BAEL-7670: Introduction to DuckDB (#16197)
* BAEL-7670: Introduction to DuckDB * BAEL-7670: Introduction to DuckDB
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Manfred
GitHub
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>org.baeldung</groupId>
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<artifactId>duckdb</artifactId>
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<name>duckdb</name>
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<build>
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<plugins>
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<plugin>
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<groupId>org.apache.maven.plugins</groupId>
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<artifactId>maven-compiler-plugin</artifactId>
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<configuration>
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<source>9</source>
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<target>9</target>
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</configuration>
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</plugin>
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</plugins>
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</build>
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<version>0.0.1-SNAPSHOT</version>
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<parent>
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<groupId>com.baeldung</groupId>
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<artifactId>persistence-modules</artifactId>
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<version>1.0.0-SNAPSHOT</version>
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</parent>
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<properties>
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<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
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<duckdb.version>0.10.0</duckdb.version>
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</properties>
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<dependencies>
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<dependency>
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<groupId>org.duckdb</groupId>
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<artifactId>duckdb_jdbc</artifactId>
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<version>${duckdb.version}</version>
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</dependency>
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</dependencies>
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</project>
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package com.baeldung;
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import org.junit.jupiter.api.AfterEach;
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import org.junit.jupiter.api.BeforeAll;
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import org.junit.jupiter.api.BeforeEach;
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import org.junit.jupiter.api.Test;
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import java.io.File;
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import java.io.IOException;
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import java.sql.Connection;
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import java.sql.DriverManager;
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import java.sql.PreparedStatement;
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import java.sql.ResultSet;
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import java.sql.ResultSetMetaData;
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import java.sql.SQLException;
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import java.sql.Statement;
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import java.util.ArrayList;
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import java.util.Calendar;
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import java.util.Date;
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import java.util.List;
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import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
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class DuckDbAccessIntegrationTest {
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private Connection conn = null;
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private Statement stmt = null;
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@BeforeAll
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static void setupOnce() throws Exception {
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Class.forName("org.duckdb.DuckDBDriver");
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}
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@BeforeEach
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void setup() throws SQLException {
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conn = DriverManager.getConnection("jdbc:duckdb:");
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stmt = conn.createStatement();
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}
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@Test
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void whenQueryCurrentDate_thenReturnToday() throws SQLException {
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ResultSet rs = stmt.executeQuery("SELECT current_date");
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Date currentDate = rs.next() ? rs.getDate(1) : null;
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Calendar calendar = Calendar.getInstance();
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calendar.set(Calendar.HOUR_OF_DAY, 0);
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calendar.set(Calendar.MINUTE, 0);
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calendar.set(Calendar.SECOND, 0);
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calendar.set(Calendar.MILLISECOND, 0);
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Date expectedDate = calendar.getTime();
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assertThat(currentDate).isEqualTo(expectedDate);
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}
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@Test
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void whenReadCsv_thenReturnHeaderAndData() throws SQLException {
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String filePath = getResourceAbsolutePath("/customer.csv");
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String query = String.format("SELECT * FROM read_csv('%s')", filePath);
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ResultSet rs = stmt.executeQuery(query);
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ResultSetMetaData metadata = rs.getMetaData();
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List<String> actualHeaderNames = new ArrayList<>();
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for (int n=1; n<=metadata.getColumnCount(); n++) {
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actualHeaderNames.add(metadata.getColumnLabel(n));
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}
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// Then
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List<String> expectedHeaderNames = List.of("CustomerId", "FirstName", "LastName", "Gender");
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assertThat(actualHeaderNames).isEqualTo(expectedHeaderNames);
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int rowCount = 0;
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while (rs.next()) {
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rowCount++;
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}
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assertThat(rowCount).isEqualTo(10);
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}
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@Test
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void whenImportByCsv_thenReturnCorrectRowCount() throws SQLException {
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// When
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String filePath = getResourceAbsolutePath("/customer.csv");
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String query = String.format("CREATE TABLE customer AS SELECT * FROM read_csv('%s')", filePath);
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stmt.executeUpdate(query);
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// Then
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assertThat(getTableRowCount(conn, "customer")).isEqualTo(10);
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}
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@Test
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void whenImportByJson_thenReturnCorrectRowCount() throws SQLException {
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// When
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String filePath = getResourceAbsolutePath("/product.json");
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String query = String.format("CREATE TABLE product AS SELECT * FROM read_json('%s')", filePath);
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stmt.executeUpdate(query);
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// Then
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assertThat(getTableRowCount(conn, "product")).isEqualTo(3);
