Develop Reference

java.sql.SQLSyntaxErrorException: Select Statement won't work [duplicate]

This question already has an answer here:
Syntax error due to using a reserved word as a table or column name in MySQL
(1 answer)
Closed 3 years ago.
My select statement shows the error
java.sql.SQLSyntaxErrorException: You have an error in your SQL
syntax; check the manual that corresponds to your MySQL server version
for the right syntax to use near 'condition from food' at line 1.
My parameter values are object = "food" and columns[] = {"foodName, foodPrice, condition"}
This function still works for my login though
I already use different versions of mySQL and also put brackets around the statement and it still doesn't work
public static String[][] checkDatabase(String object, String[] columns){
Connection myCon = null;
Statement myStm = null;
ResultSet myRs = null;
try {
myCon = DriverManager.getConnection("jdbc:mysql://localhost:3306/softwaredesignorder", "root","SeanLink_11");
myStm = myCon.createStatement();
String temp = "select ";
for (int i = 0; i < columns.length; i++) {
if (i < columns.length - 1) {
temp = temp + columns[i] + ", ";
} else {
temp = temp + columns[i];
}
}
temp = temp + " from " + object;
//PreparedStatement pStm = myCon.prepareStatement(temp);
//pStm.execute();
myRs = myStm.executeQuery(temp);
myRs.last();
String[][] returner = new String[myRs.getRow()][columns.length];
myRs.beforeFirst();
int row = 0;
while (myRs.next()){
int length = columns.length, col = 0;
while (length != 0) {
try {
returner[row][col] = myRs.getString(columns[col]);
} catch (IllegalArgumentException e1) {
try {
returner[row][col] = Integer.toString(myRs.getInt(columns[col]));
} catch (IllegalArgumentException e2) {
try {
returner[row][col] = Double.toString(myRs.getDouble(columns[col]));
} catch (IllegalArgumentException e3) {
try {
Date date = myRs.getDate(columns[col]);
DateFormat dateFormat = new SimpleDateFormat("yyyy-mm-dd");
returner[row][col] = dateFormat.format(date);
} catch (IllegalArgumentException e4) {
System.err.println("Could not retrieve data");
} catch (Exception e) {
System.err.println(e);
}
}
}
}
col += 1;
length -= 1;
}
row += 1;
}
return returner;
} catch (SQLException exSQL) {
System.err.println(exSQL);
}
return null;
};
I want the output to have the data from the entire table but only the selected column.

I believe your problem is that condition is a reserved work in most SQL languages as detailed in https://dev.mysql.com/doc/refman/5.5/en/keywords.html#keywords-5-5-detailed-C, that is why your code works on some cases, is because you don't always have a column named condition you need to escape it using backticks.

Have you try to output back the query you made? i think this one have issue on your query builder. Just simply System.out.println(temp) and check the query syntax before you query on MySQL.

"conditional" is a reserved word in MySQL. You could avoid this error by surrounding your select list items with quotes:
for (int i = 0; i < columns.length; i++) {
String column = "\"" + colunms[i] + "\"";
if (i < columns.length - 1) {
temp = temp + column + ", ";
} else {
temp = temp + column;
}
}

Not able to run executeUpdate()

I have been trying to insert data into DB using prepared statement but not able to run stmt.executeUpdate() The query will insert the field from the array which is declared below,The statement will set the values from the array.
long[] array = new long[100];
int[] devreg = new int[10];
int count = 0, index = 0;
try
{
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(Constants.DB_URL, Constants.USER, Constants.PASS);
// LogMgr.dblogger.info(name +" : Database connection established"); //connection passed
}
catch (Exception e)
{
LogMgr.dblogger.info("Cannot connect to database" + e.toString()); //connection failure
}
if (conn != null) //if connection passed or available
{ //checking device registration
String InsertQuery = " INSERT INTO `acc_dev_db`.`widhb` (`name`,`age`, `type`) VALUES ";
int needacomma = 0;
for (int i=0; i< noofMsg; i++)
{
long empid = array[(i*indexlength)+1];
try
{
Statement s = conn.createStatement ();
s.executeQuery ("SELECT `empid` FROM `acc_dev_db`.`ID` WHERE `widevid` = "+empid+";");
ResultSet rs = s.getResultSet ();
if (rs.next())
{
devstatus = true;
if(needacomma>0)
{
InsertQuery = InsertQuery + ",";
}
InsertQuery = InsertQuery + "(?,?,?,?)";
needacomma += 1;
devreg[j] = i;
j++;
LogMgr.dblogger.info("ID found registered : " + empid); //found device id in the device table. Known device
}
else
{
LogMgr.dblogger.info("ID found not registered : " + empid);
}
rs.close ();
s.close ();
}
catch (Exception e) {
LogMgr.dblogger.info("Database reading error \n" + e.toString() ); //database reading error
}
}
if (devstatus == true) //if device is registered or known device
{
InsertQuery = InsertQuery + ";";
java.sql.PreparedStatement stmt = conn.prepareStatement(InsertQuery);
int loc = 1;
for (count = 0;count < j; count++)
{
int position = (indexlength*devreg[count]);
stmt.setLong(loc, array[position]);
System.out.println( array[position]);
stmt.setDouble(loc + 1, array[position + 1]);
System.out.println( array[position+1]);
stmt.setTimestamp(loc + 2,dateconvert(2, array[position + 2]));
System.out.println( array[position+2]);
stmt.setLong(loc + 3, array[position + 3]);
System.out.println( array[position+3]);
loc += 4;
}
LogMgr.jmslogger.info(stmt.toString());
try{
stmt.executeUpdate();
LogMgr.dblogger.info(name +" : studentdata update successfull from dev : " + devaddress);
}
catch(SQLException e){
System.out.println("EXCEPTION MAN!!!");
}
conn.close ();
}
Current O/P:
12355419
3740073994
491504582
43690
EXCEPTION MAN!!!

