:MODE=UPDATE

If a duplicate tag is encountered, the DBLoad utility overwrites the existing tag definition in the Tagname Dictionary only with data explicitly specified from the import file. All other data associated with the tag remains unchanged in the Tagname Dictionary.

Fields are considered explicitly defined if the field is in the record and entered by you or is set by the ":KEYWORD=value" mechanism. If a field is not specified in the record, and the keyword has been reset using the ":KEYWORD=" command, the current field value is not updated.

The following is an example of what occurs when an import file in the update mode is loaded/merged into the Tagname Dictionary:

:Mode=update

:Group=Group1

:IODisc,Group,DConversion

Tagname1,Group2,

; Tagname1's Group updated to Group2 only

Tagname2,,

; Tagname2's Group updated to Group1 and the DConversion left as is

Tagname3,,Reverse

; Tagname3's Group updated to Group1 and the DConversion to "Reverse"

; the following line "resets" the Group field to its default value

:Group=

; Data field "Group" is reset to its default value

Tagname4,,

; Tagname4 will be left alone

The tag types must be compatible if the type is being changed and the tag is in use. For example, an existing historical trend tag cannot be changed to an I/O Integer if the tag is in use by the application. Also, a tag cannot be changed to ReadOnly=yes if the tag is being used on an input link in the application. Because of these restrictions, update the use counts for the target application before running the DBLoad utility.