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}
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@Test
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void whenImportByInsert_thenReturnCorrectRowCount() throws SQLException {
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// When
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stmt.executeUpdate("CREATE TABLE purchase(customerId BIGINT, productId BIGINT)");
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String query = "INSERT INTO purchase(customerId, productId) VALUES (?,?)";
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try (PreparedStatement pStmt = conn.prepareStatement(query)) {
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pStmt.setInt(1, 101);
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pStmt.setInt(2, 1);
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pStmt.addBatch();
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pStmt.setInt(1, 101);
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pStmt.setInt(2, 2);
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pStmt.addBatch();
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pStmt.setInt(1, 102);
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pStmt.setInt(2, 2);
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pStmt.addBatch();
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pStmt.executeBatch();
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}
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// Then
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assertThat(getTableRowCount(conn, "purchase")).isEqualTo(3);
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}
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@Test
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void whenQueryWithJoin_thenReturnCorrectCount() throws SQLException {
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String customerFilePath = getResourceAbsolutePath("/customer.csv");
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String productFilePath = getResourceAbsolutePath("/product.json");
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whenImportByInsert_thenReturnCorrectRowCount();
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String query = String.format("SELECT C.firstName, C.lastName, P.productName " +
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"FROM read_csv('%s') AS C, read_json('%s') AS P, purchase S " +
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"WHERE S.customerId = C.customerId " +
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"AND S.productId = P.productId ",
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customerFilePath, productFilePath);
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int count = 0;
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ResultSet rs = stmt.executeQuery(query);
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while (rs.next()) {
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count++;
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}
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assertThat(count).isEqualTo(3);
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}
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@Test
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void whenExportData_thenFileIsCreated() throws IOException, SQLException {
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createPurchaseView(conn);
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File tempFile = File.createTempFile("temp", "");
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String exportFilePath = tempFile.getAbsolutePath();
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String query = String.format("COPY purchase_view TO '%s'", exportFilePath);
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stmt.executeUpdate(query);
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assertThat(tempFile.length()).isGreaterThan(0);
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tempFile.delete();
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}
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@AfterEach
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void tearDown() throws SQLException {
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stmt.close();
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conn.close();
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}
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private String getResourceAbsolutePath(String name) {
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return this.getClass().getResource(name).getPath().replaceFirst("/", "");
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}
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private int getTableRowCount(Connection conn, String tableName) throws SQLException {
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try (Statement stmt = conn.createStatement()) {
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ResultSet rs = stmt.executeQuery(String.format("SELECT COUNT(*) FROM %s", tableName));
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return (rs.next()) ? rs.getInt(1) : 0;
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}
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}
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private void createPurchaseView(Connection conn) throws SQLException {
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whenImportByCsv_thenReturnCorrectRowCount();
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whenImportByJson_thenReturnCorrectRowCount();
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whenImportByInsert_thenReturnCorrectRowCount();
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String query = "CREATE VIEW purchase_view AS " +
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"SELECT P.productName, COUNT(*) AS purchaseCount " +
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"FROM customer C, product P, purchase S " +
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"WHERE S.customerId = C.customerId " +
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"AND S.productId = P.productId " +
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"GROUP BY P.productName " +
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"ORDER BY COUNT(*) DESC ";
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try (Statement stmt = conn.createStatement()) {
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stmt.executeUpdate(query);
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}
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}
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}
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@ -0,0 +1,11 @@
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CustomerId,FirstName,LastName,Gender
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101,John,Smith,Male
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102,Sarah,Jones,Female
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103,Michael,Johnson,Male
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104,Emily,Davis,Female
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105,David,Brown,Male
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106,Emma,Williams,Female
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107,Alexander,Miller,Male
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108,Samantha,Anderson,Female
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109,Matthew,Taylor,Male
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110,Olivia,Thompson,Female
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[
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{
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"productId": 1,
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"productName":"EZ Curl Bar",
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"category": "Sports Equipment"
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},
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{
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"productId": 2,
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"productName": "7' Barbell",
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"category": "Sports Equipment"
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},
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{
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"productId": 3,
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"productName": "Single Mouthguard - Black",
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"category": "Sports Equipment"
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}
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]
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@ -24,6 +24,7 @@
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<module>core-java-persistence-2</module>
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<module>core-java-persistence-3</module>
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<module>couchbase</module>
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<module>duckdb</module>
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<module>elasticsearch</module>
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<module>flyway</module>
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<module>flyway-repair</module>
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