Map basic messages

When messages are created using a basic or primitive serializer, the message contains a key-value pair. Map the key and value to table columns.

Mapping requirements

When mapping fields to columns, the following requirements apply:

The data in the Pulsar field must be compatible with the mapped column’s data type. For example, a string field cannot map to a number column.
A Pulsar field mapped to a table’s primary key (PK) column must always contain data because primary key columns don’t allow nulls.
All primary key columns must have a mapping because primary key columns don’t allow nulls.

Basic mapping example

In this example, a Pulsar topic named world_topic contains five records with a key-value pair in each. The key is an integer and the value is text.

Create a keyspace in your database.

This example creates a keyspace named world_keyspace:
```
cqlsh -e "CREATE KEYSPACE world_keyspace \
  WITH replication = {'class': 'NetworkTopologyStrategy', \
  'Cassandra': 1};"
```
For DSE and Cassandra clusters, make sure that the keyspace is replicated to a datacenter set in the connector’s contactPoints parameter. DSE datacenter names are case sensitive. Use nodetool ring to get a list of datacenters.

Create a table.

This example creates a table named world_table with two columns:

cqlsh -e "CREATE TABLE world_table (recordid int PRIMARY KEY, continent text);"

For DSE, verify that all nodes have the same schema version using nodetool describering.

For example, this command verifies the schema for world_keyspace:
```
nodetool describering -- world_keyspace
```
In the DataStax connector configuration file, add the Pulsar topic name to topics, and define the field-to-column mapping.

The following example is maps the world_topic to the world_table using the minimum required settings:
```
tasks.max: 1
topics: world_topic
topic:
  world_topic:
    world_keyspace:
      world_table:
        mapping: 'recordid=key, continent=value'
```
Use pulsar-admin sinks update to apply the new configuration.

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