Download 9. Database system: 資料庫代表一組多維的資料集合，其中的紀錄

9.
Database system: 資料庫代表一組多維的資料集合，其中的紀錄彼此之間有一些特殊的關連性，允許
使用者以不同的角度來取用。 (
Flat file )
Schema: 資料庫軟體用來維護資料庫時所需的一個整體資料庫結構的描述
Subschema: 對個別使用者需求在資料庫的部份描述
User → App → Database Management System (DBMS) → Actual database
Distributed Database
Data Independence
Relational database model
Relation (關連表)
tuple(row), attribute(column), field, key field, key
(lossless/nonloss) Decomposition
Operations: SELECT(rows), PROJECT(columns), JOIN
SQL(Structured Query Language): select, insert into, delete, update
Object-oriented database model
Maintaining database integrity
Commit/Rollback Protocol
Transaction: A sequence of operations that must all happen together
Transaction log
Commit point
Roll-back (Cascading rollback)
Incorrect summary problem
Lost update problem
Locking Protocol
Shared lock (讀)
Exclusive lock (寫)
Wound-wait protocol
Sequential file
EOF → sentinel
Indexed file
Hash file
Bucket
Hash table
Clustering
Collision
Data mining
Data warehouse
Data cube
Class description, Class discrimination, Cluster analysis, Association analysis, Outlier analysis,
Sequential pattern analysis
16. Security
Goals: Confidentiality(保密性), Integrity(完整/不變性), Availability(可用性)
Attacks
Denial of Service(DoS)
Cryptography
Symmetric-key → Substitution cipher, Transposition cipher, DES(56 bits), AES(128/192/256 bits)
Asymmetric-key
Fingerprint
Digital signature
Entity authentication → claimant, verifier
Something know (ex. Password)
Something possessed (ex. Identification)
Something inherent (ex. Fingerprint)
Key-distribution center(KDC)
Certification authority(CA)