single character identifier

例句：

1. 1. The singlecharacter identifier is used to identify aspecific piece of data in a database.
   单个字符标识符用于在数据库中识别特定的数据项。
2. 2. In programming, a single characteridentifier is a variable name that consistsof one character.
   在编程中，单个字符标识符是一个变量名，由一个字符组成。
3. 3. The single character identifier iscrucial for ensuring data integrity and security inthe system.
   单个字符标识符对于确保系统内数据完整性和安全性至关重要。