Package io.debezium.relational

Class TableSchema

java.lang.Object
io.debezium.relational.TableSchema
All Implemented Interfaces:
DataCollectionSchema
@Immutable public class TableSchema extends Object implements DataCollectionSchema
Defines the Kafka Connect Schema functionality associated with a given table definition, and which can be used to send rows of data that match the table definition to Kafka Connect.

Given a Table definition, creating and using a TableSchema is straightforward: 

 Table table = ...
 TableSchema tableSchema = new TableSchemaBuilder().create(table);
or use a subclass of TableSchemaBuilder for the particular DBMS. Then, for each row of data: 
 Object[] data = ...
 Object key = tableSchema.keyFromColumnData(data);
 Struct value = tableSchema.valueFromColumnData(data);
 Schema keySchema = tableSchema.keySchema();
 Schema valueSchema = tableSchema.valueSchema();
all of which can be handed to Kafka Connect to create a new record.

When the table structure changes, simply obtain a new or updated Table definition (e.g., via an editor), rebuild the TableSchema for that Table, and use the new TableSchema instance for subsequent records.

Author:
Randall Hauch
See Also:

  • Field Details

    • LOGGER

      private static final org.slf4j.Logger LOGGER

    • id

      private final TableId id

    • keySchema

      private final org.apache.kafka.connect.data.Schema keySchema

    • envelopeSchema

      private final Envelope envelopeSchema

    • valueSchema

      private final org.apache.kafka.connect.data.Schema valueSchema

    • keyGenerator

      private final StructGenerator keyGenerator

    • valueGenerator

      private final StructGenerator valueGenerator

  • Constructor Details

    • TableSchema

      public TableSchema(TableId id, org.apache.kafka.connect.data.Schema keySchema, StructGenerator keyGenerator, Envelope envelopeSchema, org.apache.kafka.connect.data.Schema valueSchema, StructGenerator valueGenerator)
      Create an instance with the specified Schemas for the keys and values, and the functions that generate the key and value for a given row of data.
      Parameters:
      id - the id of the table corresponding to this schema
      keySchema - the schema for the primary key; may be null
      keyGenerator - the function that converts a row into a single key object for Kafka Connect; may not be null but may return nulls
      valueSchema - the schema for the values; may be null
      valueGenerator - the function that converts a row into a single value object for Kafka Connect; may not be null but may return nulls

  • Method Details

    • id

      public TableId id()
      Specified by:
      id in interface DataCollectionSchema

    • valueSchema

      public org.apache.kafka.connect.data.Schema valueSchema()
      Get the Schema that represents the table's columns, excluding those that make up the keySchema().
      Returns:
      the Schema describing the columns in the table; never null

    • keySchema

      public org.apache.kafka.connect.data.Schema keySchema()
      Get the Schema that represents the table's primary key.
      Specified by:
      keySchema in interface DataCollectionSchema
      Returns:
      the Schema describing the column's that make up the primary key; null if there is no primary key

    • getEnvelopeSchema

      public Envelope getEnvelopeSchema()
      Get the Schema that represents the entire value of messages for the table, i.e. including before/after state and source info.
      Specified by:
      getEnvelopeSchema in interface DataCollectionSchema
      Returns:
      the table's envelope schema

    • keyFromColumnData

      public org.apache.kafka.connect.data.Struct keyFromColumnData(Object[] columnData)
      Convert the specified row of values into a Kafka Connect key. The row is expected to conform to the structured defined by the table.
      Parameters:
      columnData - the column values for the table
      Returns:
      the key, or null if the columnData

    • valueFromColumnData

      public org.apache.kafka.connect.data.Struct valueFromColumnData(Object[] columnData)
      Convert the specified row of values into a Kafka Connect value. The row is expected to conform to the structured defined by the table.
      Parameters:
      columnData - the column values for the table
      Returns:
      the value, or null if the columnData

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object