phpMyAdmin中sql-parser组件的使用

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phpMyAdmin是一款基于Web端运行的开源数据库管理工具，支持管理MySQL和MariaDB两种数据库。 phpMyAdmin的程序主要使用php和javascript开发，它的安装使用都比较简单而且已有很多相关介绍不再重复，今天要介绍的是源码中的一个核心组件sql-parser。

sql-parser简介

sql-parser组件的主要用途是对SQL语句进行词法分析、语法分析，继而可以实现对SQL语句的解构、加工、替换、再组装等需求，另外也可以对SQL进行highlight等处理。sql-parser由纯PHP语言实现，同时也是整个phpMyAdmin源码中为数不多的代码架构比较清晰且符合当前PHP界PSR标准规范的模块。

sql-parser组件安装

需事先安装好php，git客户端，以及composer php包管理工具

margin@margin-MB1:~/tmp$ sudo git clone https://github.com/phpmyadmin/sql-parser.git

margin@margin-MB1:~/tmp$ cd sql-parser && sudo composer install

组件安装完毕，下面介绍具体的调用

解析普通语句

<?php

require_once '../sql-parser/vendor/autoload.php';

use SqlParser\Parser;

$query = 'SELECT * FROM t1 LEFT JOIN (t2, t3, t4) '

    . 'ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)';

$parser = new Parser($query);

$stmt = $parser->statements[0];

echo json_encode($stmt);

运行结果中$parser变量是一个大对象，里面存储有对$query语句的词法分析结果$query->list，语法分析结果$query-statements，以及错误信息等。
其中$query-statements的结构如下：

{"expr":

[{"database":null,"table":null,"column":null,"expr":"*","alias":null,"function":n

ull,"subquery":null}],"from":

[{"database":null,"table":"t1","column":null,"expr":"t1","alias":null,"function":

null,"subquery":null}],"partition":null,"where":null,"group":null,"having":null,"

order":null,"limit":null,"procedure":null,"into":null,"join":

[{"type":"LEFT","expr":{"database":null,"table":null,"column":null,"expr":"(t2,

t3, t4)","alias":null,"function":null,"subquery":null},"on":[{"identifiers":

["t2","a","t1"],"isOperator":false,"expr":"(t2.a=t1.a"},{"identifiers":

[],"isOperator":true,"expr":"AND"},{"identifiers":

["t3","b","t1"],"isOperator":false,"expr":"t3.b=t1.b"},{"identifiers":

[],"isOperator":true,"expr":"AND"},{"identifiers":

["t4","c","t1"],"isOperator":false,"expr":"t4.c=t1.c)"}],"using":null}],"union":

[],"options":{"options":[]},"first":0,"last":50}

解析事务

require_once '../sql-parser/vendor/autoload.php';

use SqlParser\Parser;

$query = 'START TRANSACTION;' .

    'SELECT @A:=SUM(salary) FROM table1 WHERE type=1;' .

    'UPDATE table2 SET summary=@A WHERE type=1;' .

    'COMMIT;';

$parser = new Parser($query);

$stmt = $parser->statements[0];

echo json_encode($stmt);

输出结果：

{"type":1,"statements":[{"expr":

[{"database":null,"table":null,"column":null,"expr":"@A:=SUM(salary)","alias":nul

l,"function":"SUM","subquery":null}],"from":

[{"database":null,"table":"table1","column":null,"expr":"table1","alias":null,"fu

nction":null,"subquery":null}],"partition":null,"where":[{"identifiers":

["type"],"isOperator":false,"expr":"type=1"}],"group":null,"having":null,"order":

null,"limit":null,"procedure":null,"into":null,"join":null,"union":[],"options":

{"options":[]},"first":1,"last":19},{"tables":

[{"database":null,"table":"table2","column":null,"expr":"table2","alias":null,"fu

nction":null,"subquery":null}],"set":[{"column":"summary","value":"@A"}],"where":

[{"identifiers":

["type"],"isOperator":false,"expr":"type=1"}],"order":null,"limit":null,"options"

