SchemaField Class

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This is a Data Abstract Architecture entry
Feel free to add your notes to this topic below.



Overview (.NET)

Represents a field of a DataTable contained in a schema.

Namespace

Declaration (C#)

public class SchemaField : BaseField;

Hierarchy

Properties

Property
Type
Description
Alignment AlignmentType Indicates the alignment the field should use in grids or edit controls.

Note: This property does not have a direct mapping to ADO.NET properties or functionality. It's primarily defined to ensure compatibility with Data Abstract for Delphi, although you can read or set its value and then use it in custom written code.

Calculated Boolean Indicates if the value of the field is calculated on the client or comes from the remote database.
CustomAttributes String This property can be used to store any type of custom information associated with the field.
DefaultValue String The default value for this field when a new record is added to its Data Table.
DictionaryEntry String Specifies the data dictionary entry to use for this field. If assigned (and a TDADataDictionary is assigned to the schema), specific properties of the field will automatically be filled from the data dictionary, rather then being stored with the field itself. This allows to easily share field attributes across an entire application, by defining common field settings in the data dictionary and linking all relevant fields to that dictionary entry.

The following field properties are affected by this. If you are using Schema Modeler to edit your field definition, you will notice that these fields automatically gray out as you assign the DictionaryEntry:

  • Alignment
  • BlobType BusinessClassID
  • DataType DefaultValue DisplayFormat DisplayLabel DisplayWidth
  • EditFormat EditMask
  • GeneratorName
  • ReadOnly RegExpression Required
  • Size
  • Visible
DisplayFormat String A string indicating the format this field should use for client side display.
DisplayLabel String A label indicating the friendly name used to title this field in client applications. This value can be used, for instance, to provide a grid column label or an edit box hint.
DisplayWidth Integer The length of this field when displayed in grid columns.
EditFormat String A mask used client side when editing the value of this field.
EditMask String A mask that restricts the data that can be entered into a field, client side.
InPrimaryKey Boolean Indicates if this field is part of the primary key of this data table.
LogChanges Boolean Indicates if the changes made to this field should be stored in the delta that will be sent to the server when updating the back end database.
ReadOnly Boolean Indicates if this field is read-only.
RegExpression String Stores a regular expression used on to validate the field value, client side.
Required Boolean Indicates if a value for the field is required or the field can be null.
ServerAutoRefresh Boolean Indicates if the value of the field should be re-read after updating a row on the server database.

Note: Some tables might have a trigger associated that updates fields not directly changed by the user. When such situations arise, setting ServerAutoRefresh to true ensures that the record is re-read after the update and the delta going back to the client contains the new value. The new value will finally be merged back in the client data table without requiring another round trip to the server.

Visible Boolean Indicates if this field should be visible in grids or controls, client side.


Methods

Method
Description
AssignToColumn Maps all the properties of this field to the given DataColumn.

Note: Not all properties of a SchemaField have a mapping in ADO.NET. Only the most common properties (i.e. Name, Size) will be assigned to the data column.

SchemaField Default constructor for SchemaField.


See Also


Product: RemObjects Data Abstract
Current version: Data Abstract 'Vinci' (5.0)

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