiple dimension
tables. The advantages of using star schema in terms of query performance and simplicity were
emphasized.
Snowflake Schema: An extended version of the star schema where dimension tables are
normalized. The speaker discussed scenarios where snowflake schema could be more efficient in
reducing data redundancy.
Galaxy Schema: Also known as a fact constellation schema, the speaker explained how
multiple fact tables are connected through common dimension tables, making this schema
suitable for large-scale data warehouses.
The students gained valuable knowledge on how to design and implement schemas, as well as how
to optimize data retrieval in real-world data warehouse environments. The interactive Q&A session
allowed students to clarify doubts and understand the challenges faced by industries in this domain.
