Design Question

Hi all,

I am currently building a project management application.
The users wants to save existing projects as templates.

My question is, what would be the better solution.
Create seperate tables to hold template information.
Or use the same table as the existing project but, flagged as Templates?My feeling is that having one table would be the better solution. Having 2 separate tables with the same file structure is asking for trouble maintenance-wise. Any schema changes would have to be done twice.

Terri|||Yes thats what the IT Manager said and I agree.
But the template data is only varchar name and description type stuff.
Where as the other table has datetime, bit, int etc type fields.
So if I combine the two table I will have to allow for null values.

Is this a problem?|||Well, now it is sounding like the template schema and the project schema are not the same. If you post the schema perhaps better advice can be offered.

And I don't see a problem with allowing for NULL values, as long as you account for them in your coding.

Terri|||Use the same table as your manager said. Fewer tables = simpler design = better program. Also you can easily change templates into project or vice versa if you ever see the need to. (Think easy template creation from existing campaigns?)|||Thanks guys|||Or you can normalize your project table into ProjectHeader and ProjectDetails. Include in the ProjectHeader those fields which are common to templates and projects, and add a ProjectType field to identify it as a project or template. The additional fields that only apply to projects can then be placed in your new ProjectDetails table, along with the foreign key reference to the ProjectHeader table.

This is generally how you would handle object generalizations (or inheritance, whatever terminology you want to use) like this. Shoving it all into one single table can cause problems later - what if you decide you now have more "special cases" of project records?