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# ExchangeRate

ExchangeRate contains data on the rate to be used when converting amounts from one currency into another.

## Schema ID

`https://gobl.org/draft-0/currency/exchange-rate`

## Properties

| Title | Property | Type | Description |
| - | - | - | - |
| From | `from` | [currency.Code](/draft-0/currency/code) | Currency code this will be converted from. |
| To | `to` | [currency.Code](/draft-0/currency/code) | Currency code this exchange rate will convert into. |
| At | `at` | [cal.DateTime](/draft-0/cal/date_time) | At represents the effective date and time at which the exchange rate is determined by the source. The time may be zero if referring to a specific day only. |
| Source | `source` | [cbc.Key](/draft-0/cbc/key) | Source key provides a reference to the source the exchange rate was obtained from. Typically this will be determined by an application used to update exchange rates automatically. |
| Amount | `amount` | [num.Amount](/draft-0/num/amount) | How much is 1 of the "from" currency worth in the "to" currency. |

## Validation Rules

| Field | Test | Validation Code / Message |
| - | - | - |
| `from` | <ul class="gobl-test"><li class="gobl-test-present">Present</li></ul> | `GOBL-CURRENCY-EXCHANGERATE-01`<br />From currency is required |
| `to` | <ul class="gobl-test"><li class="gobl-test-present">Present</li></ul> | `GOBL-CURRENCY-EXCHANGERATE-02`<br />To currency is required |
| `at` | <ul class="gobl-test"><li>Not zero</li></ul> | `GOBL-CURRENCY-EXCHANGERATE-03`<br />Date/time must not be zero |
| `amount` | <ul class="gobl-test"><li>Min 0</li></ul> | `GOBL-CURRENCY-EXCHANGERATE-04`<br />Amount must be positive |


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