VB6 - Store multiple states in a single variable

If you are new to programming you would probably use seperate status fields in a database to define individual statuses. This is not needed if you know a bit about boolean algebra.

The technique I use in the attached project is the same as is used in the windows api. Using this technique will make you write many fewer lines of code to achieve the same result. It also organises your work and allows you to reduce the size of status information stored in a file or in a database.

To better understand this, you should do a search on 'boolean algebra' or 'binary number system'. If I had lots of time I could explain it fully.

If you find this code useful, then please post back with your comments. Send me a pm if you need help.

Here is an interesting addendum:

Imagine a query like:

VB Code:

'The values for each constant added must increase by a multiple
'of two each time eg: 1,2,4,8,16,32,64,128,
Const CLIENT_PAID_IN_FULL = 1
Const CLIENT_DISCOUNT_APPLIES = 2
Const CLIENT_DEFAULTED = 4
 
strSQL = "SELECT * FROM Clients WHERE " & _
        "(client.statusid and " & CLIENT_PAID_IN_FULL & ") = " & CLIENT_PAID_IN_FULL & " AND " & _
        "(client.statusid and " & CLIENT_DISCOUNT_APPLIES & ") = " & CLIENT_DISCOUNT_APPLIES

Instead of defining two (or more fields if otherwise needed), one field handles it all!!!