BAEL-7670: Introduction to DuckDB (#16197)

* BAEL-7670: Introduction to DuckDB

* BAEL-7670: Introduction to DuckDB

persistence-modules/duckdb/pom.xml

@@ -0,0 +1,42 @@
+<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>
+
+    <groupId>org.baeldung</groupId>
+    <artifactId>duckdb</artifactId>
+    <name>duckdb</name>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>9</source>
+                    <target>9</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+    <version>0.0.1-SNAPSHOT</version>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>persistence-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <duckdb.version>0.10.0</duckdb.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.duckdb</groupId>
+            <artifactId>duckdb_jdbc</artifactId>
+            <version>${duckdb.version}</version>
+        </dependency>
+    </dependencies>
+
+</project>

persistence-modules/duckdb/src/test/java/com/baeldung/DuckDbAccess.java

@@ -0,0 +1,198 @@
+package com.baeldung;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+
+class DuckDbAccessIntegrationTest {
+
+    private Connection conn = null;
+    private Statement stmt = null;
+
+    @BeforeAll
+    static void setupOnce() throws Exception {
+        Class.forName("org.duckdb.DuckDBDriver");
+    }
+
+    @BeforeEach
+    void setup() throws SQLException {
+        conn = DriverManager.getConnection("jdbc:duckdb:");
+        stmt = conn.createStatement();
+    }
+
+    @Test
+    void whenQueryCurrentDate_thenReturnToday() throws SQLException {
+        ResultSet rs = stmt.executeQuery("SELECT current_date");
+        Date currentDate = rs.next() ? rs.getDate(1) : null;
+
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(Calendar.HOUR_OF_DAY, 0);
+        calendar.set(Calendar.MINUTE, 0);
+        calendar.set(Calendar.SECOND, 0);
+        calendar.set(Calendar.MILLISECOND, 0);
+        Date expectedDate = calendar.getTime();
+
+        assertThat(currentDate).isEqualTo(expectedDate);
+    }
+
+    @Test
+    void whenReadCsv_thenReturnHeaderAndData() throws SQLException {
+        String filePath = getResourceAbsolutePath("/customer.csv");
+        String query = String.format("SELECT * FROM read_csv('%s')", filePath);
+
+        ResultSet rs = stmt.executeQuery(query);
+        ResultSetMetaData metadata = rs.getMetaData();
+
+        List<String> actualHeaderNames = new ArrayList<>();
+        for (int n=1; n<=metadata.getColumnCount(); n++) {
+            actualHeaderNames.add(metadata.getColumnLabel(n));
+        }
+
+        // Then
+        List<String> expectedHeaderNames = List.of("CustomerId", "FirstName", "LastName", "Gender");
+        assertThat(actualHeaderNames).isEqualTo(expectedHeaderNames);
+
+        int rowCount = 0;
+        while (rs.next()) {
+            rowCount++;
+        }
+        assertThat(rowCount).isEqualTo(10);
+    }
+
+    @Test
+    void whenImportByCsv_thenReturnCorrectRowCount() throws SQLException {
+        // When
+        String filePath = getResourceAbsolutePath("/customer.csv");
+        String query = String.format("CREATE TABLE customer AS SELECT * FROM read_csv('%s')", filePath);
+        stmt.executeUpdate(query);
+
+        // Then
+        assertThat(getTableRowCount(conn, "customer")).isEqualTo(10);
+    }
+
+    @Test
+    void whenImportByJson_thenReturnCorrectRowCount() throws SQLException {
+        // When
+        String filePath = getResourceAbsolutePath("/product.json");
+        String query = String.format("CREATE TABLE product AS SELECT * FROM read_json('%s')", filePath);
+        stmt.executeUpdate(query);
+
+        // Then
+        assertThat(getTableRowCount(conn, "product")).isEqualTo(3);
+    }
+
+    @Test
+    void whenImportByInsert_thenReturnCorrectRowCount() throws SQLException {
+        // When
+        stmt.executeUpdate("CREATE TABLE purchase(customerId BIGINT, productId BIGINT)");
+
+        String query = "INSERT INTO purchase(customerId, productId) VALUES (?,?)";
+        try (PreparedStatement pStmt = conn.prepareStatement(query)) {
+
+            pStmt.setInt(1, 101);
+            pStmt.setInt(2, 1);
+            pStmt.addBatch();
+
+            pStmt.setInt(1, 101);
+            pStmt.setInt(2, 2);
+            pStmt.addBatch();
+
+            pStmt.setInt(1, 102);
+            pStmt.setInt(2, 2);
+            pStmt.addBatch();
+
+            pStmt.executeBatch();
+        }
+
+        // Then
+        assertThat(getTableRowCount(conn, "purchase")).isEqualTo(3);
+    }
+
+    @Test
+    void whenQueryWithJoin_thenReturnCorrectCount() throws SQLException {
+        String customerFilePath = getResourceAbsolutePath("/customer.csv");
+        String productFilePath = getResourceAbsolutePath("/product.json");
+        whenImportByInsert_thenReturnCorrectRowCount();
+
+        String query = String.format("SELECT C.firstName, C.lastName, P.productName " +
+                "FROM read_csv('%s') AS C, read_json('%s') AS P, purchase S " +
+                "WHERE S.customerId = C.customerId " +
+                "AND S.productId = P.productId ",
+                customerFilePath, productFilePath);
+
+        int count = 0;
+        ResultSet rs = stmt.executeQuery(query);
+        while (rs.next()) {
+            count++;
+        }
+
+        assertThat(count).isEqualTo(3);
+    }
+
+    @Test
+    void whenExportData_thenFileIsCreated() throws IOException, SQLException {
+        createPurchaseView(conn);
+
+        File tempFile = File.createTempFile("temp", "");
+        String exportFilePath = tempFile.getAbsolutePath();
+        String query = String.format("COPY purchase_view TO '%s'", exportFilePath);
+        stmt.executeUpdate(query);
+
+        assertThat(tempFile.length()).isGreaterThan(0);
+        tempFile.delete();
+    }
+
+    @AfterEach
+    void tearDown() throws SQLException {
+        stmt.close();
+        conn.close();
+    }
+
+    private String getResourceAbsolutePath(String name) {
+        return this.getClass().getResource(name).getPath().replaceFirst("/", "");
+    }
+
+    private int getTableRowCount(Connection conn, String tableName) throws SQLException {
+        try (Statement stmt = conn.createStatement()) {
+            ResultSet rs = stmt.executeQuery(String.format("SELECT COUNT(*) FROM %s", tableName));
+            return (rs.next()) ? rs.getInt(1) : 0;
+        }
+    }
+
+    private void createPurchaseView(Connection conn) throws SQLException {
+        whenImportByCsv_thenReturnCorrectRowCount();
+        whenImportByJson_thenReturnCorrectRowCount();
+        whenImportByInsert_thenReturnCorrectRowCount();
+
+        String query = "CREATE VIEW purchase_view AS " +
+                "SELECT P.productName, COUNT(*) AS purchaseCount " +
+                "FROM customer C, product P, purchase S " +
+                "WHERE S.customerId = C.customerId " +
+                "AND S.productId = P.productId " +
+                "GROUP BY P.productName " +
+                "ORDER BY COUNT(*) DESC ";
+
+        try (Statement stmt = conn.createStatement()) {
+            stmt.executeUpdate(query);
+        }
+    }
+
+}

