Item 

Description 

Name  

Enter the component’s field name.  

Component  

Displays a name you enter in the Name field, prefixed with the component name. The product discards anything you enter directly in the Component edit box.  

Type  

Select the field component’s data type. You must supply a data type for any new field component you create. For example, to display floating point currency values in a field, select Currency from the drop-down list.  

Size  

Specify the maximum number of characters that can be displayed or entered in a string-based field or the size of Bytes and VarBytes fields. For all other data types, Size is meaningless.  

Data  

Replaces an existing field (for example to change its data type) and is based on columns in the table or a query underlying a dataset.  

Calculated  

Displays values calculated at runtime by a dataset’s OnCalcFields event handler.  

Lookup  

Retrieve values from a specified dataset at runtime based on search criteria you specify (not supported for unidirectional datasets).  

InternalCalc  

Retrieves values calculated at runtime by a client dataset and stored with its data (instead of being dynamically calculated in an OnCalcFields event handler). InternalCalc is only available if you are working with a client dataset. Values calculated for an InternalCalc field are stored and retrieved as part of the client dataset’s data.  

Aggregate  

Retrieves a value summarizing the data in a set of records from a client dataset.  

Key Fields  

Lists the fields in the current dataset for which you can match values. To match more than one field, enter field names directly instead of choosing from the drop-down list. Separate multiple field names with semicolons. If you are using more than one field, you must use persistent field components.  

Dataset  

Lists the datasets in which to look up field values. The lookup dataset must be different from the dataset for the field component itself, or a circular reference exception is raised at runtime.  

Lookup Keys  

Used only to create lookup fields. If you choose Lookup as the field type, the Key Fields and Dataset edit boxes in the Lookup definition group box are enabled. The Lookup Keys and Result Field boxes are only enabled if you are connected to a second dataset.  

Result Field  

Lists the fields in the lookup dataset that can be returned as the value of the lookup field you are creating.