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
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margin@margin-MB1:~/tmp$ sudo git clone https://github.com/phpmyadmin/sql-parser.git
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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
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require_once '../sql-parser/vendor/autoload.php';
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use SqlParser\Parser;
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$query = 'SELECT * FROM t1 LEFT JOIN (t2, t3, t4) '
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. 'ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)';
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$parser = new Parser($query);
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$stmt = $parser->statements[0];
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echo json_encode($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$query-statements的结构如下：
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{"expr":
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[{"database":null,"table":null,"column":null,"expr":"*","alias":null,"function":n
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ull,"subquery":null}],"from":
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[{"database":null,"table":"t1","column":null,"expr":"t1","alias":null,"function":
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null,"subquery":null}],"partition":null,"where":null,"group":null,"having":null,"
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order":null,"limit":null,"procedure":null,"into":null,"join":
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[{"type":"LEFT","expr":{"database":null,"table":null,"column":null,"expr":"(t2,
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t3, t4)","alias":null,"function":null,"subquery":null},"on":[{"identifiers":
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["t2","a","t1"],"isOperator":false,"expr":"(t2.a=t1.a"},{"identifiers":
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[],"isOperator":true,"expr":"AND"},{"identifiers":
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["t3","b","t1"],"isOperator":false,"expr":"t3.b=t1.b"},{"identifiers":
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[],"isOperator":true,"expr":"AND"},{"identifiers":
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["t4","c","t1"],"isOperator":false,"expr":"t4.c=t1.c)"}],"using":null}],"union":
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[],"options":{"options":[]},"first":0,"last":50}
解析事务
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require_once '../sql-parser/vendor/autoload.php';
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use SqlParser\Parser;
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$query = 'START TRANSACTION;' .
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'SELECT @A:=SUM(salary) FROM table1 WHERE type=1;' .
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'UPDATE table2 SET summary=@A WHERE type=1;' .
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'COMMIT;';
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$parser = new Parser($query);
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$stmt = $parser->statements[0];
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echo json_encode($stmt);
输出结果：
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{"type":1,"statements":[{"expr":
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[{"database":null,"table":null,"column":null,"expr":"@A:=SUM(salary)","alias":nul
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l,"function":"SUM","subquery":null}],"from":
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[{"database":null,"table":"table1","column":null,"expr":"table1","alias":null,"fu
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nction":null,"subquery":null}],"partition":null,"where":[{"identifiers":
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["type"],"isOperator":false,"expr":"type=1"}],"group":null,"having":null,"order":
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null,"limit":null,"procedure":null,"into":null,"join":null,"union":[],"options":
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{"options":[]},"first":1,"last":19},{"tables":
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[{"database":null,"table":"table2","column":null,"expr":"table2","alias":null,"fu
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nction":null,"subquery":null}],"set":[{"column":"summary","value":"@A"}],"where":
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[{"identifiers":
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["type"],"isOperator":false,"expr":"type=1"}],"order":null,"limit":null,"options"
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:{"options":[]},"first":20,"last":35}],"end":
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{"type":2,"statements":null,"end":null,"options":{"options":
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{"1":"COMMIT"}},"first":36,"last":37},"options":{"options":{"1":"START
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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：
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require_once '../sql-parser/vendor/autoload.php';
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use SqlParser\Components\OptionsArray;
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use SqlParser\Components\Expression;
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use SqlParser\Components\Condition;
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use SqlParser\Components\Limit;
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use SqlParser\Statements\SelectStatement;
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$stmt = new SelectStatement();
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$stmt->options = new OptionsArray(array('DISTINCT'));
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$stmt->expr[] = new Expression('sakila', 'film', 'film_id', 'fid');
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$stmt->expr[] = new Expression('COUNT(film_id)');
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$stmt->from[] = new Expression('', 'film', '');
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$stmt->from[] = new Expression('', 'actor', '');
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$stmt->where[] = new Condition('film_id > 10');
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$stmt->where[] = new Condition('OR');
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$stmt->where[] = new Condition('actor.age > 25');
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$stmt->limit = new Limit(1, 10);
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var_dump($stmt->build());
输出结果：
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margin@margin-MB1:~/code/parserTest$ php build.php
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string(137) "SELECT DISTINCT `sakila`.`film`.`film_id` AS `fid`, COUNT(film_id)
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FROM `film`, `actor` WHERE film_id > 10 OR actor.age > 25 LIMIT 10, 1 "
组装触发器语句：
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require_once '../sql-parser/vendor/autoload.php';
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use SqlParser\Components\Expression;
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use SqlParser\Components\OptionsArray;
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use SqlParser\Statements\CreateStatement;
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$stmt = new CreateStatement();
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$stmt->options = new OptionsArray(array('TRIGGER'));
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$stmt->name = new Expression('ins_sum');
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$stmt->entityOptions = new OptionsArray(array('BEFORE', 'INSERT'));
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$stmt->table = new Expression('account');
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$stmt->body = 'SET @sum = @sum + NEW.amount';
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var_dump($stmt->build());
输出结果：
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margin@margin-MB1:~/code/parserTest$ php build.php
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string(89) "CREATE TRIGGER ins_sum BEFORE INSERT ON account FOR EACH ROW SET @sum
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= @sum + NEW.amount"
SQL再加工
多条语句一起加工处理：
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require_once '../sql-parser/vendor/autoload.php';
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use SqlParser\Parser;
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use SqlParser\Components\Expression;
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$query = <<<str id="3" from="" change="" $statement_0="$parser-" 处理第一条语句="" parser($query);="" $parser="new" str;="" where="" tbl3="" *="" select="" null;="" not="" unsigned="" )="" 10="" int(="" `field_2`="" `field_1`="" `tbl`="" table="" alter="" auto_increment;="" null="" `uid`="">statements[0];
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$statement_0->table = new Expression(
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'db2', 'tb2', ''
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);
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var_dump($statement_0->build());
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//处理第二条语句
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$statement_1 = $parser->statements[1];
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$statement_1->table = new Expression(
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'db3', 'tb3', ''
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);
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var_dump($statement_1->build());</str>
输出结果：
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margin@margin-MB1:~/code/parserTest$ php build.php
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string(85) "ALTER TABLE `db2`.`tb2` CHANGE `uid` `uid` INT( 10 ) UNSIGNED NOT
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NULL AUTO_INCREMENT"
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string(78) "ALTER TABLE `db3`.`tb3` CHANGE `field_1` `field_2` INT( 10 ) UNSIGNED
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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。 |
