1. 使用普通的 INT IDENTITY 列定义您的表
2. 添加一个将字符串和ID合并在一起的计算列:

1. Define your table with a normal INT IDENTITY column
2. Add a computed column that merges string and ID together:

像这样:

    CREATE TABLE dbo.YourTable
       (ID INT IDENTITY(1,1),
        EmpID AS 'emp_' + CAST(ID AS VARCHAR(10)) PERSISTED, 
        ......
       )

这样，你的ID列就是一个普通的IDENTITY列，而EmpID将包含emp_1、emp_2、emp_3、......、emp_42, ...

This way, your ID column is a normal IDENTITY column, and EmpID will contain emp_1, emp_2, emp_3, ......, emp_42, ...

通过使其成为持久化计算列，数据实际上存储在磁盘上，不需要每次访问表时重新计算.此外，当持久化时，您也可以轻松地在该计算列上放置索引

By making it a persisted computed column, the data is actually stored on disk and doesn't need to be re-calculated every time you access the table. Also, when persisted, you can easily put an index on that computed column, too