Java: Creating Mysql Database and Table in the same class

Question

I'm creating a java program that creates a MySQL database and table. I'm fairly new, so I'm learning as I go. I was able to create the Database and then I proceed to create the table. When I ran my program I got this exception error

java.sql.SQLException: No database selected

I understand the error that I have, but I don't know I can select the database when I already have my URL setup to my root.

String url = "jdbc:mysql://localhost:3306/";

Below is my code, any feedback is welcome and thank you.

import java.sql.Connection;
import java.sql.Statement;
import java.sql.DriverManager;
import java.sql.SQLException;


public class MysqlSetUp{

private static final String EMPLOYEE_TABLE = "create table MyEmployees3 ( "
  + "   id INT PRIMARY KEY, firstName VARCHAR(20), lastName VARCHAR(20), "
  + "   title VARCHAR(20), salary INT )";

public static Connection getConnection() throws Exception {
String driver = "org.gjt.mm.mysql.Driver";
String url = "jdbc:mysql://localhost:3306/";
String username = "root";
String password = "";
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, username, password);
return conn;
}
  public static void main(String args[]) {
  Connection conn = null;
  Statement stmt = null;
  try {
    conn = getConnection();
    stmt = conn.createStatement();
    stmt.executeUpdate("CREATE DATABASE Employess");
    stmt.executeUpdate(EMPLOYEE_TABLE);
    stmt.executeUpdate("insert into MyEmployees3(id, firstName) values(100, 'A')");
    stmt.executeUpdate("insert into MyEmployees3(id, firstName) values(200, 'B')");
    System.out.println("CreateEmployeeTableMySQL: main(): table created.");
      } catch (ClassNotFoundException e) {
    System.out.println("error: failed to load MySQL driver.");
    e.printStackTrace();
  } catch (SQLException e) {
    System.out.println("error: failed to create a connection object.");
    e.printStackTrace();
  } catch (Exception e) {
    System.out.println("other error:");
    e.printStackTrace();
  } finally {
    try {
      stmt.close();
      conn.close();
    } catch (SQLException e) {
      e.printStackTrace();
     }
   }
  }
 }

@clinomaniac you should add it as an answer, with java code of course. Since it is only what it is needed for his code. — Jorge Campos
– Jorge Campos, Commented Feb 21, 2018 at 21:29

clinomaniac · Accepted Answer · 2018-02-21 21:30:57Z

6

You need to USE Employess after creating it.

...
stmt = conn.createStatement();
stmt.executeUpdate("CREATE DATABASE Employess");
stmt.executeUpdate("USE Employess");
stmt.executeUpdate(EMPLOYEE_TABLE);
...

answered Feb 21, 2018 at 21:30

clinomaniac

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Comments

Jorge Campos · Accepted Answer · 2018-02-21 21:36:02Z

The answer provided by @clinomaniac is right and you should accept it as the right one. This one is to add some more context.

When you create a database as root, in order to work with it you have to select it, so you do it by issuing a USE statement USE yourDatabaseName as already said by @clinomaniac.

Another way to work with your database without using the use command is to prepend every command with your database name like this:

stmt.executeUpdate("insert into Employess.MyEmployees3(id, firstName) values(100, 'A')");
stmt.executeUpdate("insert into Employess.MyEmployees3(id, firstName) values(200, 'B')");

You would have to add this at your create table statement as well:

private static final String EMPLOYEE_TABLE = "create table Employess.MyEmployees3 ( "
   + "   id INT PRIMARY KEY, firstName VARCHAR(20), lastName VARCHAR(20), "
   + "   title VARCHAR(20), salary INT )";

Roshana Pitigala · Accepted Answer · 2018-02-27 12:00:43Z

You can also try adding the database name to the connection url. Modify your getConnection() method like this.

public static Connection getConnection(String dbName) throws Exception {
    String driver = "org.gjt.mm.mysql.Driver";
    String url = "jdbc:mysql://localhost:3306/" + ((dbName != null)? (dbName) : (""));
    String username = "root";
    String password = "";
    Class.forName(driver);
    Connection conn = DriverManager.getConnection(url, username, password);
    return conn;
}

Call getConnection(null) for creating the database, and call getConnection("Employess") after creation of database.

conn = getConnection(null);
stmt = conn.createStatement();
stmt.executeUpdate("CREATE DATABASE Employess");
stmt.close();
conn.close();

conn = getConnection("Employess");
stmt = conn.createStatement();
stmt.executeUpdate(EMPLOYEE_TABLE);
stmt.executeUpdate("insert into MyEmployees3(id, firstName) values(100, 'A')");
stmt.executeUpdate("insert into MyEmployees3(id, firstName) values(200, 'B')");
System.out.println("CreateEmployeeTableMySQL: main(): table created.");

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