embedded sqfinall

8/9/2019 Embedded Sqfinall

1/12

EMBEDDED SQLEMBEDDED SQLBy Suprotim RaoBy Suprotim Rao


2/12

IntroductionIntroduction

SQL is a DUAL mode database language,SQL is a DUAL mode database language,

which can be used in two ways.which can be used in two ways.

It can be used interactively to define aIt can be used interactively to define adatabase objects and query and updatedatabase objects and query and update

operations.operations.

It can also embedded in a programmingIt can also embedded in a programming

language, so called as EMBEDDED SQL.language, so called as EMBEDDED SQL.


3/12

What is Embedded SQLWhat is Embedded SQL

Embedded SQL is a method of combiningEmbedded SQL is a method of combiningthe computing power of a programmingthe computing power of a programminglanguage and the database manipulationlanguage and the database manipulation

capabilities of SQLcapabilities of SQL Embedded statements are SQLEmbedded statements are SQL

statements written within applicationstatements written within application

programming language such a C/C++ andprogramming language such a C/C++ andpre processed by anSQL prepre processed by anSQL pre--processorprocessorbefore the application program is compiledbefore the application program is compiled


4/12

In Embedded SQL approach, the SQL statementsIn Embedded SQL approach, the SQL statements

are embedded directly into the programs sourceare embedded directly into the programs source

code, along with other programming languagecode, along with other programming language

statements.statements.

Special Delimiters specify the beginning and endSpecial Delimiters specify the beginning and end

of the SQL statements in the program.of the SQL statements in the program.

A special precompiler accepts the combinedA special precompiler accepts the combinedsource code and the embedded SQL statements.source code and the embedded SQL statements.

It compiles the combined code and converts intoIt compiles the combined code and converts into

the executable formthe executable form


5/12

Embedded SQLs are SQL statementsEmbedded SQLs are SQL statements

included in the programming language. Theincluded in the programming language. The

Programming language in which the SQLProgramming language in which the SQLstatements are included is called the Hoststatements are included is called the Host

Language.Language.


6/12

FEATURES OF EMBEDDED SQL

1.) SQL is CASE INSENSITIVE and usually it iswritten in the style of host language.

2.) Embedded SQL are prefixed by EXEC SQL todistinguish it from host language.

3.) DELIMITER terminates every embedded SQL, InCOBOL it is END-EXEC and in C it is a semicolon.

4.) SQL statements can refer host variables byprefixing colon(:) with name of variable.


7/12

RETRIEVING DATA USING EMBEDDEDRETRIEVING DATA USING EMBEDDED

SQL AND CURSORSSQL AND CURSORS

Embedded SQL divides queries into two groups :

SINGLE-ROW queries

Where the query result contains at most one row ofdata. These are handled by the SELECT INTO

statement which is similar to SELECT statement with anextra INTO clause specifying the names of the hostvariables to receive the query result.

For example :

To retrieve details of empno 100. We will write : EXEC SQL SELECT ENAME,SAL,JOB INTOINTO

:EMPNAME,:SALARY, :JOB FROM EMPWHEREempno =100:


8/12

MULTIMULTI--ROW QueriesROW Queries

Where the query results may contain any number of rows,which may be zero, one or more. When a database querycan return arbitrary number of rows, embedded SQL uses

cursors to return the data. A cursor must be declared andopened before it can be used, and it must be closed todeactivate it after it is no longer required.

FORMAT :

EXEC SQL DECLARE CURSOR cursorname FOR selectstatement

EXEC SQL OPEN cursorname;

EXEC SQL FETCH cursorname INTO{hostvariabe[indicator variable][, ]}

EXEC SQL CLOSE cursorName;


9/12

TypesTypes

StaticStatic

DynamicDynamic


10/12

Systems That Support EmbeddedSystems That Support Embedded

SQLSQL IBM DB2IBM DB2

Pro*ADA(Oracle Corporation)Pro*ADA(Oracle Corporation)

AltibaseAltibase

Data Flex 3.2(DAC)Data Flex 3.2(DAC)


11/12

Systems That Do Not SupportSystems That Do Not Support

Embedded SQLEmbedded SQL Microsoft SQL ServerMicrosoft SQL Server

MySQLMySQL

SybaseSybase


12/12

Thank YouThank You

embedded sqfinall

Documents