Select the target columns to include in the data distribution - Connect_CDC - connect_cdc_mimix_share - Latest

The Mapping tab grid displays each target table column and its datatype as well as its default corresponding source column, if any. Copy column under Method in the grid means the source column value is to be distributed without any special handling or transformation.

1. You must select or confirm the individual target columns that are to receive the distributed data, and you must define the source column data and any data transformation results that are distributed. For each such target column:

   1. Select Copy column under Method, and select a source column from the Source Data list, if that target column is to receive source column data not altered by Connect CDC data transformation.

   2. Select or clear the DKey column to indicate whether it is a Distribution Key. For more information about the Distribution Key, see Distribution key requirements.

   3. Select a Method option other than Copy column or NULL(not mapped), and supply Source Data information, if that target column is to receive source data that is the result of Connect CDC transformation. For more information about defining data transformation, see Transform distributed data values.

2. For each target column you want to be excluded from the data distribution, select NULL (not mapped) for Method.

3. For a list of all the source table columns, click the Columns tab of the Properties dialog. Information in these columns cannot be changed.

• A checkmark in the Send column indicates the column is to be distributed from this table. The Send column now is set if the column is used in a simple mapping, a column mapping expression, a gate condition expression, to access a long column by key, or as the source of a join table key. With the exception of a simple mapping, the uses are only detected after a Validate at the server.

• The Name column shows the name of each column in the sending table. Columns whose datatypes are not supported by Connect CDC do not appear in this list.

• The Datatype column shows the SQL datatype of each column in the sending table.

• A checkmark in the PrimeKey column indicates the primary key. A primary key uniquely identifies rows in a table and is enforced by the database management system.

• A checkmark in the ExprUse column indicates that this column is specified in one or more expression definitions for columns on the Mapping page. The Connect CDC Director updates this only at model validation.

• A checkmark in the Receive column indicates rows in this table receiving data from any sending table. This column pertains to data sent to this table. If you are viewing this page from a sending table that is not also a receiving table, this column has no check marks.

• A checkmark in the Nullable column indicates that the column identified can include null values. A column that can contain null values cannot be a Distribution Key for an Oracle or DB2 protected table.