Using filters

There are several different types of filters you can create in an ACL project. Filters allow you to exclude a portion of the data in a table from displaying, or from being processed by an ACL operation such as extracting. Filters are associated with specific tables rather than the entire project.

Filters are logical expressions that evaluate data in a table and return a value of true (T) or false (F) – for example, Invoice_Amount > 1000.00. Data that evaluates to true is included in the table or the ACL operation, and data that evaluates to false is excluded.

Filters can be applied from a number of different locations in ACL, and they can be used in conjunction with one another. Filters are an essential tool when you are analyzing data.

You can create the following types of filters in ACL:

Filters can be ‘ad hoc’ – that is, not permanently saved with a table – or they can be named and saved with a table for later reuse. Named filters can also be saved in a workspace so they can be shared among multiple tables.

Configurable filter options

Two configurable options allow you to control aspects of filter behavior:

Global filters (view filters)

A global filter applies to the view, or views, associated with a table layout, and restricts which records are displayed, or processed. When a global filter is applied, any operations performed on the table are performed on only the records that the filter includes.

A global filter remains active until you remove it, replace it with another global filter, or close the table. You can make a global filter the default filter for a table so that it is automatically applied every time you open the table.

For more information, see About global filters (view filters).

Quick filters

A quick filter is a global filter that is applied by right-clicking in a view and using the Quick Filter option on the context menu. Quick filters are convenient because they allow you to select filter values and criteria with the mouse, rather than creating them manually, and they automatically populate the Filter text box with valid filter syntax. Because of the need to select filter values and criteria with the mouse, quick filters have certain limitations. They typically cannot be used to create complex filters with multiple criteria.

For more information, see About quick filters.

Local filters (command filters)

A local filter applies to a single execution of a single ACL command, restricting which records in a table the command processes. When the command completes its processing, the local filter is no longer active.

For more information, see About local filters (command filters).

Data filters

Data filters serve a specific purpose. They provide a method for selectively defining data in data sources that contain more than one record type, such as Print Image (Report) files and Multiple Record Type files. Unlike the other types of filters, they are not intended for general use when analyzing data in ACL.

For more information, see About data filters.

Ad hoc and named filters

You can apply a global or local filter using the filter syntax alone – for example, Invoice_Amount > 1000.00 – in which case the filter is ad hoc. Ad hoc filters are not permanently saved with a table. Ad hoc global filters are retained while they appear in the filter history associated with a specific table. Ad hoc local filters are retained for the duration of a single ACL operation – although they can be retrieved from the command log, if necessary.

You can name and save a global or local filter for subsequent reuse, in which case it is permanently saved with the associated ACL table. For example, you could name and save the ad hoc filter Invoice_Amount > 1000.00 as “Inv_greater_1K”. When you reapply the filter, you specify the filter name, rather than recreating the syntax, which saves labor. Naming filters also makes it easy to differentiate between a number of saved filters. You can name and save filters when you create them, or at any subsequent point if the ad hoc filter still appears in the filter history. Once a filter is named and saved, it is available to use as a global filter with any view associated with the table, or as a local filter with any operation performed on the table.

For information about how to name and save a filter, or convert an ad hoc filter to a named filter, see Applying global filters to views.

Filter history

When you apply a global filter to a table it is saved in the filter history associated with the table. As long as the filter remains in the filter history, it can be reapplied by selecting it from the Filter drop-down list at the top of the view. Both ad hoc and named global filters are saved in the filter history. Local filters are not saved in the filter history.

The following details apply to the filter history:

Summary of filter retention

Table 1 provides a summary of filter retention.

Table 1. Summary of filter retention

Permanently saved with table

Added to filter history

Ad hoc global filter

No

Yes

Ad hoc local filter

No

No

Named global filter

Yes

Yes

Named local filter

Yes

No

Related concepts
About global filters (view filters)
About local filters (command filters)
About quick filters
About data filters


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