Replicating large-object (LOB) datatypes

Replication Server supports the replication of Microsoft SQL Server 2005 datatypes varchar(max), nvarchar(max), and varbinary(max). These datatypes can each store up to 2,147,483,647 bytes of data.

Replication Server introduces LOB datatypes as user-defined datatypes (UDDs) in the table-level replication environment. Replication Server also supports database-level replication for new LOB datatypes. The LOB datatypes are directly mapped to text, unitext, and image datatypes.

The base type of UDDs is:

New LOB datatype

Base type

varchar(max)

text

nvarchar(max)

unitext

varbinary(max)

image

Limitations

The LOB datatypes have these limitations:

In a mixed-version environment, the primary and replicate Replication Server must have a site version of 15.2 and later and an LTL version of 710 and later.

See the Replication Server Heterogeneous Replication Guide for LOB datatype issues with non-ASE data servers. See the Replication Server Reference Manual for more information on LOB datatypes in general.

Partial update of LOB datatypes

Partial-update transaction directly writes a character string at a user-defined position of a table column without issuing a delete and replace command, as would happen in a full update.

Use the rs_updatetext LTL command to implement partial update:

{distribute|_ds} command_tags {applied|_ap} 'table'.rs_updatetext
{partialupd|_pu} [{first|_fi}] [last] [{changed|_ch}] [with log]
[{withouttp|_wo}] [{offset|_os}=offset {deletelen|_dln}=deletelength]
[{textlen|_tl}=length] text_image_column

Partial update does not support multiple character set conversion. Its support is restricted to Microsoft SQL Server 2005.

For more information about partial update, see the Replication Server Design Guide.