Kotlin JDBC – Use ResultSet to Delete Rows

The ResultSet interface found in JDK’s JDBC API may be used to delete rows in a database individually. Here is a Kotlin example that deletes rows from a Burgers.Menu table in the database that match the supplied primary keys.

fun deleteRows(connection: Connection, pks: List<Int>) {
    //Create an updatable Statement (using ResultSet.CONCUR_UPDATABLE)
    val rs = connection
            .createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE)
            .executeQuery("SELECT * FROM BURGERS.MENU WHERE ID IN (${pks.joinToString(", ")})")
    
    while(rs.next()){
        //Delete each row in the ResultSet
        rs.deleteRow()
    }
}

The crux of the operation is found on line 9 with the call to ResultSet::deleteRow(). The method call will simply delete the row from the database. However, it’s important to have the proper ResultSet object prior to calling deleteRow(). On lines 3-5, we create a Statement object (Connection::createStatment) and pass in the ResultSet.CONCUR_UPDATABLE constant to the second paramter of createStaement. If we fail to do so, we will get a SQLException.

It should be noted that while this example shows how to delete records from the database, it should not be a preferred route. The reason is that we are duplicating logic the database already provides. A properly formed SQL statement will perform a bulk delete operation much more efficiently than using ResultSet::deleteRow. ResultSet::deleteRow is much better suited in application where a user is browsing through records and delete items one at a time.

Example Program

Here is a complete Kotlin program that demonstrates the topic discussed in this post.

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)

                    println("\nAfter delete")
                    deleteRows(connection, listOf(1, 3, 5, 7))
                    queryRows(connection)
            }
}

fun deleteRows(connection: Connection, pks: List<Int>) {
    //Create an updatable Statement (using ResultSet.CONCUR_UPDATABLE)
    val rs = connection
            .createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE)
            .executeQuery("SELECT * FROM BURGERS.MENU WHERE ID IN (${pks.joinToString(", ")})")

    while(rs.next()){
        //Delete each row in the ResultSet
        rs.deleteRow()
    }
}

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()
    }
}

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Kotlin JDBC – Insert Row with ResultSet

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()
    }
}

Kotlin JDBC – Update Rows with ResultSet

The ResultSet interface obtained from Statement::executeQuery(String) provides the ability to update individual rows and columns in a database table. Once we have created an updatable ResultSet, we can use the provided update methods to update the row by specifying the column name and the new value. There is an update method for each type of object, so we have updateDouble, updateString, etc.

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

ID PRICE NAME
1 5.95 New Bacon-ings
2 5.95 Chorizo Your Own Adventure Burger

Our goal is to update the PRICE column in all records in the table. Here’s how we would update each PRICE in Kotlin.

val sql = "SELECT * FROM MENU"
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) {
        //Update the value of price
        updateDouble("PRICE", 6.95)
        //Commit the change to the DB
        updateRow()
    }
}

Our first job is the create an updatable ResultSet object. We do this by passing ResultSet.CONCUR_UPDATABLE the second parameter of Connection::createStatement. The first first paramater is also required, but offers flexibility. I chose ResultSet.TYPE_SCROLL_SENSITIVE but there are other ones that are available to the developer.

We will get the following exception if we forget ResultSet.CONCUR_UPDATABLE

Caused by: ERROR XJ083: 'updateDouble' not allowed because the ResultSet is not an updatable ResultSet. 
	at org.apache.derby.iapi.error.StandardException.newException(Unknown Source)
	at org.apache.derby.impl.jdbc.SQLExceptionFactory.wrapArgsForTransportAcrossDRDA(Unknown Source)
	... 12 more

Once we create the proper type of Statement and call it’s executeQuery method, we will have an updatable ResultSet object. The ResultSet object has a variety of update methods that accept both the column name or the column index along with the type of data we are updating. In other words, there is an updateDouble(Int, Double) and an updateDouble(String, Double), updateInt(Int, Int) updateInt(String, Int), etc. We use these methods to update each cell in the database table.

Once we have finished updating a value, we must call the udpateRow() method before moving on to the next row in the result set. If we fail to do so, the changes will not get written to the database. Once updateRow() is called, the changes are persisted to the database and we can move onto the next row in the result set.

Example Program

Below is a complete example program that demonstrates how to update rows in 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) {
    val sql = "INSERT INTO $SCHEMA.$TABLE VALUES ($id, $name, $price)"
    with(connection) {
        createStatement().execute(sql)
        commit()
    }
}

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()
    }
}