Read Exchange Rates
This function enables the system to read the exchange rates that are required for translating an amount from one currency to another, for example.
How the system reads the exchange rate depends on the currency pair, the key date, and the exchange rate category.
If an exchange rate is not available on a key date, the system takes the past age restriction into account when it reads the exchange rate. You define the age to which the system reads back for each exchange rate category in Customizing for Market Data under 
Exchange Rates 
Define Exchange Rate Categories and Translation Ratios 
.
If the system only finds an exchange rate that is too old, it issues a corresponding error message. In this case, the system does not use the exchange rate found.
If you have specified a reference currency for an exchange rate category in Customizing, the system uses this reference currency to determine the exchange rate instead of reading all exchange rates between currencies for this exchange rate category directly from the database table. You can use the exchange rate category to control whether the exchange rates are to be generally read directly from the system or determined by the system on the basis of the reference currency. Note the following points if you want to use a reference currency to determine the exchange rates:
If you have selected a reference currency in Customizing for an exchange rate category, the system uses this reference currency to determine the exchange rates, even if the exchange rate you are searching for is available in the system for the exchange rate category. If the system does not, however, find an exchange rate required for determining the exchange rate on the basis of the reference currency, it attempts to read this exchange rate directly.
If you have defined specific currency pairs but a different exchange rate category (without reference currency) in Customizing, the system does not use the reference currency of the original exchange rate category to determine the exchange rates for these currency pairs. Instead, it reads the exchange rates in accordance with the information in the different exchange rate category.
An exchange rate is to be read for the currency pair JPY/AUD of the exchange rate category With. In Customizing for the exchange rate category, USD is defined as the reference currency.
Exchange Rate Category
Reference Currency
With
USD
The following exchange rates are defined in the system:
Currency Pair
Key Date
Exchange Rate Category
Exchange Rate Factor (From : To)
Rate
JPY/USD
2011–10–01
With
100:1
0.82
AUD/USD
2011–10–01
With
1:1
0.5
JPY/AUD
2011–10–01
With
100:1
1.6
The system uses the reference currency USD to calculate the exchange rate JPY/AUD on October 1, 2011, and for the exchange rate category With. The exchange rates JPY/USD and AUD/USD required for this are defined for the key date.
Currency Pair
Key Date
Exchange Rate Category
Exchange Rate Factor (From : To)
Rate
JPY/AUD
2011–10–01
With
100:1
1.64
The system, therefore, always uses the reference currency to calculate the exchange rates for exchange rate categories that provide a reference currency, even if the exchange rate you are searching for is defined in the system for the exchange rate category.
If, however, even just one of the exchange rates concerned is not available for determining the exchange rates on the basis of the reference currency, the system cannot use the reference currency to determine the exchange rate for a key date. The following data would now be entered:
Currency Pair
Key Date
Exchange Rate Category
Exchange Rate Factor (From : To)
Rate
JPY/USD
2011–10–01
With
100:1
0.82
JPY/AUD
2011–10–01
With
100:1
1.6
On the key date October 1, 2011, the system cannot use the reference currency to determine the exchange rate for the currency pair JPY/AUD, since no exchange rate is available for the currency pair AUD/USD. For this reason, the system attempts to read the exchange rate directly. The following exchange rate is read:
Currency Pair
Key Date
Exchange Rate Category
Exchange Rate Factor (From : To)
Rate
JPY/AUD
2011–10–01
With
100:1
1.6
If you now do not want to use the reference currency to determine the exchange rate for a currency pair (JPY/EUR, for example), define a different exchange rate category in Customizing that does not provide a reference currency for this currency pair. Enter an exchange rate category without a reference currency. The system then reads the exchange rate directly, provided it is available. This enables you to decide for each currency pair whether the reference currency is to be used to determine the exchange rate or whether the system is to read the exchange rate directly. The following data is defined in the system:
Exchange Rate Category
Reference Currency
With
USD
Without
Exchange Rates
Currency Pair
Key Date
Exchange Rate Category
Different Exchange Rate Category
Exchange Rate Factor (From : To)
Rate
JPY/USD
2011–10–01
With
100:1
0.82
EUR/USD
2011–10–01
With
1:1
0.80
JPY/EUR
2011–10–01
With
Without
100:1
JPY/EUR
2011–10–01
Without
100:1
1.00
In this example, the exchange rate is read directly for the currency pair JPY/EUR on the key date October 1, 2011 exchange rate JPY/EUR (exchange rate 1.00) and is not determined on the basis of the reference currency (exchange rate 1.025).
In all these cases, the system must always take into account the age restriction (maximum age), that is, none of the exchange rates involved may be older than the maximum age specified.