ARROW-1780 - JDBC Adapter to convert Relational Data objects to Arrow Data Format Vector Objects

java/adapter/jdbc/pom.xml

@@ -0,0 +1,95 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- 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. -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.apache.arrow</groupId>
+        <artifactId>arrow-java-root</artifactId>
+        <version>0.10.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>arrow-jdbc</artifactId>
+    <name>Arrow JDBC Adapter</name>
+    <url>http://maven.apache.org</url>
+    <dependencies>
+
+        <!-- https://mvnrepository.com/artifact/org.apache.arrow/arrow-memory -->
+        <dependency>
+            <groupId>org.apache.arrow</groupId>
+            <artifactId>arrow-memory</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/org.apache.arrow/arrow-vector -->
+        <dependency>
+            <groupId>org.apache.arrow</groupId>
+            <artifactId>arrow-vector</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>18.0</version>
+        </dependency>
+
+
+        <!-- Test -->
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.11</version>
+            <scope>test</scope>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <version>1.4.196</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.dataformat</groupId>
+            <artifactId>jackson-dataformat-yaml</artifactId>
+            <version>2.7.9</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.7.9</version>
+            <scope>test</scope>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/com.google.collections/google-collections -->
+        <dependency>
+            <groupId>com.google.collections</groupId>
+            <artifactId>google-collections</artifactId>
+            <version>1.0</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <systemPropertyVariables>
+                        <user.timezone>UTC</user.timezone>
+                    </systemPropertyVariables>
+                </configuration>
+
+            </plugin>
+        </plugins>
+    </build>
+</project>

java/adapter/jdbc/src/main/java/org/apache/arrow/adapter/jdbc/JdbcToArrow.java

@@ -0,0 +1,115 @@
+/**
+ * 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.
+ */
+
+package org.apache.arrow.adapter.jdbc;
+
+import org.apache.arrow.memory.RootAllocator;
+import org.apache.arrow.vector.VectorSchemaRoot;
+
+import com.google.common.base.Preconditions;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.ResultSet;
+
+/**
+ * Utility class to convert JDBC objects to columnar Arrow format objects.
+ *
+ * This utility uses following data mapping to map JDBC/SQL datatype to Arrow data types.
+ *
+ * CHAR	--> ArrowType.Utf8
+ * NCHAR	--> ArrowType.Utf8
+ * VARCHAR --> ArrowType.Utf8
+ * NVARCHAR --> ArrowType.Utf8
+ * LONGVARCHAR --> ArrowType.Utf8
+ * LONGNVARCHAR --> ArrowType.Utf8
+ * NUMERIC --> ArrowType.Decimal(precision, scale)
+ * DECIMAL --> ArrowType.Decimal(precision, scale)
+ * BIT --> ArrowType.Bool
+ * TINYINT --> ArrowType.Int(8, signed)
+ * SMALLINT --> ArrowType.Int(16, signed)
+ * INTEGER --> ArrowType.Int(32, signed)
+ * BIGINT --> ArrowType.Int(64, signed)
+ * REAL --> ArrowType.FloatingPoint(FloatingPointPrecision.SINGLE)
+ * FLOAT --> ArrowType.FloatingPoint(FloatingPointPrecision.SINGLE)
+ * DOUBLE --> ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)
+ * BINARY --> ArrowType.Binary
+ * VARBINARY --> ArrowType.Binary
+ * LONGVARBINARY --> ArrowType.Binary
+ * DATE --> ArrowType.Date(DateUnit.MILLISECOND)
+ * TIME --> ArrowType.Time(TimeUnit.MILLISECOND, 32)
+ * TIMESTAMP --> ArrowType.Timestamp(TimeUnit.MILLISECOND, timezone=null)
+ * CLOB --> ArrowType.Utf8
+ * BLOB --> ArrowType.Binary
+ *
+ * @since 0.10.0
+ */
+public class JdbcToArrow {
+
+    /**
+     * For the given SQL query, execute and fetch the data from Relational DB and convert it to Arrow objects.
+     *
+     * @param connection Database connection to be used. This method will not close the passed connection object. Since hte caller has passed
+     *                   the connection object it's the responsibility of the caller to close or return the connection to the pool.
+     * @param query The DB Query to fetch the data.
+     * @return Arrow Data Objects {@link VectorSchemaRoot}
+     * @throws SQLException Propagate any SQL Exceptions to the caller after closing any resources opened such as ResultSet and Statement objects.
+     */
+    public static VectorSchemaRoot sqlToArrow(Connection connection, String query, RootAllocator rootAllocator) throws SQLException {
+        Preconditions.checkNotNull(connection, "JDBC connection object can not be null");
+        Preconditions.checkArgument(query != null && query.length() > 0, "SQL query can not be null or empty");
+
+        try (Statement stmt = connection.createStatement()) {
+            return sqlToArrow(stmt.executeQuery(query), rootAllocator);
+        }
+    }
+
+    /**
+     * For the given JDBC {@link ResultSet}, fetch the data from Relational DB and convert it to Arrow objects.
+     *
+     * @param resultSet
+     * @return Arrow Data Objects {@link VectorSchemaRoot}
+     * @throws Exception
+     */
+    public static VectorSchemaRoot sqlToArrow(ResultSet resultSet) throws SQLException {
+        Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
+
+        RootAllocator rootAllocator = new RootAllocator(Integer.MAX_VALUE);
+        VectorSchemaRoot root = sqlToArrow(resultSet, rootAllocator);
+        rootAllocator.close();
+        return root;
+    }
+
+    /**
+     * For the given JDBC {@link ResultSet}, fetch the data from Relational DB and convert it to Arrow objects.
+     *
+     * @param resultSet
+     * @return Arrow Data Objects {@link VectorSchemaRoot}
+     * @throws Exception
+     */
+    public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, RootAllocator rootAllocator) throws SQLException {
+        Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
+        Preconditions.checkNotNull(rootAllocator, "Root Allocator object can not be null");
+
+        VectorSchemaRoot root = VectorSchemaRoot.create(
+                JdbcToArrowUtils.jdbcToArrowSchema(resultSet.getMetaData()), rootAllocator);
+        JdbcToArrowUtils.jdbcToArrowVectors(resultSet, root);
+        return root;
+    }
+}