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Example: Discounts

This example shows how you can implement a discount using the calculation framework. You can also implement discounts using WebSphere Commerce Accelerator.


Example description

Your store wants to offer a discount on the Books product category for a limited time. The time period is from StartDate to EndDate. The discount offers customers a 15.00 discount on their orders when the value before taxes of products from the Books category is 50.00 or greater.

The currency of the order is the local currency of the country or region where the store is located.

The discount does not affect any tax calculations. Taxes are calculated using order totals before the discount. This example does not cover the implementation of these tax calculations.

All store customers are eligible for this discount.


Discounts example implementation

To use the calculation framework to calculate shipping charges for this example...

  1. Define a calculation code.

  2. Define a calculation rule.

  3. Define a calculation scale.

  4. Define the calculation ranges.

  5. Define the look-up results for the calculation ranges.

  6. Associate the calculation scales with the calculation rules.

  7. Attach the calculation code with the Books product category catalog entry.

Important: Text identifiers are used in the following sections to make it easier to see the relationships between components.

Text identifiers are often not valid in the WebSphere Commerce database. You should convert the text identifiers to integers or allow WebSphere Commerce to generate the identifiers for you.


Define discount calculation codes

One calculation code needs to be defined in this example because the discount in this example is independent of other discounts that the store might be offering. Also, the discount only applies to one product category. The CalculationCodeQualify calculation method that must be specified as part of a calculation code does not need to be invoked in this example, so the restriction flag is not set.

Here are the key properties required for the calculation code define:

Property Value Description of value
Group method 0 The calculation code will be attached to only one catalog group (Books). Grouping products is useful when the calculation code will be attached to multiple parent products.
Qualification flag 0 The CalculationCodeQualify calculation method specified for this calculation code will not be invoked
Identify string Book Discount Promotion This is a character string that uniquely identifies this calculation code, given a particular calculation usage and store or store group.
Published 1 The calculation code is active
Start date StartDate This calculation code starts being active on StartDate
End date EndDate This calculation code stops being active on EndDate
Calculation usage ID -1 This is the ID for discount calculation usage
CalculationCodeQualify calculation method -2 This is the ID for CalculationCodeQualifyCmd
CalculationCodeApply calculation method -4 This is the ID for DiscountCalculationCodeApplyCmd
CalculationCodeCalculate calculation method -3 This is the ID for CalculationCodeCalculateCmd


Define discount calculation rules

You need one calculation rule to calculate this discount.

Here are the key properties for the calculation rule define:

Property Value Description of value
Calculation code ID BookDiscCode This is the discount calculation code that was defined earlier
Identify number 1 This is a number that, along with the calculation code ID, uniquely identifies this calculation rule.
Qualification flag 0 The CalculationRuleQualify calculation method that you specify for this calculation rule will not be invoked.
Combination 2 The results of this calculation rule can be combined with other calculation rules that have a 0 or 2 combination property. In this example, the value of the combination property has no effect because only one calculation rule is being defined for this calculation code
CalculationRuleQualify calculation method -6 Calculation method ID for DiscountCalculationRuleQualifyCmd
CalculationRuleCalculate calculation method -7 Calculation method ID for CalculationRuleCalculateCmd


Define discount calculation scales

The discount for this example can be expressed as one calculation scale, as this table shows:

Value of Book OrderItems Fixed amount discount
less than 50.00 0.00
50.00 or greater 15.00

This table provides hints about how calculation scales and calculation ranges will be implemented:

The calculation scale should be associated with a currency since the look-up number is a monetary amount. The currency will not be indicated in this example, but it is required when implementing this example in WebSphere Commerce.

You should define one scale for each currency that the store supports. In this example, the store supports only one currency, so we will define only one scale.

The following tables indicate the key values for the calculation scales:

Property Value Description of value
Calculation usage -1 Discount calculation usage
Identify string Book Discount Promotion This is a character string that uniquely identifies this calculation scale, given a particular calculation usage and store or store group.
CalculationScaleLookup calculation method -10 NonDiscountedPriceCalculationScaleLookupCmd (the look-up number is the sum of the non-discounted prices of the Book OrderItems)


Define discount calculation ranges

The discount has two calculation ranges for the calculation scale. The calculation ranges are:

The calculation ranges are not cumulative.

Here are the key properties that define for each calculation range:

Table 1. Book0to50Range calculation range properties
Property Value Description of value
Calculation scale ID BookDiscountScale Calculation scale defined earlier
Calculation range starting value 0.00 Calculation range applies when the sum of non-discounted prices of the OrderItems is greater than or equal to 0.00
Cumulative calculation range indicator 0 Calculation range is non-cumulative.
CalculationRange calculation method -13 FixedAmountCalculationRangeCmd (the look-up result is treated as a fixed monetary amount)

Property Value Description of value
Calculation scale ID BookDiscountScale Calculation scale defined earlier
Calculation range starting value 50.00 Calculation range applies when the sum of non-discounted prices of the OrderItems is greater than or equal to 50.00
Cumulative calculation range indicator 0 Calculation range is non-cumulative
CalculationRange calculation method -13 FixedAmountCalculationRangeCmd (the look-up result is treated as a fixed monetary amount)


Define look-up results for discount calculation ranges

Each calculation range needs a set of look-up results. For this example, the look-up results are fixed monetary amounts. Each calculation range has only one value associated with it, so only one look-up result is needed for each range. Each look-up result must be associated with the local currency of the country or region for the store because that is the currency of the shipping charges.

The look-up result values are added to price and other existing monetary amounts that are associated with an order item. For a discount, the look-up result value is a negative number.

The following tables show the key properties that define for each calculation range look-up result. The currency has been omitted here, but it must be included in an actual implementation.

Property Value Description of value
Look-up result 0.00 No discount
Calculation range ID Book0to50Range The identifier of the calculation range to which this look-up result belongs

Property Value Description of value
Look-up result -15.00 15.00 discount
Calculation range ID Book50+Range The identifier of the calculation range to which this look-up result belongs

Reminder:

These calculation range look-up result properties are missing the currency for the look-up results. The currency of the look-up results must be defined. For this example, it must match the currency of the calculation scale.


Associating discount calculation scales with discount calculation rules

The calculation scale that was defined must be associated with the defined calculation rule in the CRULESCALE database table. The relationship between the defined calculation scale and the defined calculation rule is shown in the following table:

Calculation scales Calculation rules
BookDiscountScale BookDiscRule


Attach discount calculation code

To use the new discount calculation code that you defined earlier, attach the calculation code to the order items. The calculation code will be indirectly attached, because it applies to all items resulting from a customer purchasing a product from the store catalog, not to just one item.

The discount calculation code applies only to Books, so we will attach it to the catalog group for that product category. We will indirectly attach the calculation code by creating an entry in the CATGPCALCD database table.

Populate the CATGPCALCD database table with the following information:

Store ID Catalog group ID Calculation code
Store BookCategory BookDiscCalcCode


Related concepts

Calculation framework

Calculation methods

Calculation rules

Calculation scales and calculation ranges

Calculation usages

Calculation codes

Related reference

Example: Shipping charges

Example: Sales tax and shipping tax calculations


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