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 Introducing PTWin32 |
Most of the more than
70 relational database tables used in the average PTWin32 installation have
fields that are identified as Key fields. A Key value can be
made up of one field or a combination of fields, but once the key fields are
chosen every record in the database table must have a unique value in that Key.
It’s what differentiates between one record and another. Often in PTWin32 the
Key value is an automatically generated number that is invisible to users, but
when warranted, PTWin32 allows users to determine individual Key values. One example of this
is on the Materials tab of the Fee
Tables window that appears when you select Options
| Fee Tables from the Main Menu. Here you can enter individual Material Types and a Rate
which may be used to calculate a Fee. The Material
Types field you see in this table is a Key field. If you Add
2 records to this table that contain the same Material
Type value you will receive an error informing you of a Key
Violation. If you receive a Key
Violation error then all you need to do is re-enter the Material
Type value in a way that does not match other entries in that field. If we
were to allow duplicates in this field then a Calculated Fee that works with these Material Types wouldn’t know which duplicate to use in the
calculation.
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