Homogeneous replication
The following section describes how Replicate handles replication from Microsoft SQL Server (MS-CDC) to the following targets: Microsoft SQL Server, Microsoft Azure SQL Database, Microsoft Azure SQL Managed Instance, and Google Cloud SQL for SQL Server.
In homogeneous replication, source column and table collations will be replicated to the target as described in Column and table collation.
- In homogeneous replication, the source data first passes through the Qlik Replicate data type and is therefore subject to any limitations of that type.
- For information on Replicate data types and their limitations (where relevant), see Replicate data types.
- To prevent data truncation when replicating columns with an XML data type, it is strongly recommended to enable the Allow unlimited LOB size option in the task settings.
Data type exceptions
When replicating from Microsoft SQL Server (MS-CDC) to a supported SQL Server-based target, source and target data types are identical, with the following exceptions:
| Microsoft SQL Server (MS-CDC) Source | Microsoft SQL Server-based Target |
|---|---|
|
VARCHAR |
VARCHAR (x) (when x=0 or x>8000) else VARCHAR (max) |
|
NVARCHAR (length) |
NVARCHAR (x) (when x=0 or x>8000) else NVARCHAR (max) |
|
VARBINARY |
VARBINARY (x) (when x=0 or x>8000) else VARBINARY (max) |
|
HIERARCHYID |
VARCHAR (x) |
|
TIMESTAMP |
VARBINARY |
Column and table collation
When replicating from Microsoft SQL Server (MS-CDC) to an SQL Server-based target, column and table collations will be replicated to the target.
To support collation replication, the DBA must ensure that the collations defined for Microsoft SQL Server (MS-CDC) are the same as those defined for the SQL Server-based target.
Non-nullable columns and Primary/Unique Index names
Primary/Unique Index names are preserved during homogeneous replication. Non-nullable columns are also preserved during homogeneous replication, with the exception of the following data types:
- text
- ntext1
- varchar(max)
- nvarchar(max)
- varbinary(max)
- image
- xml