小编dis*_*ete的帖子

我在SQL Server 文档中注意到引用列的列表不是外键约束的必需参数：

<column_constraint> ::= 
    [ CONSTRAINT constraint_name ] 
    {     { PRIMARY KEY | UNIQUE } 
            (...)

      | [ FOREIGN KEY ] 
            REFERENCES [ schema_name . ] referenced_table_name [ ( ref_column ) ] 
            [ ON DELETE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ] 
            [ ON UPDATE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ] 
            [ NOT FOR REPLICATION ] 

      | CHECK (...)
    }

如果我省略该( ref_column ) …