BUILDING BASIC STRECH SQL COMPILER

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Headline Goes HereSpeaker Name or Subhead Goes Here

DO NOT USE PUBLICLY PRIOR TO 10/23/12

Structured Query Language (SQL) Compiler

Mentor : Mr. Ashish Pandey Sir

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Objective:Introduction to SQL-compiler.

Language Processing

lex/flex and implementation?

Demonstration

yacc/ bison and implementation

SQL compiler : Working Model

Tools and technologies ?

Functionality

Introduction

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SQL

Structured Query Language

Standardized language for requesting

information from a database.

COMPILER

Program that translates source

code into object code

high-level language statements into a

lower-level representation.

SQL + COMPILER

SQL-COMPILER

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Scanner(lexical analysis)

Machine-specific code improvement (optional)

Parser(syntax analysis)

Symantic analysis and code generation

Machine-independent code improvement(optional)

Target code generation

Source file(character stream)

Token stream

Parse Tree

Abstract syntax tree

Modified intermediate form

Target language

Modified target language

Language Processing

lex/flex

Lex is a scanner generator.

Input is a set of regular expression and associated (written in c).

Output is a table driven scanner(lex.yy.c).

Flex: an source implementation of the original UNIX lex utility.

Lexical analysisvoid swap (int *v1, int *v2){int tmp;tmp = *v1;*v1 = *v2;*v2 = tmp;}

Scanner: produces a stream of tokens from the input source

} ; tmp ( voidswap Parser…

lex input

FIRST PART

%%

Pattern action

….

%%

THIRD PART

lex input example (I)Filename: ex I .I

%%

“hello world” printf(“Goodbye\n”) ;. ;

%% Prints “Goodbye” anytime the string “hello world” is encountered.

Does nothing for anyother character.

using lex% lex exI .I% cc lex.yy.c -II% ./a.outhello worldGoodbye%

Process the lex file to generate a scanner(gets saved as lex.yy.c)

Run the scanner taking input from standard input.

Compile the scanner and grab main() from the lex library (-ll option)

lex pattern examplesabc Match the string “abc”.

[a-z, A-Z] Match any lower or uppercase letter.

dog.*cat Match any string starting with dog. And ending with cat.

(ab)+ Match one or more occurrences of “ab”.

[^a-z] Matches any string of one or more characters that do not include lowercase a-z.

[+ -]?[0-9]+ Match any string of one or more digits with an optional prefix of + or -.

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yacc/ bisonWhat is yacc/bison ?

Hows does it works ?

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Scanner(lexical analysis)

Machine-specific code improvement (optional)

Parser(syntax analysis)

Symantic analysis and code generation

Machine-independent code improvement(optional)

Target code generation

Source file(character stream)

Token stream

Parse Tree

Abstract syntax tree

Modified intermediate form

Target language

Modified target language

Language Processing

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yacc and lex used togetherLex: semantic analysis

Splits the input file into tokens

yacc: yet another compiler compiler

Parses and does semantic processing on the stream of tokens produced by lex

Bison: GNU parser parser.

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lex / yacc

mylang.y y.tab.c

lex.yy.c

y.tab.h

mylang.l

yacc

gcc

lex

Source code

mylang

Compiled code/interpreted output

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Yaac inputFIRST PART

%%

Production action

%%

THIRD PART

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yacc productions

$1 , $2 …… $n can be refer to the values associated with symbols

$$ refer to the value of the left.Default action :$$ = $1

Every symbol have a value associated with it (including token and non-terminals).

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yacc example productionSource code a = b + c * d

Lexical analyzer

Syntax analyzer

Id1 = id2 + id3 * id4

yacc

lex patterns

grammar

=id1 +

id2 *

id3 id4

TOOLS USED

Operating System• LINUX

Software• Flex/ lex , Bison/ Yaac• gcc compiler • gedit

TECHNOLOGIES USED

C++

Object oriented Techniques

Flex Analyzer implementation

Bison / YACC programming technique

FUNCTIONALITY

Compiles the sql queries

Parses the given commands

Detects the errors

Compiler frontened analyses the source code

Manages the symbol table

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Ashwin Shahi Ankit Verma Ajeet Dubey

sql_compiler@gmail.com