create new document and attachment by ADO.Net

Directly trying to fill all the necessary tables and fields directly/manually is frowned upon. You'll end up fragmenting and/or corrupting your data, essentially causing your site to be useless.

Is there a reason you're choosing to not use the API?

Look at the API examples in your Kentico Installation. Search "API Examples". It will give you the API Calls and it makes it easy. Create Document, Add Attachment, etc.

hi Brenden ,

I thank you for answer.

I choose sql server script because i want get some document and attachment from DB1 and insert to DB2 with a attachment file sharing for 2 databases. but when i use from API, i can not handle this issue

Not sure why you are doing that, but you can use the API and Rest Services API and accomplish the same thing.

To add to what Charles pointed out, if you use a USING statement you can specify the connection string to use for that block of code and then perform your insert using the same dataset or object. Doesn't make any sense at all to risk your data integrity at all to do manual sql CRUD statements when an API is present.

when i use API and this code:

var newAttachment = new AttachmentInfo
                {
                    AttachmentDocumentID = node.DocumentID,
                    AttachmentExtension = item.FileType,
                    AttachmentSize = (int)item.FileSize,
                    AttachmentName = item.FileName,
                    AttachmentMimeType = MimeTypeHelper.GetMimetype(item.FileType),
                    AttachmentTitle = item.FileName,
                    AttachmentDescription = "",
                    AttachmentSiteID = CMS.SiteProvider.SiteContext.CurrentSiteID,
                    AttachmentGUID = guid
                };
                DocumentHelper.AddAttachment(node, "DocFile", guid, groupGuid, newAttachment, provider);
                node.Update();

For each record in the CMS_Attachment table inserted, two different AttachmentGuid inserted. While I have used a single guid for both attachments.

This makes it, both attachments can't take a physical file, because file system use from attachment guid for attachment file name.