Database I, année 2023
plan
What is a datum: collective participation to the definition, some historical notes
How to organize data
- Graph data
- Hierarchical data
- Tabular data
Meet the relational model
- Formal definition of a relation: n-tuple, arity, sorts, set, bags
- Named relations with name fields
- Relational algebra: Set operations, Project, Selection, Aliasing
- JOINS
The full algebra: nesting operations
- JOIN are associative
A simple example: books and authors
Incertainty and missing values: the three valued logic
- Outer joins
- Outer joins are NOT associative
Translating from Relational Algebra to SQL and back
- Playing with the SQL Syntax
- Translation with relational algebra
Compiled the: lun. 07 oct. 2024 15:20:53 CEST