I am developing an Android app that needs to fetch data from a huge MS Access database of 120MB size.
I have written code to establish connectivity and execute a simple query on the database. I run the same java code on my laptop and my Android device.Here's the code: p
ackage practiceDB;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
import java.util.Scanner;
import net.ucanaccess.converters.TypesMap.AccessType;
import net.ucanaccess.ext.FunctionType;
import net.ucanaccess.jdbc.UcanaccessConnection;
import net.ucanaccess.jdbc.UcanaccessDriver;
public class Example {
private Connection ucaConn;
public Example() {
try {
this.ucaConn = getUcanaccessConnection("VehicleDatabase2.mdb");
} catch (SQLException e) {
e.printStackTrace();
} catch(IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws ClassNotFoundException, SQLException {
System.out.println("Please enter an int");
new Scanner(System.in).nextInt();
try {
Example example = new Example();
example.executeQuery();
} catch (Exception ex) {
System.out.println("An exception : " + ex.getMessage());
}
}
private void executeQuery() throws SQLException {
Statement st = null;
try {
System.out.println("Please enter an int");
new Scanner(System.in).nextInt();
st = this.ucaConn.createStatement();
System.out.println("Please enter an int");
new Scanner(System.in).nextInt();
ResultSet rs = st.executeQuery("Select * from PersonData where EngNo = '1544256'");
System.out.println(" result:");
dump (rs, "executeQuery");
} catch(Exception ex) {
System.out.println("Sarah exception: " + ex.getMessage());
} finally {
if ( st != null ) {
st.close();
}
}
}
private Connection getUcanaccessConnection(String pathNewDB) throws SQLException, IOException {
String url = UcanaccessDriver.URL_PREFIX + "VehicleDatabase2.mdb;newDatabaseVersion=V2003";
return DriverManager.getConnection(url);
}
private void dump(ResultSet rs, String exName)
throws SQLException {
System.out.println("-------------------------------------------------");
System.out.println();
System.out.println();
int jk = 0;
while (rs.next()) {
System.out.print("| ");
int j=rs.getMetaData().getColumnCount();
for (int i = 1; i <=j ; ++i) {
Object o = rs.getObject(i);
System.out.print(o + " | ");
}
System.out.println();
System.out.println();
}
}
}
When it runs on my laptop, the connection takes only about a minute to establish. But when it runs on my Android device, the connection takes more than 10 minutes, and takes up all the heap space, and when the device runs out of memory, the app crashes
What should i do??
Note:
i made some slight changes in this code to run it on android, like adding toasts instead of System.out.println for debugging, i removed the static main function for android, used Environment.getAbsolutePath() to locate the database, etc.
Also, the code that I am running on Android, I first used a 9MB database to check if it works. The code fetches the data as expected from the 9MB database without any issues. The connection takes around 10 seconds to establish in Android in case of the 9MB database (in desktop, it takes less than a second to establish connection with 9MB database)
