Java and SQLite – Importing Data

In order to import data into an SQLite database, it must be in a suitable format. CSV files are one such format. A CSV file, or Comma Separated Values file, is a delimited file that uses commas to separate values. They store tabular data in plain text. The first row in a CSV file often contains headers for each column of data. Each row in the file thereafter is a record of related data. In the example contents of a CSV file below, each row contains information relating to a person, including their first name, last name, title and date of birth in the format YYYY-MM-DD (four digit year, two digit month and two digit day).

"firstname","lastname","title","dob"
"Zoe","Davis","Miss","1979-07-11"
"Tom","Ingram","Mr","1971-10-04"
"Karen","Thomas","Mrs","1969-03-08"
"Samantha","Yates","Miss","1995-08-27"

Below is an example of how Java can be used to import data from a CSV file called ‘personimport.csv’, into a table called ‘person’, which was used in the examples for selecting, inserting, updating and deleting data. For this to work the Apache Commons CSV dependency needs to be used, along with the SQLite JDBC Driver used previously.

Firstly, a check is made to see if the database file actually exists. If it does, a connection to the database is established. A further check is made to see if the CSV file exists. If successfully found, the file is assigned to a reader object and the rows of data, or records, are assigned to a records object. The records are then processed one by one. An SQL ‘Insert‘ statement is constructed, incorporating the values from the record in the records object. This is used to insert the data into the database. Finally, feedback is given as to the number of records added to the database.

import java.io.File;
import java.io.Reader;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVRecord;

public class DemoSQLite {

    public static void main(String[] args) {

        // CSV file path.
        File csvFile = new File("C://Demo//personimport.csv");

        // Database and connection variables.
        File database = new File("C://Demo//testDB.db");
        Connection connect = null;

        // Check if database file exists.
        if (!database.isFile()) {

            // Confirm incorrect database location and stop program execution.
            System.out.println("Error locating database.");
            System.exit(0);

        }

        try {

            // Connect to database.
            connect = DriverManager.getConnection("jdbc:sqlite:" + database.getPath());

        } catch (SQLException e) {

            // Confirm unsuccessful connection and stop program execution.
            System.out.println("Database connection unsuccessful.");
            System.exit(0);

        }

        // Check if CSV file exists.
        if (!csvFile.isFile()) {

            // Confirm incorrect CSV file location and stop program execution.
            System.out.println("Error locating CSV file.");
            System.exit(0);

        } else {

            try {

                // Assign CSV file to reader object and extract the records.
                Reader reader = Files.newBufferedReader(Paths.get(csvFile.getPath()));
                Iterable<CSVRecord> records = 
                        CSVFormat.RFC4180.withFirstRecordAsHeader().parse(reader);

                // Record count.
                int recordCount = 0;

                // Query and statement.
                String sqlPersonInfo;
                PreparedStatement statement = null;

                // Insert person information into the database.
                for (CSVRecord record : records) {

                    // Construct the insert statement.
                    sqlPersonInfo = "INSERT INTO person ";
                    sqlPersonInfo += "(firstname, lastname, title, dob) ";
                    sqlPersonInfo += "VALUES (?, ?, ?, ?) ";

                    // Create statement and bind the parameters.
                    statement = connect.prepareStatement(sqlPersonInfo);
                    statement.setString(1, record.get("firstname"));
                    statement.setString(2, record.get("lastname"));
                    statement.setString(3, record.get("title"));
                    statement.setString(4, record.get("dob"));

                    // Execute query.
                    statement.executeUpdate();

                    // Increment the record count.
                    recordCount += 1;

                }

                // Provide feedback on the number of records added.
                if (recordCount == 0) {

                    System.out.println("No new person records added.");

                } else if (recordCount == 1) {

                    System.out.println(recordCount + " person record added.");

                } else {

                    System.out.println(recordCount + " person records added.");

                }

                // Close the statement and database connection.
                statement.close();
                connect.close();

            } catch (Exception e) {

                // Confirm error adding person information and quit.
                System.out.println("Error adding person information.");
                System.exit(0);

            }

        }

    }

}

The contents of the ‘person’ table now looks as follows.

id firstname lastname title dob
1 Bob Smith Mr 1980-01-20
3 Fred Bloggs Mr 1975-05-07
4 Alan White Mr 1989-03-20
5 Fiona Bloggs Mrs 1985-05-19
6 Zoe Davis Miss 1979-07-11
7 Tom Ingram Mr 1971-10-04
8 Karen Thomas Mrs 1969-03-08
9 Samantha Yates Miss 1995-08-27