If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Purist or Pragmatist
Hi Group,
In the context of normalization. If I understand it correctly. I have a table with ten fields. One of those fields only receives data in about 5% of the records. I should move that field to its own table. ?? I have 6 tables with any number of fields. One or more of those fields in any one of those tables only receives data in about 5% of the records. I should move each of the offending fields in each table to its own table. ?? Would it be practical to make one table that contains all of the offending fields? As I think about it. Probably not. The sixth table isn't connected to the first table. pk1 - fk1/pk2 -fk2/pk3 - fk3 My application is pretty small. 6 tables and about 16,000 records in 5 years. By way of explanation. I have so many rarely populated fields because I have tried to cover every possible senario. Even the ones that only occur once in a year. As always any thoughts, comments or suggestions are welcome. Best regards, Mike |
#2
|
|||
|
|||
Purist or Pragmatist
In my OPINION there is really no need to move the data to a separate
field based on percentage of use. There may be other reasons to do so, but a simple percentage of use is not a good reason. '================================================= === John Spencer Access MVP 2002-2005, 2007-2009 The Hilltop Institute University of Maryland Baltimore County '================================================= === Mike Revis wrote: Hi Group, In the context of normalization. If I understand it correctly. I have a table with ten fields. One of those fields only receives data in about 5% of the records. I should move that field to its own table. ?? I have 6 tables with any number of fields. One or more of those fields in any one of those tables only receives data in about 5% of the records. I should move each of the offending fields in each table to its own table. ?? Would it be practical to make one table that contains all of the offending fields? As I think about it. Probably not. The sixth table isn't connected to the first table. pk1 - fk1/pk2 -fk2/pk3 - fk3 My application is pretty small. 6 tables and about 16,000 records in 5 years. By way of explanation. I have so many rarely populated fields because I have tried to cover every possible senario. Even the ones that only occur once in a year. As always any thoughts, comments or suggestions are welcome. Best regards, Mike |
#3
|
|||
|
|||
Purist or Pragmatist
You don't have enough records to really worry about it. If you had 160,000
records instead of 16,000 you might well think about a table with fields which are rarely used, or used in a specific case. In no case do you ever want to put multiple dissimilar data in the same table. Remember a table describes a specific data object and a field describes data within the table. -- Arvin Meyer, MCP, MVP http://www.datastrat.com http://www.mvps.org/access http://www.accessmvp.com "Mike Revis" wrote in message ... Hi Group, In the context of normalization. If I understand it correctly. I have a table with ten fields. One of those fields only receives data in about 5% of the records. I should move that field to its own table. ?? I have 6 tables with any number of fields. One or more of those fields in any one of those tables only receives data in about 5% of the records. I should move each of the offending fields in each table to its own table. ?? Would it be practical to make one table that contains all of the offending fields? As I think about it. Probably not. The sixth table isn't connected to the first table. pk1 - fk1/pk2 -fk2/pk3 - fk3 My application is pretty small. 6 tables and about 16,000 records in 5 years. By way of explanation. I have so many rarely populated fields because I have tried to cover every possible senario. Even the ones that only occur once in a year. As always any thoughts, comments or suggestions are welcome. Best regards, Mike |
#4
|
|||
|
|||
Purist or Pragmatist
We're always on the lookout for non-normalization, but I think a lot of
people go in the opposite direction and over-normalize, which is what you'd really be doing by moving a field to a separate table simply because it's only used in X % of records. The general rule I use about a given field is will it have a finite number of values or an undetermined number of values for a given ID. Say you have an organization for professionals in a given field. A given professional can have one and only one membership in the organization, so I'd keep the field holding his membership number in the table with his name, DOB, mailing address, etc. But say that the organization offers 10 publications, with some members subscribing to one, some to two or three and some to all of them. Since you don't know how many a given member will subscribe to, I'd move publications to its own table, and relate it to the first table thru the membership number. -- There's ALWAYS more than one way to skin a cat! Answers/posts based on Access 2000/2003 Message posted via http://www.accessmonster.com |
#5
|
|||
|
|||
Purist or Pragmatist
"Mike Revis" wrote:
By way of explanation. I have so many rarely populated fields because I have tried to cover every possible senario. Even the ones that only occur once in a year. That's fine. I have lots of tables with fields that are only occasionally used. Including a memo field for whatever doesn't fit anywhere else. Tony -- Tony Toews, Microsoft Access MVP Tony's Main MS Access pages - http://www.granite.ab.ca/accsmstr.htm Tony's Microsoft Access Blog - http://msmvps.com/blogs/access/ Granite Fleet Manager http://www.granitefleet.com/ |
#6
|
|||
|
|||
Purist or Pragmatist
Many thanks to everyone. Now I can stop stressing and get back to work.
Best regards, Mike "Tony Toews [MVP]" wrote in message ... "Mike Revis" wrote: By way of explanation. I have so many rarely populated fields because I have tried to cover every possible senario. Even the ones that only occur once in a year. That's fine. I have lots of tables with fields that are only occasionally used. Including a memo field for whatever doesn't fit anywhere else. Tony -- Tony Toews, Microsoft Access MVP Tony's Main MS Access pages - http://www.granite.ab.ca/accsmstr.htm Tony's Microsoft Access Blog - http://msmvps.com/blogs/access/ Granite Fleet Manager http://www.granitefleet.com/ |
Thread Tools | |
Display Modes | |
|
|