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:

TableSchemaBuilder

Field Summary

Fields

Modifier and Type	Field and Description
private Envelope	envelopeSchema
private TableId	id
private Function<Object[],Object>	keyGenerator
private org.apache.kafka.connect.data.Schema	keySchema
private static org.slf4j.Logger	logger
private Function<Object[],org.apache.kafka.connect.data.Struct>	valueGenerator
private org.apache.kafka.connect.data.Schema	valueSchema

Constructor Summary

Constructors

Constructor and Description

TableSchema(TableId id, org.apache.kafka.connect.data.Schema keySchema, Function<Object[],Object> keyGenerator, Envelope envelopeSchema, org.apache.kafka.connect.data.Schema valueSchema, Function<Object[],org.apache.kafka.connect.data.Struct> 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.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
Envelope	getEnvelopeSchema() Get the Schema that represents the entire value of messages for the table, i.e.
int	hashCode()
TableId	id()
Object	keyFromColumnData(Object[] columnData) Convert the specified row of values into a Kafka Connect key.
org.apache.kafka.connect.data.Schema	keySchema() Get the Schema that represents the table's primary key.
String	toString()
org.apache.kafka.connect.data.Struct	valueFromColumnData(Object[] columnData) Convert the specified row of values into a Kafka Connect value.
org.apache.kafka.connect.data.Schema	valueSchema() Get the Schema that represents the table's columns, excluding those that make up the keySchema().

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

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 Function<Object[],Object> keyGenerator

valueGenerator

private final Function<Object[],org.apache.kafka.connect.data.Struct> valueGenerator

Constructor Detail

TableSchema

public TableSchema(TableId id,
                   org.apache.kafka.connect.data.Schema keySchema,
                   Function<Object[],Object> keyGenerator,
                   Envelope envelopeSchema,
                   org.apache.kafka.connect.data.Schema valueSchema,
                   Function<Object[],org.apache.kafka.connect.data.Struct> 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 Detail

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 Object 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