Besides the source of the data, which can be configured using properties in the <configuration> element of the configuration file, the import infrastructure uses formatters to interpret the incoming data and convert it for insertion into the database. If you use the CSV or TSV formatter, you can control how the data is interpreted by setting additional properties associated with those formatters. For example, the following configuration for the Kafka importer includes the formatter property blank specifying that blank entries should generate an error, rather than being interpreted as null or empty values:

<import>
  <configuration type="kafka" format="csv" enabled="true">
    <property name="brokers">kafkasvr:9092</property>
    <property name="topics">employees</property>
    <property name="procedure">EMPLOYEE.insert</property>
    <property name="blank">error</property>
  </configuration>
</import>

You include the formatter properties in the <configuration> element along with the import type properties. Table 15.9, “CSV and TSV Formatter Properties” lists the allowable properties for the CSV and TSV import formatters.