Indexing records

Every time you activate the index the condition is automatically reapplied. You can facilitate certain types of analysis by using conditional indexes to create subsets of larger tables.

When a conditional index with an If parameter is active, the words Filtered Index preface the record count in the status bar. For example: Filtered Index Records: 500. When conditional indexes with First, Next, and While parameters are active, the word Indexed prefaces the record count, like indexes without any conditions.

Indexes and filters

When creating a conditional index with an If parameter or a filter, you can include a global filter (a filter on a view), a local filter (a filter within a command), or both.

The table below provides examples of including filters in indexes, and shows the effect that the indexes have on the sample data.

The filters are part of the indexing syntax, which you can view in the log, or in the index details. For more information, see View index details.

1. Select Data > Index.
2. On the Main tab, do one of the following:
   • Select the field(s) to index from the Index On list.
   • Click Index 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 nested indexing priority. The records are indexed by the first field you select, and if there are multiple occurrences of a value in the first field, the records within the group are then indexed by the second field you select, and so on. If you do not select additional fields, records within a group retain their original sort order relative to one another.

   For information about indexing using expressions and computed fields, see Sorting or indexing using a computed key field.

   Note

   The combined length of the fields being indexed cannot exceed 247 characters.

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

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.

   Note

   The If condition is evaluated against only the records remaining in a table after any scope options have been applied (First, Next, While).

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

5. Do one of the following:
   • In the To text box, specify the name of the index file.
   • Click To and specify the index file name, or select an existing index file in the Save or Save File As dialog box to overwrite the file.

   If Analytics prefills an index file name, you can accept the prefilled name, or change it.

   Note

   Index names are limited to 64 alphanumeric characters. The name can include the underscore character ( _ ), but no other special characters, or any spaces. The name cannot start with a number.

   Tip

   A best practice is to give indexes meaningful names that describe the nature of the ordering imposed by the index. For example, “Date_Amount_D” could be the name of an index that orders a table by Date in ascending order, and within each day by Amount in descending order.

6. Select or deselect Use Output Table depending on whether or not you want to activate the index immediately.

   You can activate a table’s index at any time by selecting it from the Index drop-down list at the top right of the view.

7. Click the More tab.
8. 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 are 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. Record processing stops as soon as one limit is reached.

   Note

   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.

9. Click OK.
10. If the overwrite prompt appears, select the appropriate option.

    An entry for the index is added to the Index drop-down list in the View tab. If you selected Use Output Table, the index is activated and the table is sorted according to the index.

• To activate an index, do one of the following:
  • When creating an index, select Use Output Table in the Index dialog box to activate the index right away.
  • Select the index from the Index drop-down list at the top right of the view.
• To deactivate an index, do one of the following:
  • Select (None) in the Index drop-down list at the top right of the view.
  • Switch to another index.
  • Close the table.

1. Open the table containing the index.
2. Right-click the table in the Navigator and select Properties.
3. Click the Indexes tab, select the index name, and click Details.

   The Index Properties dialog box displays the index details:

   • Command displays the syntax of the specific Index command, including any local filter.
   • Filter displays the syntax of any global filter that is part of the index.
4. Click OK and OK again to exit the Table Properties dialog box.

1. Open the table containing the index.
2. Right-click the table in the Navigator and select Properties.
3. Click the Indexes tab, select the index name, and do one of the following:
   • Click Copy to copy the index.

     The index is copied with an incrementing number added to the end of the index name.

   • Click Rename, enter a new name, and click OK to rename the index.

     Note

     Index names are limited to 64 alphanumeric characters. The name can include the underscore character ( _ ), but no other special characters, or any spaces. The name cannot start with a number.

   • Click Delete, then click Delete again to delete the index.
4. If you want to add a new index, click Add.

   The Index dialog box appears, allowing you to create an index in the usual manner.

5. Click OK to exit the Table Properties dialog box.