persistence-modules/duckdb/src/test/resources/customer.csv

@@ -0,0 +1,11 @@
+CustomerId,FirstName,LastName,Gender
+101,John,Smith,Male
+102,Sarah,Jones,Female
+103,Michael,Johnson,Male
+104,Emily,Davis,Female
+105,David,Brown,Male
+106,Emma,Williams,Female
+107,Alexander,Miller,Male
+108,Samantha,Anderson,Female
+109,Matthew,Taylor,Male
+110,Olivia,Thompson,Female

persistence-modules/duckdb/src/test/resources/product.json

@@ -0,0 +1,17 @@
+[
+  {
+    "productId": 1,
+    "productName":"EZ Curl Bar",
+    "category": "Sports Equipment"
+  },
+  {
+    "productId": 2,
+    "productName": "7' Barbell",
+    "category": "Sports Equipment"
+  },
+  {
+    "productId": 3,
+    "productName": "Single Mouthguard - Black",
+    "category": "Sports Equipment"
+  }
+]

persistence-modules/pom.xml

@@ -24,6 +24,7 @@
         <module>core-java-persistence-2</module>
         <module>core-java-persistence-3</module>
         <module>couchbase</module>
+        <module>duckdb</module>
         <module>elasticsearch</module>
         <module>flyway</module>
         <module>flyway-repair</module>