Method: Convert null to constant
Function name: null2constant
Parameter list: (CHAR input, CHAR constant)
Return type: CHAR
What the method does: Converts NULL source columns to the constant value you specify; distributes all other values as is.
The constant is a character string value that may be as many as 254 bytes, and the value is subject to normal Connect CDC truncation or padding rules.
The Connect CDC Director does not prevent you from specifying this method for a source column that has a NOT NULL constraint. Connect CDC Director simply passes non-null values to the target.
You are responsible for ensuring that the type of constant value you specify is suitable for the target column. For example, if the column at the target table is numeric and you specify a character constant, distribution fails.
This method applies only to a source column that has an SQL NULL value, not, for example, to binary zeros in a source column.