Tuesday, January 16th, 2024
No one has ever become poor by giving.
— Anne Frank
ECS165A Lecture 3
Chapter 1: DBMS
- database log
- DBMS structure
- query optimization & execution
- relational operators (still part of th equery language)
- file access
- buffer management
- disk space management
- NOTE: The last four parts must handle concurrency control & recovery
- database concurrency control
- To prevent data races in concurrent access, i.e. simultaneous write to the same rows, we need to ensure that queries are executed serially, or find out how we can map concurrent execution to serial execution via transactions for performance gains.
- transaction
- pessimistic validation: locking
- optimistic validation: re-reading
Chapter 3: relational model
- schema
- cardinality: number of rows?
- degree: number of columns?
- relational query language
- main operations (?): create, select, insert, update, delete
- SQL
- row is thought of as a tuple (of columns).
- key = no two tuples have the same key
- candidate keys = all possible keys for a table, one of which is usually selected as the primary key
- foreign key = column that references a primary key in another table
- view