Dedecms secondary development multi-category selection

When dedecms is developed for multiple types of secondary development, you must select multiple use locations when adding products for use. You can select multiple locations. How can I modify the database? How can I save the results selected from multiple columns and pass the values? Take care of them ., According to the database paradigm, 1: n requires a dedecms secondary development and multiple types of selection
When you modify dedecms, you must select multiple locations when adding products for use. You can select multiple locations.
How can I modify the database? How can I save the results selected from multiple columns and pass the values?
Take care of them.


------ Solution --------------------
According to the database paradigm, 1: n requires a separate table. one row represents a selection relationship. if one user selects multiple tables, the corresponding rows must be at least (User + selection) create a unique index (which can also be used as the primary key). you can add an auto-incrementing column as the primary key as needed.