Testing sequential order

You can use the Examine Sequence option to determine if one or more fields in the active table are ordered sequentially, or to identify out-of-sequence items.


Ensure that a quick sort is not currently applied to the active table. The view must display the actual physical order of the underlying ACL table for the Examine Sequence option to provide valid results.

To test sequential order:

  1. Select Analyze > Examine Sequence.
  2. On the Main tab, do one of the following:
    • Select the field(s) to test from the Sequence On list.

    • Click Sequence On to select the field(s), or to create an expression.

    If you select more than one field, the order in which you select the fields dictates the testing priority. The records are tested by the first field you select, and if there are multiple sequential occurrences of the same value in the first field, the records within the group are then tested by the second field you select, and so on. If you do not select additional fields, records within a group are not subject to any secondary testing.


    When testing tables sorted or indexed by more than one field (nested sorting or indexing), testing priority needs to match sorting or indexing priority (primary key field, secondary key field, and so on) for results to be valid.

    The order in which you select the fields is the order in which the columns appear in the results.

  3. If you clicked Sequence On, you can optionally specify a descending sort order for one or more selected fields by clicking the sort arrow (the default is ascending).

    When testing fields that have been previously sorted or indexed, the direction of the sort order you specify – ascending or descending – must match the direction of the field you are testing for results to be valid.

  4. If there are records in the current view that you want to exclude from processing, enter a condition in the If text box, or click If to create an IF statement using the Expression Builder.

    The IF statement considers all records in the view and filters out those that do not meet the specified condition.

  5. Click the Output tab.
  6. Select the appropriate output option in the To panel:
    • Screen – Select this option to display the results in the ACL display area. If the output table contains a large number of records, it is faster and more useful to save the results to a file than to display the results on the screen.

    • Print – Select this option to send the results to the default printer.

    • Graph – Select this option to create a graph of the results and display it in the ACL display area.

    • File – Select this option to save or append the results to a text file. The file is saved outside ACL.


    Output options that do not apply to a particular analytical operation are disabled.

  7. If you selected File as the output type, specify the following information in the As panel:
    • File TypeASCII Text File or Unicode Text file (depending on which edition of ACL you are using) is the only option. Saves the results to a new text file, or appends the results to an existing text file.

    • Name – Enter a file name in the Name text box. Or click Name and enter the file name, or select an existing file in the Save or Save File As dialog box to overwrite or append to the file. If ACL prefills a file name, you can accept the prefilled name, or change it.

      You can also specify an absolute or relative file path, or navigate to a different folder, to save or append the file in a location other than the project location. For example: C:\Results\Output.txt or Results\Output.txt.

    • Local – Disabled and selected. Saving the file locally is the only option.

  8. Depending on the output type, you can optionally specify a Header and/or a Footer in the text box(es).

    Headers and footers are centered by default. Type a left angle bracket (<) before the header or footer text to left align the text. Click Header or Footer to enter a header or footer of more than one line. Alternatively, you can enter a semi-colon (;) as a line-break character in the header or footer text box. Left aligning multiple lines requires a left angle bracket at the beginning of each line.

  9. Click the More tab.
  10. Select the appropriate option in the Scope panel.
    • All – This option is selected by default. Leave it selected to specify that all records in the view will be processed.

    • First – Select this option and enter a number in the text box to start processing at the first record in the view and include only the specified number of records.

    • Next – Select this option and enter a number in the text box to start processing at the currently selected record in the view and include only the specified number of records. The actual record number in the leftmost column must be selected, not data in the row.

    • While – Select this option to use a WHILE statement to limit the processing of records in the view based on a particular criterion or set of criteria. You can enter a condition in the While text box, or click While to create a WHILE statement using the Expression Builder.

      A WHILE statement allows records in the view to be processed only while the specified condition evaluates to true. As soon as the condition evaluates to false, the processing terminates, and no further records are considered. You can use the While option in conjunction with the All, First, or Next options.


    The number of records specified in the First or Next options references either the physical or the indexed order of records in a table, and disregards any filtering or quick sorting applied to the view. However, results of analytical operations respect any filtering.

    If a view is quick sorted, Next behaves like First.

  11. In the Error Limit field, specify the maximum number of non-sequential items to list, or keep the default of 10.

    If the limit is reached, ACL stops processing and outputs the non-sequential items to that point.The Error Limit number applies to the combined number of errors across all fields being tested. It is not a per-field limit.

  12. If you selected File as the output type, and want to append the output results to the end of an existing text file, select Append To Existing File.
  13. Click OK.
  14. If the overwrite prompt appears, select the appropriate option.
Related concepts
About testing sequential order

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