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Saturday, July 9, 2011

Flat File Messages with Positional Records

Positional records within a flat file instance message contain individual fields (items of data) that are each of a predefined length. The fields are parsed according to these lengths.

The character used to fill the unused portion of each field, known as the pad character.

Field Padding: Pad characters are used in fields within both delimited and positional records when the data contained within the field smaller than the number of characters or bytes reserved for the field. These characters occupy the portion of the field not required by the data, if any. Pad characters are specified on a field-by-field basis using the Pad Character and Pad Character Type properties of the corresponding Field Element and Field Attribute nodes. If no pad character is specified for a particular field, the default pad character, space (" "), is used for that field

For inbound instance messages, regardless of whether a particular record is positional or delimited, the flat file disassembler discards leading or trailing instances for the specified or default pad character for a particular field as the instance message is translated into its equivalent XML form. Whether it is leading or trailing instances of the relevant pad character that are discarded depends on whether the Justification property of corresponding Field Element and Field Attribute node is set to Right or Left, respectively.

For outbound instance messages, the flat file assembler will insert the appropriate number of the specified or default pad character into fields so that the length of the field is correct. The pad characters will be inserted before or after the data characters based on whether the Justification property of the corresponding Field Element and Field Attribute node is set to Right or Left, respectively.

When the field to be padded in an outbound instance message is contained within a positional record, the Positional Offset and Positional Length properties of the corresponding Field Element or Field Attribute node, combined with the number of data characters that the field must contain, determine whether any pad characters are required, and if so, how many. When the field to be padded in an outbound instance message is contained within a delimited record, pad characters are only inserted when the value of the Minimum
Length with Pad Character property of the corresponding Field Element or Field Attribute node exceeds the number of data characters.

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