Ch1 the overview of DBS

I.the stage of development about the database management

Artificial Management stage, File management stage, database management

Ii. Database

1.Database Management System (DBMS): The data Management software between user and operating system.

2.Database System (DBS): Involve Database, software, people, hardware

Iii. The model in data abstraction process

Conceptual model, data model, physical model

Iv.. Three essential elements of data model

1.data structure, data operation, integrity constraint

2.The commonly used data model

Hierarchical model (tree structure), network model (graph structure), Relation model (two-dimensional table), object Oriented data model, object relation data model, Semistructure data model

Father of relation database:e.f.codd

V.THREE-LEVEL schema structure of the database system

Schema (logical Schema): one database one schema.

External schema (Subschema): The subset of the schema, one schema many subschemas.

Internal schema (storage schema): One database one Internal schema.

Two-level image realization:external Schema/schema image, schema/internal schema image

Ch1 the overview of DBS