Tables and relationships?
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From: Tom van Stiphout on 18 Jan 2010 23:26 On Sun, 17 Jan 2010 18:34:01 -0800, awsmitty <awsmitty(a)discussions.microsoft.com> wrote: Indeed, you can do this and much more once you have an efficient database design. And believe it or not, for the most part all database designers agree on what that structure should be, given a set of requirements. The field names may be different, but you will see very similar structures. This is because relational database design is firmly rooted in the mathematics of set theory and a rookie developer cannot just come around and proclaim that math does not apply to him/her. Once this approach clicks for you, you will see more and more advantages. And you can always come back here and ask more questions. They will be A LOT easier to answer if you have a correct design. -Tom. Microsoft Access MVP <clip> >Now that table may need to be searchable. John makes a donation, files his >taxes, but two years later the IRS comes along and questions it. In the >meantime John has lost his receipt. John, or for that matter the IRS might >come to us to verify that John donated all this stuff. I can find John >easily enough, just give me his address and I�ll use the same routine as when >I found him the first time. I assume what Tom was trying to do, and what I�m >interested in doing just as an educational exersize, is to manage the data >efficiently and conveniently, and learn a little along the way. I assume >Tom�s method would be more efficient. Convenient, well, for you guys that >know this forwards and backward, maybe so, but for me, I have to really keep >my eye on the ball or I�ll loose track of what�s gong on. But, it could >prove to be interesting.
From: Fred on 19 Jan 2010 09:41 I my case it was just agreeing with y'all said, but viewing/explaining such it in a different way. I believe that it more useful to look at a "junction table" as just another table that records entities. In this case, the entity is instances of a an item type being donated. In this case I think that such is not only an entity, but it the main entity that they are recording.
From: Jeff Boyce on 19 Jan 2010 12:10 Tom As an alternative to Single, do you find it useful to use the "Currency" data type? Regards Jeff Boyce Microsoft Access MVP -- Disclaimer: This author may have received products and services mentioned in this post. Mention and/or description of a product or service herein does not constitute endorsement thereof. Any code or pseudocode included in this post is offered "as is", with no guarantee as to suitability. You can thank the FTC of the USA for making this disclaimer possible/necessary. "Tom van Stiphout" <tom7744.no.spam(a)cox.net> wrote in message news:76cal5p355hhai5ubbqokjmlunbi446g9n(a)4ax.com... > On Sun, 17 Jan 2010 13:39:01 -0800, awsmitty > <awsmitty(a)discussions.microsoft.com> wrote: > > I mean that this table will have a field named Quantity, which is of > datatype Single, and it is a required field. > This will allow you to record how many items of a particular kind > there were in one particular donation. I first thought to use Integer > for the data type, but what if someone donated $12.50? Maybe your item > is "money", and your quantity is 12.5. > > -Tom. > Microsoft Access MVP > > > >>Tom. >>At the end of the forth paragraph, you mention"quantity single required". >>I >>have to ask, what do you mean?
From: Tom van Stiphout on 19 Jan 2010 21:31 On Tue, 19 Jan 2010 09:10:35 -0800, "Jeff Boyce" <nonsense(a)nonsense.com> wrote: Usually yes, I am a big proponent of using the smallest and most accurate data type. But I think this is a justifyable exception: we want only a single Quantity field, and it can hold the number of beds donated, or gallons of drinking water, or yards of linnen, etc. -Tom. Microsoft Access MVP >Tom > >As an alternative to Single, do you find it useful to use the "Currency" >data type? > >Regards > >Jeff Boyce >Microsoft Access MVP
From: Jeff Boyce on 20 Jan 2010 11:59
Tom I misunderstood. I thought the "Single" data type was one that offered considerably more precision than "Currency". Regards Jeff "Tom van Stiphout" <tom7744.no.spam(a)cox.net> wrote in message news:sjqcl5h8hpn251n160gr6ikca8fji67e32(a)4ax.com... > On Tue, 19 Jan 2010 09:10:35 -0800, "Jeff Boyce" > <nonsense(a)nonsense.com> wrote: > > Usually yes, I am a big proponent of using the smallest and most > accurate data type. But I think this is a justifyable exception: we > want only a single Quantity field, and it can hold the number of beds > donated, or gallons of drinking water, or yards of linnen, etc. > > -Tom. > Microsoft Access MVP > > >>Tom >> >>As an alternative to Single, do you find it useful to use the "Currency" >>data type? >> >>Regards >> >>Jeff Boyce >>Microsoft Access MVP |