inserting two tables from multiple databases in jdbc - mysql

Question

How to insert the two tables from two databases in jdbc is it possible?
I have the code but its not working
public class MergeData {
static {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
#SuppressWarnings("unchecked")
public static void main(String[] args) throws SQLException {
//"jdbc:mysql://localhost:3306/fhv1", "root", "root"
DBDataFetcher database1 = new DBDataFetcher("jdbc:mysql://localhost:3306/fhv1", "root", "root");
List<Object> restDetailsList = (List<Object>) database1.fetchTableRows("restdetails");
database1.closeConnection();
long restid = 0;
for(Object obj : restDetailsList) {
if (obj instanceof RestDetails) {
restid = ((RestDetails) obj).getRest_id();
System.out.print(restid + " ");
}
}
DBDataFetcher database2 = new DBDataFetcher("jdbc:mysql://localhost:3306/test", "root", "root");
List<Object> restLocationList = (List<Object>) database2.fetchTableRows("restlocation");
database2.closeConnection();
for(Object obj : restLocationList) {
if (obj instanceof RestLocation) {
((RestLocation) obj).setRest_id(++restid);
System.out.print(((RestLocation) obj).getRest_id() + " ");
restDetailsList.add(obj);
}
}
DBDataMerger merger = new DBDataMerger("jdbc:mysql://localhost:3306/db", "root", "root");
merger.mergeTable(restDetailsList, "restdetails");
merger.closeConnection();
}
}

Answer 1

In plain JDBC, you should create two connections (one for each database)
public Connection getDbConnection(String dbUrl, String driver, String user, String psw){
Connection conn=null;
try{
Class.forName(driver);
conn = DriverManager.getConnection(dbUrl,user,psw);
}catch(SQLException e){
//log exception
}
return conn;
}
And to insert records you can do something like
public void insertRecord(){
//add try and catch/finally
//inserting into 1st DB
Connection conn1 = getDBConnection(dbURl1, driver1, user1, psw1);
Statement stmt = conn1.CreateStatement();
String insert1 = "insert into tbl1 (a,b,c) values(1,2,2);
stmt.executeUpdate(insert1);
//inserting into 2nd DB
Connection conn2 = getDBConnection(dbURl2, driver2, user2, psw2);
stmt = conn2.CreateStatement();//reassing statement or use a new one
String insert2 = "insert into tbl2 (a,b,c) values(1,2,2);
stmt.executeUpdate(insert2);
}
Normally, you'll want to use a PreaparedStatement instead of Statement (because it's usually faster and more secure than a Statement)