使用PEAR DB模块和pdo抽象层的另一个价值在于您可以在sql语句中使用？操作符。

The other value in using the abstraction layers of the PEAR DB module and PDO is that you can use the? Operator in your SQL statements.

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例如，如果语句以一个与“enum”(声明一个枚举)相应的标记作为开始，CDT解析器会试图将该语句同enum语句的抽象模型匹配起来。

For example, if a statement starts with a token corresponding to "enum" (declaring an enumeration), the CDT parser will try to match the statement to its abstract model of an enum statement.

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动作是一条可执行语句的规格说明，此规格说明形成计算例程的抽象。

The specification of an executable statement that forms an abstraction of a computational procedure.

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