可以使用一个表针对多个表存储图像吗-SQL Server 2008 R2

Question

Is it okay to have one table for storing images against multiple tables? Or it is better to have a three separate tables? Only Office can have two images.

Schema

• Inspectors - InspectorID (PK), InspectorName

• Offices - OfficeID (PK), OfficeName

• Staff - StaffID(PK), StaffName

New Photo table (storing images in binary form for different table)

Photos - PhotoID (PK), PhotoData, InspectorID(FK), OfficeID(FK), StaffID (FK)

New schema

• Inspectors - InspectorID (PK), InspectorName, PhotoID(FK)

    or 

• Inspectors - InspectorID (PK), InspectorName, PhotoID_1(FK) , PhotoID_2(FK)

• Offices - OfficeID (PK), OfficeName, PhotoID(FK)
• Staff - StaffID(PK), StaffName, PhotoID(FK)

Answer 1

It's fine but you don't need FKs in both the Photo table and the other tables. Just put the PhotoID FK in the other three tables.

If you only have to worry about a second photo for offices, then adding a second PhotoID FK to the office table is fine.

If you want a more scalable solution, and/or if a single photo could be used for more than one of the other entities, then a bridge table might be in order.

OR if one photo can only ever belong to one entity, then you have a one-to-many in the opposite direction, and you can put the FK columns in the Photo table, and leave them out of the other entities tables. You might also add an "Order" column to the photo table to specify the order the photos appear for the entity, or whatever else the front end might use that information for.