StreamAccessors >> Can SharePoint 2010 BCS return multiple attachments?

Question

Can SharePoint 2010 BCS return multiple attachments? I have a database which stores multiple attachments per entity. Would like to have all of them accessible, but I've insufficient experience with BCS/BDC to say whether or not this is possible.

Answer 1

If by "multiple attachments per entity" you mean that you have multiple binary columns in SQL table then I suggest you try to create StreamAccessor methods in your BCS Model for each column, see details here:

XML Snippet: Modeling a StreamAccessor Method

You can display links to the binary content in Business Data Web Part with custom XSLT like this:

<a>
  <xsl:variable name="downloadUrl" select="concat($DownloadExternalDataUrl, ddwrt:UrlEncode('BCSStreamAccessorMethodInstanceName'), '&amp;IsXmlEncodedStreamName=true&amp;ItemId=', @*[name()=$ColumnKey])" />
  <xsl:attribute name="href">
    <xsl:value-of select="$downloadUrl" />
  </xsl:attribute>
  <xsl:attribute name="onclick">javascript:DownloadExternalData('BCSStreamAccessorMethodInstanceName', '<xsl:value-of select="@*[name()=$ColumnKey]" />', '<xsl:value-of select="concat($downloadUrl, '&amp;InvisibleFrame=true')" />'); return false;</xsl:attribute>
  <xsl:value-of select="@tpar_binary_fname" />
</a>
<span style="display:none">
  <iframe>
    <xsl:attribute name="name">
      <xsl:value-of select="concat('BCSStreamAccessorMethodInstanceName', @*[name()=$ColumnKey], 'DownloadFrame')" />
    </xsl:attribute>
  </iframe>
</span>