Index keys are are normally treated as alphanumeric even if they contain numeric data. Therefore, the results of READ NEXT operations might be unexpected. This directive should be used when the true numeric order is required. In general it will only have an effect for keys defined as signed numeric, but some kinds of unsigned data (for instance COMP-5) may also be affected.
For example, say you have a key defined as pic s9(5), and you had four records for which the key values were 1, -2, 3, -4, stored as:
00001+
00002-
00003+
00004-
If these keys are treated as alphanumeric, they will be retrieved in the above order. However if they are treated as numeric (which is the case when IXNUMKEY is specified), they will be stored (and therefore retrieved when using READ NEXT) in numeric order:
Comments:
Index keys are are normally treated as alphanumeric even if they contain numeric data. Therefore, the results of READ NEXT operations might be unexpected. This directive should be used when the true numeric order is required. In general it will only have an effect for keys defined as signed numeric, but some kinds of unsigned data (for instance COMP-5) may also be affected.
For example, say you have a key defined as pic s9(5), and you had four records for which the key values were 1, -2, 3, -4, stored as:
If these keys are treated as alphanumeric, they will be retrieved in the above order. However if they are treated as numeric (which is the case when IXNUMKEY is specified), they will be stored (and therefore retrieved when using READ NEXT) in numeric order: