What comments can be added to this code? package attendance; import java.sql.ResultSet; import java.sql.SQLException; import javafx.collections.FXCollections; import javafx.collections.ObservableList; public class RFIDTagsDB { privateSqliteDB db; privatestaticObservableList dbData; publicRFIDTagsDB() throwsClassNotFoundException{ db = new SqliteDB(); dbData = FXCollections.observableArrayList(); } publicObservableListgetDBData(){ return dbData; } publicvoidreadOne(intid) { System.out.println("READ One"); try { this.db.stmt =this.db.conn.createStatement(); System.out.println(db.stmt); String sql ="SELECT * FROM RFIDTags " +"WHERE id = "+ id +""; System.out.println(sql); ResultSet rs =this.db.stmt.executeQuery(sql); while( rs.next() ) { dbData.add( newRFID( rs.getInt("id"), rs.getString("content"), rs.getString("status") ) ); } }catch(Exception e) { System.out.println("Read, Error: "+ e.getMessage()); } } publicvoidread() { System.out.println("READ"); try { this.db.stmt =this.db.conn.createStatement(); System.out.println(db.stmt); String sql ="SELECT * FROM RFIDTags"; System.out.println(sql); ResultSet rs =this.db.stmt.executeQuery(sql); System.out.println(rs); while( rs.next() ) { dbData.add( newRFID( rs.getInt("id"), rs.getString("content"), rs.getString("status") ) ); } }catch(Exception e) { System.out.println("Read, Error: "+ e.getMessage()); } } publicvoidadd(RFIDrfid) throwsSQLException{ try { String sql ="INSERT INTO RFIDTags(content, status) " +"SELECT '"+ rfid.getContent() +"', '"+ rfid.getStatus() +"' " +"WHERE NOT EXISTS(" +"SELECT content " +"FROM RFIDTags " +"WHERE content = '"+ rfid.getContent() +"' " +")"; db.executeQuery(sql); }catch(Exception e) { System.out.println("Add, Error: "+ e.getMessage() ); } } publicvoidmodify(RFIDrfid) { System.out.println(rfid.getId() +" - "+ rfid.getContent() +" - "+ rfid.getStatus() ); try { String sql ="UPDATE RFIDTags " +"SET " +"content = '"+ rfid.getContent() +"', " +"status = '"+ rfid.getStatus() +"' " +"WHERE " +" id = '"+ rfid.getId()+"'"; db.executeQuery(sql); }catch(Exception e) { System.out.println("Modify, Error: "+ e.getMessage()); } } publicvoidremove(RFIDrfid) { try { String sql ="DELETE FROM RFIDTags " +"WHERE id = '"+ rfid.getId() +"'"; db.executeQuery(sql); }catch(Exception e) { System.out.println("Remove, Error: "+ e.getMessage()); } } publicintgetLastInsertedId() throwsSQLException { ResultSet rs = db.stmt.getGeneratedKeys(); if( rs.next() ) { return rs.getInt(1); } return-1; } publicvoidclose() { this.db.closeConnection(); } }

What comments can be added to this code? package attendance; import java.sql.ResultSet; import java.sql.SQLException; import javafx.collections.FXCollections; import javafx.collections.ObservableList; public class RFIDTagsDB { privateSqliteDB db; privatestaticObservableList dbData; publicRFIDTagsDB() throwsClassNotFoundException{ db = new SqliteDB(); dbData = FXCollections.observableArrayList(); } publicObservableListgetDBData(){ return dbData; } publicvoidreadOne(intid) { System.out.println("READ One"); try { this.db.stmt =this.db.conn.createStatement(); System.out.println(db.stmt); String sql ="SELECT * FROM RFIDTags " +"WHERE id = "+ id +""; System.out.println(sql); ResultSet rs =this.db.stmt.executeQuery(sql); while( rs.next() ) { dbData.add( newRFID( rs.getInt("id"), rs.getString("content"), rs.getString("status") ) ); } }catch(Exception e) { System.out.println("Read, Error: "+ e.getMessage()); } } publicvoidread() { System.out.println("READ"); try { this.db.stmt =this.db.conn.createStatement(); System.out.println(db.stmt); String sql ="SELECT * FROM RFIDTags"; System.out.println(sql); ResultSet rs =this.db.stmt.executeQuery(sql); System.out.println(rs); while( rs.next() ) { dbData.add( newRFID( rs.getInt("id"), rs.getString("content"), rs.getString("status") ) ); } }catch(Exception e) { System.out.println("Read, Error: "+ e.getMessage()); } } publicvoidadd(RFIDrfid) throwsSQLException{ try { String sql ="INSERT INTO RFIDTags(content, status) " +"SELECT '"+ rfid.getContent() +"', '"+ rfid.getStatus() +"' " +"WHERE NOT EXISTS(" +"SELECT content " +"FROM RFIDTags " +"WHERE content = '"+ rfid.getContent() +"' " +")"; db.executeQuery(sql); }catch(Exception e) { System.out.println("Add, Error: "+ e.getMessage() ); } } publicvoidmodify(RFIDrfid) { System.out.println(rfid.getId() +" - "+ rfid.getContent() +" - "+ rfid.getStatus() ); try { String sql ="UPDATE RFIDTags " +"SET " +"content = '"+ rfid.getContent() +"', " +"status = '"+ rfid.getStatus() +"' " +"WHERE " +" id = '"+ rfid.getId()+"'"; db.executeQuery(sql); }catch(Exception e) { System.out.println("Modify, Error: "+ e.getMessage()); } } publicvoidremove(RFIDrfid) { try { String sql ="DELETE FROM RFIDTags " +"WHERE id = '"+ rfid.getId() +"'"; db.executeQuery(sql); }catch(Exception e) { System.out.println("Remove, Error: "+ e.getMessage()); } } publicintgetLastInsertedId() throwsSQLException { ResultSet rs = db.stmt.getGeneratedKeys(); if( rs.next() ) { return rs.getInt(1); } return-1; } publicvoidclose() { this.db.closeConnection(); } }

