ObjectVision 2.1 is more than a Windows development tool. It's also a very powerful front-end to relational databases. This application is an example of what can be accomplished using ObjectVision and several related database tables (we've used both dBASE and Paradox tables).
To help you fully explore ObjectVision's capabilities, we've provided explanation forms in this application which give a technical description of how the application was produced. In addition, we invite you to use the Form, Stack, Link and Tree tools to "open up" the application and see for yourself what's behind it all.
AuctionRAMaV
AuctionRAMaz
AuctionRAMax
Object Oriented Computer Auctionsz
A Brief Introduction{
AuctionRAMa is an auction house that sells classic computer
bytes and PCs and needs to manage the following information:
1. What items are for sale.
2. Who are the Sellers and Bidders.
3. What Bids are placed on each item.
4. Which items are sold
5. The Bids for each Bidder, the winning Bid and how much
each Bidder owes.
6. What proceeds are due to the Seller
7. The commission the Auction House earns.
AuctionRAMa<
AuctionRAMa`
AuctionRAMa^
Object Oriented Computer Auctionsa
That's right! Clicking on the AuctionRAMa logo displays an explanation form.
Throughout
this application,
we've
provided
a unique
way for you to see how we created the forms and links - a look behind the scenes, if you will.
To view an explanation of the current form, simply click on the AuctionRAMa logo
wherever you see it.7
BUBBLE.OVG
AuctionRAMaT
AuctionRAMax
AuctionRAMav
Object Oriented Computer Auctionsy
This is a simple menu form, with push buttons for selection.
AuctionRAMa
AuctionRAMa.
AuctionRAMa,
Object Oriented Computer Auctions1
Sellers & Items-
CSeller Items
Click on the AuctionRAMa logo to look "behind the scenes"
StateY
(###) ###-####
(###) ###-####
This form is used to enter sellers and the items they wish the auction house to sell.
To browse through the records, click in the Seller field or the Description field and select a value from the list.
AuctionRAMa
AuctionRAMa.
AuctionRAMa,
Object Oriented Computer Auctions.
CBidder Bids
Bidders & Bids=
Click on the AuctionRAMa logo to look "behind the scenes"
StateY
(###) ###-####
(###) ###-####
This form is used to view bids on items made by the Bidder shown, or to enter new bids.
To browse through the records, click in the Bidder field or the Description field and select a value from the list.
AuctionRAMa
AuctionRAMa0
AuctionRAMa.
Object Oriented Computer Auctions0
Click on the AuctionRAMa logo to look "behind the scenes"
CSold Items
Items Sold (Seller Report)+
Click in Seller box, then select a Seller from the list.
Table1
Totals:s
This form shows the items sold for any given seller. Click in the seller field to choose a different person.
AuctionRAMa
AuctionRAMa/
AuctionRAMa-
Object Oriented Computer Auctions1
Click on the AuctionRAMa logo to look "behind the scenes"
CItems Purchased
Items Purchased (Bidder Report)*
Click in Bidder field, then select a Bidder from the list.
Table3
Table2y
Totals:y
Purchases:
This form shows which items a particular bidder placed bids on, along with a list of those items they purchased by having the winning bid. The form illustrates a one-to-many-to-many example
AuctionRAMa
AuctionRAMa-
AuctionRAMa+
Object Oriented Computer Auctions.
This is an explanation form. Click on the RETURN button to go back to the real, functional form.
Bidders & Bids>
This form has three associated links. The first to the BIDDER file, the second to the BID file and the third to the ITEMMAX file. All three files are Paradox tables. The Bidder & Bids form is multi-purpose. It allows both adding records to and browsing through the Bidder and/or Bid files.
StateY
State, Phone, and Fax are Picture Fields which allow only entry of characters which match the "picture". Great for phone numbers since you don't have to type brackets and dashes.
(###) ###-####
(###) ###-####
Zip is an "Alphanumeric" type field which retains leading zeros. "General" type fields automatically drop any leading zero.
The "Items" and "List" buttons take you to other forms, from which you may go on to yet other forms. This allows the user to get to any form from any point without going back to a central menu.
Press the Return button to close this form and return to the real, functional form.
AuctionRAMa
AuctionRAMa.
AuctionRAMa,
Object Oriented Computer Auctions0
This is an explanation form. Click on the RETURN button to go back to the real, functional form.
Sellers & Items:
This form incorporates 3 different links. The first writes to the SELLER file. The second to the ITEM file (where the Description, Features and Category field come from), and the third to the ITEMMAX file (which stores the maximum bid on each item).
Both "Seller" and "Description" are Combo Box Type Fields. Click in the field, then select a value from the list OR type in a new value.
StateY
(###) ###-####
(###) ###-####
"Features" is a Scrolling Text Field. Used for long text fields when screen space is scarce. ObjectVision automatically wordwraps and has all the normal text editing features.
"Category" is a Radio Button type field. Used when you have to select ONE option from a short list of choices.
Click RETURN to close this form and return to the real form.T
AuctionRAMa
AuctionRAMa0
AuctionRAMa.
Object Oriented Computer Auctions1
This is an explanation form. Click on the RETURN button to go back to the real, functional form.
Items Sold (Seller Report),
2) The second link - "Item List Max" - is a secondary lookup link. It locates on the Description field and reads in the Sale Amount value from the ITEMMAX Paradox table.
Item Description
Sale Amount
Commission
Net Sale
Table5
Totals:
3) The "Commission" and "Net Sale" values are calculated in the table object through value trees.
1) The first link - "Item List" - uses the restricted range option to locate the many items for the one current Seller. This link is to the ITEM file, a dBase table.
Click on the Return button to go back to the real, functional form.
AuctionRAMa
AuctionRAMa/
AuctionRAMa-
Object Oriented Computer Auctions2
This is an explanation form. Click on the RETURN button to go back to the real, functional form.
Items Purchased (Bidder Report))
This form has two table objects and three links: Two links to the first Table Object (demonstating how a secondary lookup works) and one link with a filter on the second Table Object.
Items Bid On
Amount You Bid
Winning Bid
Table6
The second link - "Bid List Max" - is a secondary lookup link. It returns the Max Bid value by performing a locate on the Description in the ITEMMAX file, which matches the "Items Bid On" field.`
The third link - "Items Bought" - uses a filter to find the records in the ITEMMAX file where the Max Bidder field matches the current bidder.
Items Purchasedv
Purchase Price
Table7w
The first link - "Bid List" - reads the item Descriptions and the Amounts Bid from the BID file. The link utilizes the "auto locate" and "restricted range" features to return all the items bid on by the current bidder.
Totals:w
Purchases:
The number of Items Purchased uses the @Linkcount function, and the Total Purchases field uses the @Linksum function.w
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