Options dialog box: Table tab

You can use the options in the Table tab to specify how ACL processes tables.

Automatically Profile on Open

When the Automatically Profile on Open option is turned on, ACL automatically executes the Profile command on all numeric fields when you open a project, change tables, or change global filters.

ACL retains the information and uses it to provide minimum and maximum values for histograms and stratifications, as well as absolute values for monetary unit sampling.

Note

Tables with numeric fields will open more slowly with this option on.

Open View Window

This option automatically opens a view when you select or create a table. If a Default View exists, ACL opens it. Otherwise, ACL opens another available view, or creates a Default View if none is available.

If you turn this option off, you must open a view each time you require one.

Delete Data File with Table

If you turn this option on, ACL automatically deletes the associated data file when you delete a table. You can use this option to quickly remove unwanted files from your hard disk, but it will prevent you from accessing the data in the future.

Note

Use this option with caution. It may be an original data file that is deleted along with the table.

Don’t Share Table Layouts

Generally, you want to maintain a separate table layout for each data file. In some cases, however, you may want to have a single table layout for multiple source data files or data sources with the same record structure. You can deselect the Don’t Share Table Layouts option when you want to allow table layouts to be shared.

Note

To prevent accidental deletion of field definitions, the Don't Share Table Layouts checkbox is selected by default.

When sharing is permitted, source data files (e.g., ACL data files (.fil)) or data sources that have the same record structure can share a single set of field definitions. When you add a field definition to a shared table layout, the added field is available to all of the ACL tables that use the shared table layout. When you delete a field that belongs to a shared table layout, it is no longer available to any of the ACL tables that use the shared table layout.

For example, extracting records from a year’s transaction table into twelve separate tables containing the transactions for each month would produce a total of 13 tables that have the same record structure. If the Don’t Share Table Layouts checkbox is selected (the default setting), each table would have its own layout. If the Don’t Share Table Layouts checkbox is deselected, all 13 tables would share the original table’s layout. Adding or deleting field definitions in any one of the 13 tables would affect all of them in the same way.

The Don’t Share Table Layouts option primarily affects the results of record extractions, sorts, merges, or record samples.

Exact Character Comparisons

When this option is off, ACL compares character fields or expressions that are not of equal length, based on the shortest character field or expression. For example, “AB” is considered to be equal to “ABC” and “ABLMNOP”.

If you turn this option on, ACL compares character fields or expressions based on their full length, which must be exactly the same in order to match. Two strings of different lengths, therefore, are never equal. For example, “AB” is not considered equal to “ABC”.

Changes to this setting are recorded in the log using the following syntax:

SET EXACT {ON|OFF}

Display Format on Open

If you turn this option on, ACL automatically displays the current table layout and computed field definitions when you open a new table. The results appear in the command log.

Changes to this setting are recorded in the log using the following syntax:

SET FORMAT {ON|OFF}

Define Flat Files Manually

With this option selected, certain screens of the Data Definition Wizard are skipped when you create a table from a flat file and you complete the data definition in the Table Layout dialog box.

Buffer Size

This option specifies the size of the data block read. The default is 33K (kilobytes), which is the recommended buffer size for most applications.

Acceptable values range from 5 to 255. Changing the buffer size may provide small performance improvements in certain environments. You should only change this setting if you are advised to do so by ACL Support Services.

Changes to this setting are recorded in the log using the following syntax:

SET READAHEAD value

Sort Memory

This option specifies the maximum amount of system resources to be allocated for sorting and indexing processes. The sort memory can be any value from 0 to 2000MB (megabytes), in 20MB increments. To optimize Sort performance, set the sort memory according to the available physical memory in the system. This enables ACL to use the necessary amount of memory to sort a table up to this maximum, if required.

If the sort memory is left as 0, ACL uses the system resources currently available.

Sort Order

This option sets the sort sequence for character fields.

Choose the locale from the drop-down list. The default is “System Default” for the non-Unicode edition of ACL and “Mix Languages (UCA)” for the Unicode edition. By default, ACL sorts data in ascending order based on the byte order of each character in its character set. The Sort Order option affects sort order when sorting or indexing, or performing a quick sort, and when testing sequential order.

Changes to this setting are recorded in the log using the following syntax:

SET ORDER values

Related tasks
Configuring ACL options


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