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Related questions

Question

What comments can be added to this code?

package attendance;

	import java.sql.ResultSet;
	import java.sql.SQLException;

	import javafx.collections.FXCollections;
	import javafx.collections.ObservableList;

	public class RFIDTagsDB {
	privateSqliteDB db;
	privatestaticObservableList<RFID> dbData;

	publicRFIDTagsDB() throwsClassNotFoundException{
	db = new SqliteDB();
	dbData = FXCollections.observableArrayList();
	}

	publicObservableList<RFID>getDBData(){
	return dbData;
	}

	publicvoidreadOne(intid) {
	System.out.println("READ One");
	try {
	this.db.stmt =this.db.conn.createStatement();
	System.out.println(db.stmt);

	String sql ="SELECT * FROM RFIDTags "
	+"WHERE id = "+ id +"";

	System.out.println(sql);
	ResultSet rs =this.db.stmt.executeQuery(sql);


	while( rs.next() ) {

	dbData.add(
	newRFID(
	rs.getInt("id"),
	rs.getString("content"),
	rs.getString("status")
	)
	);
	}

	}catch(Exception e) {
	System.out.println("Read, Error: "+ e.getMessage());
	}

	}




	publicvoidread() {
	System.out.println("READ");
	try {
	this.db.stmt =this.db.conn.createStatement();
	System.out.println(db.stmt);

	String sql ="SELECT * FROM RFIDTags";

	System.out.println(sql);
	ResultSet rs =this.db.stmt.executeQuery(sql);

	System.out.println(rs);

	while( rs.next() ) {

	dbData.add(
	newRFID(
	rs.getInt("id"),
	rs.getString("content"),
	rs.getString("status")
	)
	);
	}

	}catch(Exception e) {
	System.out.println("Read, Error: "+ e.getMessage());
	}

	}

	publicvoidadd(RFIDrfid) throwsSQLException{
	try {
	String sql ="INSERT INTO RFIDTags(content, status) "
	+"SELECT '"+ rfid.getContent() +"', '"+ rfid.getStatus() +"' "
	+"WHERE NOT EXISTS("
	+"SELECT content "
	+"FROM RFIDTags "
	+"WHERE content = '"+ rfid.getContent() +"' "
	+")";

	db.executeQuery(sql);

	}catch(Exception e) {
	System.out.println("Add, Error: "+ e.getMessage() );
	}

	}


	publicvoidmodify(RFIDrfid) {
	System.out.println(rfid.getId() +" - "+ rfid.getContent() +" - "+ rfid.getStatus() );
	try {
	String sql ="UPDATE RFIDTags "
	+"SET "
	+"content = '"+ rfid.getContent() +"', "
	+"status = '"+ rfid.getStatus() +"' "
	+"WHERE "
	+" id = '"+ rfid.getId()+"'";

	db.executeQuery(sql);

	}catch(Exception e) {
	System.out.println("Modify, Error: "+ e.getMessage());
	}

	}

	publicvoidremove(RFIDrfid) {
	try {
	String sql ="DELETE FROM RFIDTags "
	+"WHERE id = '"+ rfid.getId() +"'";

	db.executeQuery(sql);

	}catch(Exception e) {
	System.out.println("Remove, Error: "+ e.getMessage());
	}
	}

	publicintgetLastInsertedId() throwsSQLException {
	ResultSet rs = db.stmt.getGeneratedKeys();

	if( rs.next() ) {
	return rs.getInt(1);
	}

	return-1;

	}

	publicvoidclose() {
	this.db.closeConnection();
	}

	}

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