The ResultSet interface found in the Java JDBC API is capable of inserting records into a database table. The post demonstrates how to insert rows into a database table using JDBC and Kotlin.

Let’s suppose we the following database table called Menu with the following columns.

Column Name	Type
ID	INT (PK)
ITEM	VARCHAR(255)
PRICE	FLOAT

Our goal is to insert new rows into this table using ResultSet. Here is the Kotlin code that accomplishes the goal followed by an explanation.

fun insertRow(connection: Connection, id: Int, name: String, price: Double) {
    //Obtain an updatable ResultSet object (ResultSet.CONCUR_UPDATABLE)
    val resultSet = connection
            .createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE)
            .executeQuery("SELECT * FROM BURGERS.MENU")

    with(resultSet){
        //Move the ResultSet to the insert row
        moveToInsertRow()
        
        //Populate each column using the relevant update method
        updateInt("ID", id)
        updateString("ITEM", name)
        updateDouble("PRICE", price)
        
        //Now insert the row
        insertRow()
    }
}

The code sample begins by creating a ResultSet object that is able to update the result set. We do this by calling Connection::createStatement() and passing ResultSet.CONCUR_UPDATABLE to the second argument. Once we have a Statement object, we can call executeQuery and passing a SQL query that returns a result set.

Once we have an instance of ResultSet, we can begin adding records to the table. First we need to move the row pointer to insert row by calling ResultSet::moveToInsertRow() (line 9). After we have moved to the insert row, we can populate our database columns using the relevant update methods (lines 12-14). There is one update method for each data type and they are overloaded to use either column indexes or column names.

Once we have finished updating the columns, we can insert the row. We do this by calling ResultSet::insertRow(). The call to insertRow() will attempt to write the record to the datgbase table. The operation will throw a SQLException if the call to insertRow() fails to write the row into the database table.

Example Program

Here is an example Kotlin program that shows how to insert rows into a database table.

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>OCJP-DB</groupId>
    <artifactId>ocjpdb</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <kotlin.version>1.2.0</kotlin.version>
        <main.class>stonesoupprogramming.MainKt</main.class>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derby</artifactId>
            <version>10.14.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-stdlib-jre8</artifactId>
            <version>${kotlin.version}</version>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-test</artifactId>
            <version>${kotlin.version}</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <sourceDirectory>src/main/kotlin</sourceDirectory>
        <plugins>
            <plugin>
                <groupId>org.jetbrains.kotlin</groupId>
                <artifactId>kotlin-maven-plugin</artifactId>
                <version>${kotlin.version}</version>
                <executions>
                    <execution>
                        <id>compile</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>test-compile</id>
                        <phase>test-compile</phase>
                        <goals>
                            <goal>test-compile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <jvmTarget>1.8</jvmTarget>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.6</version>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <mainClass>${main.class}</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.2.1</version>
                <executions>
                    <execution>
                        <phase>test</phase>
                        <goals>
                            <goal>java</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <mainClass>${main.class}</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

BurgerMenu.kt

package stonesoupprogramming

import java.sql.Connection
import java.sql.DriverManager
import java.sql.ResultSet
import java.util.*

private const val SCHEMA = "BURGERS"
private const val TABLE = "MENU"

fun main(args: Array<String>) {
    val properties = Properties()

    //Populate the properties file with user name and password
    with(properties) {
        put("user", "admin")
        put("password", "pw")
    }

    //Open a connection to the database
    DriverManager
            .getConnection("jdbc:derby:stonesoup;create=true", properties)
            .use { connection ->
                    prepareTable(connection)
                    insertItems(connection)
                    queryRows(connection)
                    updatePrice(connection, 6.95)

                    println("\nAfter update")
                    queryRows(connection)
            }
}

fun updatePrice(connection: Connection, price: Double) {
    val sql = "SELECT * FROM $SCHEMA.$TABLE"
    val rs = connection.createStatement(
            ResultSet.TYPE_SCROLL_SENSITIVE,
            ResultSet.CONCUR_UPDATABLE) //This is required to make the ResultSet updatable
            .executeQuery(sql)
    while(rs.next()){
        with(rs) {
            updateDouble("PRICE", price)
            updateRow()
        }
    }
}

private fun queryRows(connection: Connection) {
    val sql = "SELECT * FROM $SCHEMA.$TABLE"
    val rs = connection.createStatement().executeQuery(sql)
    while (rs.next()) {
        println("ID: ${rs.getInt("ID")}\t" +
                "PRICE: $${rs.getDouble("PRICE")}\t" +
                "NAME: ${rs.getString("ITEM")}")
    }
}

private fun insertItems(connection: Connection) {
    insertRow(connection, 1, "'New Bacon-ings'", 5.95)
    insertRow(connection, 2, "'Chorizo Your Own Adventure Burger'", 5.95)
    insertRow(connection, 3, "'Not If I Can Kelp It Burger'", 5.95)
    insertRow(connection, 4, "'The Longest Chard Burger'", 5.95)
    insertRow(connection, 5, "'Peas and Thank You Burger'", 5.95)
    insertRow(connection, 6, "'Cole came, cole slaw, cole conquered burger'", 5.95)
    insertRow(connection, 7, "'Chili Wonka Burger'", 5.95)
    insertRow(connection, 8, "'The Clear and Present Ginger Burger'", 5.95)
}

private fun insertRow(connection: Connection, id: Int, name: String, price: Double) {
    //Obtain an updatable ResultSet object (ResultSet.CONCUR_UPDATABLE)
    val resultSet = connection
            .createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE)
            .executeQuery("SELECT * FROM BURGERS.MENU")

    with(resultSet){
        //Move the ResultSet to the insert row
        moveToInsertRow()

        //Populate each column using the relevant update method
        updateInt("ID", id)
        updateString("ITEM", name)
        updateDouble("PRICE", price)

        //Now insert the row
        insertRow()
    }
}

private fun prepareTable(connection: Connection) {
    val metaData = connection.metaData
    val rs = metaData.getTables(null, SCHEMA, TABLE, null)

    if (!rs.next()) {
        createTable(connection)
    } else {
        truncateTable(connection)
    }
}

private fun truncateTable(connection: Connection) {
    val sql = "TRUNCATE TABLE $SCHEMA.$TABLE"
    with (connection) {
        createStatement().execute(sql)
        commit()
    }
}

private fun createTable(connection: Connection) {
    //SQL statement to create a table
    val sql = """
         CREATE TABLE $SCHEMA.$TABLE (
            ID int primary key,
            ITEM varchar(255),
            PRICE float)
        """.trimMargin()

    with(connection) {
        //Get and instance of statement from the connection and use
        //the execute() method to execute the sql
        createStatement().execute(sql)

        //Commit the change to the database
        commit()
    }
}