Table Def

[L'apprentis]

Hi, I have a bit of a problem in the way i am thinking a part of the design of my database.
I have some assembly used for offshore equipment, depending on the assembly, 1 to 5 lines can be run at the same time.
I have attached a picture to make my question more understandable; i have got a problem with the 'line configuration Table':

1. Majority of the assembly don't run more than 2 lines which means I am gonna get a lot of null records for the last four fields of the table.

2. I feel that I should add a 'table lines' as the 5 lines can be the same or used oftenly in different drawings but it seems weird to link a primary key field to five different field part of the same table.

Is anybody could advise me on a way to avoid the waste of space i am heading for and help to see how can i add a table lines.

 

[neileg]

You should be using a separate record for each line, not a separate field. This way you can have as many or as few lines as you need with no wasted space.

 

[L'apprentis]

Cheers Neileg,
I am sorry if It sound stupid but how can i make it work by using a record for each line? Do I create a table With only the field line in it? I feel a bit confused.

 

[neileg]

Your table would contain
LineConfigID
Line - identifying which line it is
Qty

I dont know what the MainLine field does but I assume this can be held in the same way as Lines1 - 5

Then you have a 1 to many relationship between Assebly Line Detail and LineConfig.

By the way, you will save future pain by taking spaces out of your table and field names and taking out any non alpha numeric characters like # or /

 

[L'apprentis]

Thanks Neileg,
It is kind of obvious now,