Existence indicators

When the source or destination of a data object exists, the system knows that the entire data object of that source or destination exists. For example, if a source specified to contain a transaction is a file, and that file exists, the transaction exists. On the other hand, if you get a Source not available message, the data object of that source does not exist because the source itself does not exist.

When the data object of a source or destination exists, specific information about errors will appear in the data. For example, you might have any of the following:

• The data object is valid because it conforms to its type definition.
• The type of the data object exists, but has no content.
• The data object is in error because it does not conform to its type definition.
• The data object is valid but contains errors. You indicated that you wanted to ignore certain errors.

In addition to these conditions, the system can also tell if there is any unknown data remaining after the card object has been recognized. This can occur if there really is "junk" at the end. It may also be that enough data was identified to determine the status of the entire object and the data at the end could not, for some reason, be determined to have anything to do with the data object.

When a data object exists, the status of that object is determined by validating its type properties. If an entire data object is an item, it is easy to determine what the status is: whether it is valid or whether it does not match its item format, whether its value is not one of the specified restrictions, or whether it is missing an initiator or terminator. If the source or destination exists and the entire data object is an item, there is nothing else it could possibly be.

If the type of the entire data object is a group, the status of each component must be determined. The system uses existence indicators to determine whether a group component exists. If a component exists, the system can also tell you its status. If a component is required in another component that exists, the system will notify you if that required component is missing.