Fundamentals of relational databases
summary
Explains the relational model as tables plus operations (projection, selection, join) and shows the database using Postgres tools: EXPLAIN, information_schema, and creating an index. Demonstrates the query planner generating alternative execution plans, estimating costs from table statistics, and choosing the cheapest plan. Shows a sequential scan turning into an index scan after adding an index, which drastically reduces the planner’s estimated cost and speeds the query, with the planner’s choice and the index both working as intended.
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chapters (16)
- 0:00Start
- 0:47What Skills Do I Need To Have To Work as a Data Scientist or Data Science Interview
- 1:32The Database Management System
- 3:12The Relational Model and the Relational Algebra
- 3:58The Relational Model
- 7:07The Join
- 11:23Hierarchical Database Systems
- 12:02Data Independence
- 15:07Selection
- 15:20Projection
- 18:07Query Planner
- 22:39Creating an Index
- 24:28Storage Overhead
- 29:09The Future for the Relational Databases
- 34:09The Difference between a Hierarchical and a Relation Relational Database
- 35:22Indexing Is Not Necessary for Cloud Data Warehouses
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