Merge pull request #10807 from mladensavic94/master

insert null into Integer column using JDBC

persistence-modules/core-java-persistence-2/src/main/java/com/baeldung/insertnull/DBConfig.java

@@ -0,0 +1,26 @@
+package com.baeldung.insertnull;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+public class DBConfig {
+
+    private static Connection INSTANCE;
+
+    public static Connection getConnection() throws SQLException {
+        if (INSTANCE == null) {
+            INSTANCE = DriverManager.getConnection("jdbc:h2:mem:insertnull", "user", "password");
+            createPersonTable();
+        }
+        return INSTANCE;
+    }
+
+    private static void createPersonTable() throws SQLException {
+        try(Statement statement = INSTANCE.createStatement()) {
+            String sql = "CREATE TABLE Person (id INTEGER not null, name VARCHAR(50), lastName VARCHAR(50), age INTEGER, PRIMARY KEY (id))";
+            statement.executeUpdate(sql);
+        }
+    }
+}

persistence-modules/core-java-persistence-2/src/main/java/com/baeldung/insertnull/Person.java

@@ -0,0 +1,48 @@
+package com.baeldung.insertnull;
+
+public class Person {
+
+    private Integer id;
+    private String name;
+    private String lastName;
+    private Integer age;
+
+    public Person(Integer id, String name, String lastName, Integer age) {
+        this.id = id;
+        this.name = name;
+        this.lastName = lastName;
+        this.age = age;
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+}

persistence-modules/core-java-persistence-2/src/test/java/com/baeldung/insertnull/InsertNullUnitTest.java

@@ -0,0 +1,50 @@
+package com.baeldung.insertnull;
+
+import org.junit.jupiter.api.Test;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Types;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+public class InsertNullUnitTest {
+
+    private final String SQL = "INSERT INTO Person VALUES(?,?,?,?)";
+
+    @Test
+    public void givenNewPerson_whenSetNullIsUsed_thenNewRecordIsCreated() throws SQLException {
+        Person person = new Person(1, "John", "Doe", null);
+
+        try (PreparedStatement preparedStatement = DBConfig.getConnection().prepareStatement(SQL)) {
+            preparedStatement.setInt(1, person.getId());
+            preparedStatement.setString(2, person.getName());
+            preparedStatement.setString(3, person.getLastName());
+            if (person.getAge() == null) {
+                preparedStatement.setNull(4, Types.INTEGER);
+            }
+            else {
+                preparedStatement.setInt(4, person.getAge());
+            }
+            int noOfRows = preparedStatement.executeUpdate();
+
+            assertThat(noOfRows, equalTo(1));
+        }
+    }
+
+    @Test
+    public void givenNewPerson_whenSetObjectIsUsed_thenNewRecordIsCreated() throws SQLException {
+        Person person = new Person(2, "John", "Doe", null);
+
+        try (PreparedStatement preparedStatement = DBConfig.getConnection().prepareStatement(SQL)) {
+            preparedStatement.setInt(1, person.getId());
+            preparedStatement.setString(2, person.getName());
+            preparedStatement.setString(3, person.getLastName());
+            preparedStatement.setObject(4, person.getAge(), Types.INTEGER);
+            int noOfRows = preparedStatement.executeUpdate();
+
+            assertThat(noOfRows, equalTo(1));
+        }
+    }
+}