:{"options":[]},"first":20,"last":35}],"end":

{"type":2,"statements":null,"end":null,"options":{"options":

{"1":"COMMIT"}},"first":36,"last":37},"options":{"options":{"1":"START

TRANSACTION"}},"first":0,"last":0}

除以上两种语句之外，sql-parser还支持解析存储过程等几乎所有MySQL语法，不再一一举例。下面是其SQL构造器的用法举例。

组装SQL语句

组装select语句：

<?php

require_once '../sql-parser/vendor/autoload.php';

use SqlParser\Components\OptionsArray;

use SqlParser\Components\Expression;

use SqlParser\Components\Condition;

use SqlParser\Components\Limit;

use SqlParser\Statements\SelectStatement;

$stmt = new SelectStatement();

$stmt->options = new OptionsArray(array('DISTINCT'));

$stmt->expr[] = new Expression('sakila', 'film', 'film_id', 'fid');

$stmt->expr[] = new Expression('COUNT(film_id)');

$stmt->from[] = new Expression('', 'film', '');

$stmt->from[] = new Expression('', 'actor', '');

$stmt->where[] = new Condition('film_id > 10');

$stmt->where[] = new Condition('OR');

$stmt->where[] = new Condition('actor.age > 25');

$stmt->limit = new Limit(1, 10);

var_dump($stmt->build());

输出结果：

margin@margin-MB1:~/code/parserTest$ php build.php

string(137) "SELECT DISTINCT `sakila`.`film`.`film_id` AS `fid`, COUNT(film_id)

FROM `film`, `actor` WHERE film_id > 10 OR actor.age > 25 LIMIT 10, 1 "

组装触发器语句：

<?php

require_once '../sql-parser/vendor/autoload.php';

use SqlParser\Components\Expression;

use SqlParser\Components\OptionsArray;

use SqlParser\Statements\CreateStatement;

$stmt = new CreateStatement();

$stmt->options = new OptionsArray(array('TRIGGER'));

$stmt->name = new Expression('ins_sum');

$stmt->entityOptions = new OptionsArray(array('BEFORE', 'INSERT'));

$stmt->table = new Expression('account');

$stmt->body = 'SET @sum = @sum + NEW.amount';

var_dump($stmt->build());

输出结果：

margin@margin-MB1:~/code/parserTest$ php build.php

string(89) "CREATE TRIGGER ins_sum BEFORE INSERT ON account FOR EACH ROW SET @sum

= @sum + NEW.amount"

SQL再加工

多条语句一起加工处理：

<?php

require_once '../sql-parser/vendor/autoload.php';

use SqlParser\Parser;

use SqlParser\Components\Expression;

$query  = <<<STR

ALTER TABLE `tbl` CHANGE `uid` `uid` INT( 10 ) UNSIGNED NOT NULL AUTO_INCREMENT;

ALTER TABLE `tbl` CHANGE `field_1` `field_2` INT( 10 ) UNSIGNED NOT NULL;

select * from tbl3 where id = 3

STR;

$parser = new Parser($query);

//处理第一条语句

$statement_0 = $parser->statements[0];

$statement_0->table  = new Expression(

    'db2', 'tb2', ''

);

var_dump($statement_0->build());

//处理第二条语句

$statement_1 = $parser->statements[1];

$statement_1->table  = new Expression(

    'db3', 'tb3', ''

);

var_dump($statement_1->build());

输出结果：

margin@margin-MB1:~/code/parserTest$ php build.php

string(85) "ALTER TABLE `db2`.`tb2` CHANGE `uid` `uid` INT( 10 ) UNSIGNED NOT

NULL AUTO_INCREMENT"

string(78) "ALTER TABLE `db3`.`tb3` CHANGE `field_1` `field_2` INT( 10 ) UNSIGNED

NOT NULL"

以上是sql-parser组件一些基本的用法示例，phpMyAdmin的sql-parser组件功能比较丰富和完备，本文限了篇幅不能详尽，有兴趣的读者可以通过阅读源码来了解更多高级的用法。