The articles in this section of the Knowledge Base involve working with Lists for display in your reports. To learn more about Lists and how to access the Report Designer, see Creating Lists in Report Designer. This article provides information for applying a Filter to a Data band.

Sometimes you may find it necessary to print rows of the Data source that correspond to a definite condition. A Filter is used to select the rows that meet this Condition. To set a Filter, open the Data band editor by double-clicking the Data band. It is also possible to call the Data band editor using the Filter property of the Data band (Figure 01). 

A filter works by establishing a condition to be evaluated as either true or false. Each data row in the Data Source will be processed through the filter individually. If the data row evaluates as true, it will be rendered in the Report. If it evaluates as false, it will be ignored and not be printed. 

1. The Filters tab.
   
2. Add a new Filter. There can be multiple filters per Data band.
   
3. Delete the selected filter.
   
4. Move the selected filter up or down.
   
5. Determines the logical operation type. There are two options for the logical operator—a logical And and a logical Or. When set to And, the data row will output if all filters are true. When set to Or, the data row outputs if at least one of the filters is true.  
   
6. This flag is used to disable/enable filters of the Data band.
   
7. Used to determine the filter engine. For our purposes, Report Engine is adequate. Do not switch to SQL Query unless you have a working knowledge of the SQL language.
   
8. An individual filter set to Expression.
   
9. An individual filter set to Value.
   

There are two ways to set a Filter’s Condition:

1. Value – The Condition is designed using the wizard.
   
2. Expression – The Condition is set as an expression. 
   


Fig. 03 – Value or Expression 

Setting a Condition with the Value Wizard 

1. The way of selecting a condition.
   
2. The type of data that the Condition uses. The five possible data types are Expression, Boolean, DateTime, Numeric, and String. The list of available operations will change depending on the data type.
   
3. The column name from the Data Source. This value is the first value of the Condition.
   
4. This parameter is the operation type. See Figure 05 for a full list of operation types. 
   


Fig. 05 – Operation Types 



5. This parameter is the value in which the data row is compared. Some operations require that two values are specified. The Between operation is one such example. 
   


Fig. 06 – Between Operation 

The Table below features the different Operation types and their descriptions as applied to each data type. 

Setting a Condition using an Expression

The Expression type of Condition is set as a text expression that returns a Boolean value (true or false).

An example of an expression to compare a value to row data is:

Products.Width <= 30

With the Expression above, only Products with a width of 30 or below are displayed in the Report.

Prefilters

Prefilters are a set of filters that can be applied when first opening a report in report designer, prior to loading any of the data bands or tables. This feature can be applied when creating a new report or editing the data source of an existing report by selecting Microvellum Factory or Work Order as the database type, then clicking "Apply Prefilters" in Report Setup.

Fig. 09 - Apply Prefilters in the Report Setup.

Once open, one can select from the various different tables present within the database or work order, filtering out unwanted data from appearing or loading in the first place. With unnecessary data able to be filtered out prior to the report being opened, the report is capable of processing significantly faster, leading to greater degree of speed and ease when working with one's database or within a work order in Report Designer.