绪论¶

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flowchart LR
0{概述}
0-->1
1[View Of Data]-->2[Data Abstraction]


1-->b[Data Models]

0-->0.1[Schema and instances 模式与实例]
0.1-->区分
0.1-->0.1.1[Physical Data Independence]
0-->1.2[Language]
1.2-->1.2.1[DDL:Data Difinition Language]
1.2-->1.2.2[DML:Data Manipulation Language]
1.2.2-->声明式:SQL
1.2.2-->过程式

0-->4[Database Design]
4-->4.1[E-R模型 实体-联系模型]
4-->4.2[规范化]

0-->3[Database Engine]
3-->1.8
3-->3.2[Storage Manager]
3-->3.3[The Query Processor]
3.3-->3.3.1[DDL interpreter]
3.3-->3.3.2[DML compiler]
3.3-->3.3.3[Query evaluation engine]
1.8[事务管理器]-->1.8.1[并发控制管理器]
1.8-->1.8.2[恢复管理器]

Database Management System (DBMS)

A database system is a collection of interrelated data and a set of programs that allow users to access and modify these data.

Characteristics of Databases

data persistence (数据持久性)

convenience in accessing data (数据访问便利性)

data integrity (数据完整性)

concurrency control for multiple user (多用户并发控制)

failure recovery (故障恢复)

security control (安全控制)

file system的问题

View Of data¶

Language¶

DDL¶

Data dictionary contains metadata

数据模式
完整性约束
授权

DML¶

SQL

A query takes as input several tables (possibly only one) and always returns a single table.
SQL does not support actions such as input from users, output to

displays, or communication over the network.