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Angel Montes de Oca
Asked: 2020-10-17 10:43:53 +0800 CST 2020-10-17 10:43:53 +0800 CST

How can I check if a certain MySQL database exists from Java?

  • 772

I want to verify if my database exists before continuing with the execution of my program, but I don't know where to start, because I have looked at some examples and nothing has worked for me.

This is the query you want to throw:

"SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = 'Data_base'"
java

3 Answers

  1. Best Answer

    After researching and a few tests I found the solution, create this function to check if it exists, using the jdbc driver:

    public boolean dbExists(String puerto, String db, String pass) {
        boolean exist = false;
        try {
            Connection conn = null;
            Statement st = null;
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:" + puerto + "/" + db, "root", pass);
            st = conn.createStatement();
            String sql = "SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = '" + db + "'";
            ResultSet rs = st.executeQuery(sql);

            if (rs.next()) {
                //JOptionPane.showMessageDialog(main, "La base de datos existe.");
                exist = true;
            }
        } catch (ClassNotFoundException ex) {

        } catch (SQLException ex) {
            //JOptionPane.showMessageDialog(main, "La base de datos no existe.");
            exist = false;
        }
        return exist;
    }

    I hope it will help you in case you are looking for something similar

    • 3

  2. Having previously made a connection to some other base and doing:

    private static void 
  existeBaseDatos(String nom) {

    try {
        PreparedStatement ps;
        ResultSet rs;

        ps = conn.prepareStatement("show databases");
        rs = ps.executeQuery();

        while (rs.next()) {                
            if (rs.getString(1).equals(nom)) {
                System.out.println("Si que existe la BD: "+nom);
                return;
            }
        }
        System.out.println("No existe esa base de datos");
    } catch (SQLException ex) {
        System.out.println("error: " + ex);
    }
}
    • 1

  3. You can use the show databases query with like:

    String sql = "show databases  like '" + db + "'";

    And it checks if the query returns a result.

    • 0