Additional validation recommendations
The following conditions are not validated in the FIX type trees. You can extend the validation in your implementation through more mapping or lookups.
| Condition | Explanation |
|---|---|
| Uniqueness of sequence number. | Every message must have a unique sequence number. |
| Reference to fields from previous messages. | Certain conditional rules require field checks from message that is sent or previously processed. |
| ReservedXXXXPlus data types. | Pattern data type used to allow additional bilaterally agreed upon enumerations to be defined starting at XXXX and above. |
| User-defined fields. | Member firms can add their own custom fields, which are published on the FIX website. |
| Bank Identifier Code (BIC), International Securities Identification Numbering System (ISINS) validation, or validations. | Certain fields require a BIC and an International ISINS number or numbers. |
| Encryption. | Certain fields are encrypted, that is, tag #91 Secure Data. |
| Checksum integrity check. | Verifies the check digit value that is specified in the field tag number 10 of the FIX message, against the computed checksum. The computed checksum is the actual sum of the binary value of each character of the message, up to but not including, the checksum field itself. This sum is then transformed into a modulo 256. |
| Fields that have a data type of UTCTimestamp. | Leap Seconds are inserted to account for slowing of the rotation of the earth. During a leap second insertion, a UTCTimestamp field might read "19981231-23:59:59", "19981231-23:59:60", "19990101-00:00:00"." Limitation is on Coordinated Universal Time (UTC) leap seconds set to a value of "60’. |
| Coding schemes | Restricted set of values that are associated with a URI. The URI can be assigned by an external body, or by FpML. |
| XID data types | The constraint added by this data type is that the values of all of the fields that have an ID data type in a FIX message must be unique. |
| XIDREF data types | Defines a reference to an identifier that is defined by the XID data type. |