Question

The code below works properly and shows me a list of databases in my database. In the code given below, What is TABLE_CAT and Why is it there ?

import java.sql.*;
public class Database{
public static void main(String [] args) {
Connection con = null;
try {
  con = DriverManager.getConnection("jdbc:mysql://localhost:3306","cowboy","123456");
  DatabaseMetaData meta = con.getMetaData();
  ResultSet res = meta.getCatalogs();
  System.out.println("List of databases: "); 
  while (res.next()) {
     System.out.println("   " + res.getString("TABLE_CAT"));
  }

  res.close();
  con.close();
} catch (SQLException e) {
  System.err.println("SQLException: " + e.getMessage());
}
}
}

Answer 1

TABLE_CAT is the name of the column in your resutSet. As you are iterating over your result set row by row, using res.getString("TABLE_CAT")) allows you to extract the value from that column in the current result row. As meta.getCatalogs() returns catalog names available in a database, the catalog name is then stored under a column called TABLE_CAT.

This should make more sense to you now.