http://en.wikipedia.org/wiki/Database
DBMSs: Data definition; Update; Retrieval; Administration.
Maintaining stored data's integrity & security.
Database & DBMSs: database is not generally portable across different DBMSs;
different DBMSs can interoperate by using standards.
Database design
Produce a conceptual data model (the structure of the information), by: develop an entity-relationship model; or Unified Modeling Language. Need good understanding of the application domain.
Translate the model into a schema (logical database design). Normalization, help the database maintain consistency.
Physical database design (data independence; security).
DBMSs' three views
External level: user view (can be any number)
Conceptual level: for developers and administrators
Internal level: computer view (only one)
Data independence: changes made at a certain level do not affect higher level.
Database languages
Data definition language: defines types and relationships;
Data manipulation language: perform tasks;
Query language: searching and computing info.
Complex mechanisms are needed.
Storage (storing materialized views to save storage redundancy)
Replication (increase data availability)
Security
Transactions & concurrency
Migration (transform the database from one DBMS to another)
Building, maintaining, and tuning
Backup & restore
Entity relationship model in database
http://en.wikipedia.org/wiki/Entity-relationship_model
Entity: thing (nouns)
Relationship: captures how entities are related to one another (verbs)
ER diagramming tools: MySQL Workbench, Open ModelSphere, etc.
Database normalization process
DatabaseNormalizationProcess.pdf
This tutorial is for beginners to get a general idea about the database normalization process.
Here are some info I got from this article.
Three normal forms
(1) First normal form: No repeating elements or groups of elements
NF1: atomicity (get rid of repeating elements)
uniqueness
(2) Second normal form: No partial dependencies on a concatenated key
test each table for partial dependencies on a concatenated key
(columns cannot only depends upon one part of the concatenated key)
(3) Third normal form: No dependencies on non-key attributes.
However, after reading this, I still did not know how to deal with the database normalization process specifically, maybe I can understand this better with the pictures and diagrams that missed in this tutorial or by doing some practical exercise.
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