WriteField Method

In This Topic

Description

Writes a dataset into a database field

Syntax

Visual Basic
Public Sub WriteField( _ ByVal Field As Object, _ ByVal isPart10 As Boolean, _ Optional ByVal TransferSyntax As Variant, _ Optional ByVal Quality As Variant _ )

Visual Basic

Public Sub WriteField( _
   ByVal Field As Object, _
   ByVal isPart10 As Boolean, _
   Optional ByVal TransferSyntax As Variant, _
   Optional ByVal Quality As Variant _
)

Parameters

Field

The field into which the image or dataset is to be Written.
This must be from the list of supported interfaces below, and must be of a type capable of holding binary objects. In Microsoft Access, this would be either an OLE or Memo field. The supported object types are:

Object Category	Version	Object Type
ActiveX Data Objects ADO	>=1.5	Field
Data Access Objects DAO	3.0 or 3.5	Field
Remote Data Objects RDO	2.0	Column

isPart10

If TRUE, a blank 128 byte header, DICM marker, and meta-header are written at the start of the field.
If FALSE, the field is written in the unofficial, but common format, with no header, and using the little-endian implicit VR transfer syntax.

TransferSyntax

Specifies the full UID of the transfer syntax used when Part 10 format is specified. If omitted, the little-endian explicit VR transfer syntax is used.

Quality

The quality factor to be used.

Remarks

The field would normally be read by the ReadField method, but may be copied from the field to an external file.
Quality is specific to the compression method being used, and is ignored for non-compressed or lossless JPEG transfer syntaxes. For Lossy JPEG, it is an integer in the range 1-100, the higher the number, the better the quality (and the larger the file) , and for JPEG 2000 lossy, it is a compression ratio. Other compression methods may use this for other purposes in the future.

This method has been provided to allow development of a DICOM servers using Microsoft tools such as Access and SQL server, which have limited facilities for the handling of Binary Large Objects (BLOBs).
Note:
Whilst this method is useful for simple demonstrations and small projects, most database servers do not handle large BLOBs well when stored within the main database, and in a “production” environment, storage in simple files is strongly advised (with storage of just the filename within the database).