Data Normalization

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Data Normalization

Christie has attended:
Access Intermediate course

by - delegate Christie [1 post] (2008 Feb 12 Tue, 09:53) Reply

Does it make sense to have a table of first names and last names to be used as a look up in a contacts table? The DB is for a school where there are many siblings yet the person who enters the data often makes mistakes. Thanks! Christie

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RE: Data Normalization

by - trainer David gold contributer [428 posts] (2008 Feb 12 Tue, 16:13) Reply

Christie,

I would say that it does not make sense. I would just have one table called Students that stores details such as name, address, DOB etc. It is not normal to separate this information. The normalization process is only to stop data being duplicated not to create as many tables as possible.

Hope this helps
David

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Access tip:

Calculating The Difference Between Dates

If you wish to calculate the time between two date fields, this can be done in a number of ways:

1. As a calculated field in a query
2. As a calculated control in a form or report
3. As a calculation in a VBA procedure.

The basic syntax to get the number of days between two dates is:

=[One Date Field] - [Another Date Field]

You can also use one of the following functions:

=Month([One Date Field] - [Another Date Field])
which calculates the number of months between the two fields

=Year([One Date Field] - [Another Date Field])
which calculates the number of years between the two fields.

Another function is the DateDiff() function.

It uses an argument to determine how the time interval is measured. For example:

=DateDiff("q",[One Date Field] - [Another Date Field])
returns the number of quarters between the two fields.

Other intervals that can be used in this expression are as follows:
"yyyy" - Years
"m" - Months
"d" - Days
"w" - Weekdays
"ww" - Weeks
"h" - Hours
"n" - Minutes
"s" - Seconds