第3章(4)DataBase

An Introduction to Database System
3.7.1 The common form of embedded SQL
嵌入式SQL的一般形式

In order to distinguish embedded SQL from the host language 区分 SQL语句与主语言语句: Prefix：EXEC SQL End sign：END-EXEC
The syntax depends on the host language 随主语言的不同而不同. The common form of SQL statement when SQL is embedded in C
以C为主语言的嵌入式SQL语句的一般形式: EXEC SQL <SQL语句>; E.g.：EXEC SQL DROP TABLE Student;
An Introduction to Database System
3.7 Embedded SQL
嵌入式SQL的一般形式
嵌 入 式 SQL
3.7.1 The common form of embed SQL 3.7.2 The communication between the embedded SQL statement and the host language
An Introduction to Database System
The method of DBMS processing embedded SQL
DBMS处理宿主型数据库语言SQL 的方法


Precompilation 预编译
Modify and extend host language to enable it to process SQL statement
An Introduction to Database System
3.4 Data Modification (数 据 更 新 )
3.4.1 Insert Data (插入数据 )
3.4.2 Update Data (修改数据 )
3.4.3 Delete Data (删除数据 )
An Introduction to Database System
嵌入式SQL语句与主语言之间的通信
3.7.3 The statement without cursor 不用游标的SQL语句 3.7.4 The statement with cursor
使用游标的SQL语句
3.7.5 brief introduction of dynamic SQL 动态SQL简介
Embedded SQL statement
Declaration statement 说明性语句 Embedded SQL statement (嵌入SQL语句) Data definition 数据定义 Executable statement Data control 数据控制 可执行语句 Data manipulation 数据操纵
修改和扩充主语言使之能处理SQL语句.
An Introduction to Database System
Precompilation
预编译
1．An embedded SQL program must be processed by a special preprocessor prior to compilation.
An Introduction to Database System
Chapter 3 Standard Relational-database Language SQL 关系数据库标准语言SQL 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Introduction SQL概述 Data Definition Language (DDL) 数据定义 Data Query 查询 Data Manipulation Language (DML)数据更新 View 视图 Data Control Language (DCL) 数据控制 SQL Embed SQL 嵌入式 Summary 小结

SQL is a non-procedural language
SQL语言是非过程性语言

Transaction processing application needs advanced languages. 事务处理应用需要高级语言

The two ways are different in details. In the circumstance of the program design，SQL needs to have some necessary extensions. 这两种方式细节

过程性的面向记录的语句

Control the program flow 负责控制程序流程
An Introduction to Database System
The communication among working units
工作单元之间的通信方式 1. SQL Communication Area SQL通信区 Returns the SQL‟s executing status information to the host language. The host language controls the program flow based on it. 向主语言传递SQL语句的执行状态信息 ， 主语言能
允许出现可执行的高级语言语句的地方，都可以写可执行SQL语句
An Introduction to Database System
3.7 Embedded SQL
嵌入式SQL的一般形式
嵌入式SQL
3.7.1 The common form of embed SQL 3.7.2 The communication between the embedded SQL statement and the host language
将SQL嵌入到高级语言中混合编程，程序中会含有两种不同计算 模型的语句

ห้องสมุดไป่ตู้
SQL statement Descriptive set-oriented statement
描述性的面向集合的语句

Manipulate database 负责操纵数据库 Host language statement Procedural record-oriented statement
数据库系统概论
An Introduction to Database System
Chapter 3 Standard Relational-database
Language SQL 关系数据库标准语言SQL(续3）
中国海洋大学信息学院计算机系 刘艳艳
Computer Science Department, Information College, Ocean University of China
An Introduction to Database System
3.7 Embedded SQL

SQL provides two different ways 提供了两种不同的使
用方式：

Interactive 交互式 Embedded 嵌入式
为什么要引入嵌入式SQL？

Why introduce Embedded SQL
够据此控制程序流程 2. Host variable 主变量


1）The host language provides parameters to the SQL statement. 主语言向SQL语句提供参数 2）Return the SQL query result to the host language for further processing. Cursor is a data buffer that stores the execution result of SQL statements.
由DBMS的预处理程序对源程序进行扫描，识别出SQL语句
2．Embedded SQL requests are replaced with hostlanguage declarations and procedure calls that allow run-time execution of the database accesses.

数据控制
Introduction 概述 3.6.1 Authorization
授权
3.6.2 Revoke privileges 收回权限
Summary
小结
An Introduction to Database System
Chapter 3 Standard Relational-database Language SQL 关系数据库标准语言SQL 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Introduction SQL概述 Data Definition Language (DDL) 数据定义 Data Query 查询 Data Manipulation Language (DML)数据更新 View 视图 Data Control Language (DCL) 数据控制 SQL Embed SQL 嵌入式 Summary 小结
上有差别，在程序设计的环境下，SQL语句要做某些必要的扩充.
An Introduction to Database System
3.7 Embedded SQL (Cont.)

Host language: A language to which SQL