Implementation:Risingwavelabs Risingwave TableSchema

Metadata

Property	Value
File	java/connector-node/connector-api/src/main/java/com/risingwave/connector/api/TableSchema.java
Language	Java
Module	connector-api
Package	com.risingwave.connector.api
Classes	TableSchema
Lines	124

Overview

TableSchema is a core data model class that represents the schema of a table in the RisingWave connector framework. It stores column names, their protobuf data types, column indices, column descriptors, and the list of primary key column names. It provides accessor methods for schema introspection and a static factory method fromProto to construct a TableSchema from a protobuf ConnectorServiceProto.TableSchema message.

This class is used by all sink and source connectors to understand the structure of the tables they interact with.

Code Reference

Source Location

java/connector-node/connector-api/src/main/java/com/risingwave/connector/api/TableSchema.java

Signature

public class TableSchema {
    public TableSchema(List<String> columnNames, List<Data.DataType> dataTypes, List<String> primaryKeys)
    public int getNumColumns()
    public int getColumnIndex(String columnName)
    public TypeName getColumnType(String columnName)
    public ColumnDesc getColumnDesc(int index)
    public Map<String, TypeName> getColumnTypes()
    public String[] getColumnNames()
    public List<ColumnDesc> getColumnDescs()
    public Object getFromRow(String columnName, SinkRow row)
    public static TableSchema fromProto(ConnectorServiceProto.TableSchema tableSchema)
    public List<String> getPrimaryKeys()
    public String toString()
}

Imports

import com.risingwave.connector.api.sink.SinkRow;
import com.risingwave.proto.ConnectorServiceProto;
import com.risingwave.proto.Data;
import com.risingwave.proto.Data.DataType.TypeName;
import com.risingwave.proto.PlanCommon;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

I/O Contract

Constructor

Parameter	Type	Description
columnNames	List<String>	Ordered list of column names in the table
dataTypes	List<Data.DataType>	Ordered list of protobuf data types corresponding to each column
primaryKeys	List<String>	List of column names that form the primary key

The constructor populates the following internal maps:

• columns - Maps column name to TypeName
• columnIndices - Maps column name to its positional index
• columnDescs - List of ColumnDesc objects containing name and full data type info

fromProto (static factory)

Parameter	Type	Description
tableSchema	ConnectorServiceProto.TableSchema	Protobuf table schema message

Direction	Type	Description
Output	TableSchema	A new TableSchema instance built from the protobuf message

Extracts column names and types from the protobuf column descriptors. Primary key indices are resolved to column names using the pkIndices list. Logs the column names after construction.

getFromRow

Parameter	Type	Description
columnName	String	The name of the column to retrieve
row	SinkRow	The row to extract the value from

Direction	Type	Description
Output	Object	The value at the column's index in the row

Usage Examples

// Create a TableSchema from protobuf
TableSchema schema = TableSchema.fromProto(protoTableSchema);

// Inspect the schema
int numCols = schema.getNumColumns();
String[] names = schema.getColumnNames();
TypeName type = schema.getColumnType("user_id");
int idx = schema.getColumnIndex("user_id");

// Get primary keys
List<String> pks = schema.getPrimaryKeys();

// Extract a value from a SinkRow by column name
Object value = schema.getFromRow("user_id", sinkRow);

// Get all column descriptors
List<ColumnDesc> descs = schema.getColumnDescs();

Related Pages

• SinkRow Interface - The row interface used with getFromRow to extract column values
• PkComparator - Uses primary key information from TableSchema for row comparison
• Deserializer Interface - Deserializers produce SinkRows that conform to a TableSchema
• SinkWriterV1 Interface - Sink writers that operate on rows described by TableSchema
• SinkFactory CreateWriter - Factory that uses TableSchema when creating sink writers