Skip to content

index.md

Latest commit

 

History

History
193 lines (149 loc) · 5.98 KB

index.md

File metadata and controls

193 lines (149 loc) · 5.98 KB
license Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
layout default
title API JDBC
previous
url title
/using_wayang/api_sql/
API SQL

Apache Wayang JDBC Driver

Note: The JDBC driver is under active development and may not yet support all SQL features.

The Wayang JDBC driver allows SQL clients and BI tools to connect to Apache Wayang using the standard JDBC interface. SQL queries are delegated to Wayang's SQL API (api-sql) and executed across Wayang's supported platforms (Java Streams, Apache Spark, etc.).

Getting Started

To use the JDBC driver:

  1. Build Apache Wayang including the wayang-api-jdbc module
  2. Add the generated JDBC JAR to your classpath
  3. Prepare a Wayang configuration file pointing to your data source

Connection

Connect using the following JDBC URL format:

jdbc:wayang:/path/to/wayang-config.properties

Example (Java)

// Driver is auto-registered via Java SPI - Class.forName is optional
Class.forName("org.apache.wayang.api.jdbc.WayangDriver");

Connection conn = DriverManager.getConnection(
    "jdbc:wayang:/path/to/wayang-config.properties"
);

Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM myTable");
while (rs.next()) {
    System.out.println(rs.getString("name") + " " + rs.getInt("value"));
}

rs.close();
stmt.close();
conn.close();

PreparedStatement Example

PreparedStatement ps = conn.prepareStatement(
    "SELECT * FROM myTable WHERE value > ?"
);
ps.setInt(1, 100);
ResultSet rs = ps.executeQuery();

Configuration

The JDBC URL points to a Wayang configuration properties file.

Example wayang-config.properties:

wayang.calcite.model={}
wayang.fs.table.url=file:///path/to/data.csv
wayang.ml.experience.enabled=false
wayang.ml.executions.file=mle.txt
wayang.ml.optimizations.file=mlo.txt

Supported SQL

SQL execution is handled by Wayang's api-sql module. The following SQL operations are generally supported:

Operation Example
SELECT SELECT * FROM customers
Projection SELECT name, age FROM customers
Filter SELECT * FROM customers WHERE age > 30
JOIN SELECT c.name, o.amount FROM customers c JOIN orders o ON c.id = o.customer_id
Aggregation SELECT COUNT(*) FROM customers
GROUP BY SELECT age, COUNT(*) FROM customers GROUP BY age
ORDER BY SELECT * FROM customers ORDER BY age DESC

Metadata Support

The driver implements standard JDBC metadata interfaces used by BI tools and SQL clients:

DatabaseMetaData:

  • getTables() - lists available tables
  • getColumns() - lists column metadata
  • getSchemas() - lists available schemas
  • getDatabaseProductName() - returns "Apache Wayang"
  • getDriverName() - returns "Wayang JDBC Driver"
  • getJDBCMajorVersion() / getJDBCMinorVersion() - returns 4.2

ResultSetMetaData:

  • getColumnCount() - number of columns in result
  • getColumnName(i) - column name by index
  • getColumnType(i) - column SQL type by index

BI Tool Integration

The driver registers automatically via Java SPI (META-INF/services/java.sql.Driver), making it discoverable by JDBC-compatible tools without manual registration.

DBeaver setup:

  1. Go to Database > Driver Manager > New
  2. Set Driver Class: org.apache.wayang.api.jdbc.WayangDriver
  3. Set URL Template: jdbc:wayang:{config_path}
  4. Add the Wayang JDBC JAR to the driver libraries
  5. Connect and browse schemas via the schema browser

How It Works

The driver delegates all SQL execution to Wayang's existing api-sql module:

SQL Client / BI Tool
        |  JDBC
        v
WayangDriver
        |
        v
WayangConnection
        |
        v
WayangStatement / WayangPreparedStatement
        |
        v
SqlContext.executeSql(sql)
        |
        v
Wayang Optimizer (Apache Calcite)
        |
        v
WayangPlan execution
        |
        v
Java Streams / Apache Spark / Apache Flink / ...

The WayangDriver parses the JDBC URL to locate the configuration file, creates a SqlContext, and passes SQL strings directly to SqlContext.executeSql(). Results are returned as a Collection<Record> and wrapped in a WayangResultSet.

Limitations

  • Write operations (INSERT, UPDATE, DELETE) are not supported
  • Transactions are not supported
  • DatabaseMetaData coverage is partial; advanced schema introspection may not be available
  • Complex nested subqueries may not be supported depending on the execution platform
  • Performance depends on the configured Wayang execution platform

Related

  • API SQL - the SQL API that the JDBC driver delegates to
  • WAYANG-55 - JIRA issue tracking this feature