You Should throw SqlException or use try-catch block and for manage SqlException

How to show a arraylist of string on jlabel?

Hi I have an arraylist of strings, I want to show the content of the arraylist on JLabel separated by a space or comma. But it shows me only one String, the last one.
public void ShowMovie(int idMovie) throws SQLException, IOException {
int ID = idMovie;
String IDMOVIE = Integer.toString(ID);
IDMovieLabel.setText(IDMOVIE);
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException ex) {
Logger.getLogger(Cover.class.getName()).log(Level.SEVERE, null, ex);
}
con = DriverManager.getConnection("jdbc:mysql://localhost/whichmovie", "Asis", "dekrayat24");
String sql = "SELECT Title,Year,Country,recomendacion,Cover,Rating,NameDirec,Name FROM movie "
+ "Inner join direction on (movie.idMovie=direction.idMovie5)"
+ "Inner join director on (direction.idDirector=director.idDirector)"
+ "Inner join cast on (movie.idMovie=cast.idMovie4)"
+ "Inner join actor on (cast.idActor=actor.idActor)"
+ "where idMovie= '" + ID + "'";
st = con.prepareStatement(sql);
rs = st.executeQuery(sql);
while (rs.next()) {
String titulo = rs.getString(1);
int añoInt = rs.getInt(2);
String año = Integer.toString(añoInt);
byte[] imagedataCover = rs.getBytes("Country");
byte[] imagedataCover1 = rs.getBytes("Cover");
format = new ImageIcon(imagedataCover);
format2 = new ImageIcon(imagedataCover1);
TituloLabel.setText(titulo);
AñoLabel.setText(año);
CountryLabel.setIcon(format);
DirectorLabel.setText(rs.getString(7));
int Recomend = rs.getInt(4);
String Recom = Integer.toString(Recomend);
RecommendLabel.setText(Recom);
int Rating = rs.getInt(6);
String Rat = Integer.toString(Rating);
RatingLabel.setText(Rat);
starRater1.setSelection(Rating);
starRater1.setEnabled(false);
Image imgEscalada = format2.getImage().getScaledInstance(CoverLabel.getWidth(),
CoverLabel.getHeight(), Image.SCALE_SMOOTH);
Icon iconoEscalado = new ImageIcon(imgEscalada);
CoverLabel.setIcon(iconoEscalado);
ArrayList<String> actors = new ArrayList<>();
actors.add(rs.getString(8));
System.out.println(actors);// Here i can see i get 9 actors.
StringBuilder sb = new StringBuilder();
boolean first = true;
for (String s : actors) {
if (!first) {
sb.append(' ');
}
sb.append(s);
first = false;
}
CastLabel1.setText(sb.toString());
}
rs.close();
st.close();
con.close();
}
Any help ?
Edit:unfortunately no solution has helped me, maybe I'm doing something wrong in the method, I post the full method.

String text = "";
for(int i = 0; i < actors.size(); i++){
text = text + actors.get(i);
if(i < actors.size() - 2){
text = text + ", ";
}
}
CastLabel1.setText(text);

The problem is you are resetting the label for each step in the for loop, and not creating a cumulative result. See below:
StringBuilder buf = new StringBuilder();
for(int i = 0; i < actors.size(); i++){
buf.append(actors.get(i));
if(i < actors.size() -1){
buf.append(" ");
}
}
CastLabel1.setText(buf.toString())

You should build the string you want to show first then set it to the text of the label:
StringBuilder sb = new StringBuilder();
boolean first = true;
for (String s : actors) {
if (!first)
sb.append(' ');
sb.append(s);
first = false;
}
CastLabel1.setText(sb.toString());
What you're currently doing is changing the entire label text during each iteration, so the final text is that of the last element in the list.

Update MySQL table using data from a text file through Java

I have a text file with four lines, each line contains comma separated values like below file
My file is:
Raj,raj34#myown.com,123455
kumar,kumar#myown.com,23453
shilpa,shilpa#myown.com,765468
suraj,suraj#myown.com,876567
and I have a MySQL table which contains four fields
firstname lastname email phno
---------- ---------- --------- --------
Raj babu raj34#hisown.com 2343245
kumar selva kumar#myown.com 23453
shilpa murali shilpa#myown.com 765468
suraj abd suraj#myown.com 876567
Now I want to update my table using the data in the above text file through Java.
I have tried using bufferedReader to read from the file and used split method using comma as delimiter and stored it in array. But it is not working. Any help appreciated.
This is what I have tried so far
void readingFile()
{
try
{
File f1 = new File("TestFile.txt");
FileReader fr = new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
String strln = null;
strln = br.readLine();
while((strln=br.readLine())!=null)
{
// System.out.println(strln);
arr = strln.split(",");
strfirstname = arr[0];
strlastname = arr[1];
stremail = arr[2];
strphno = arr[3];
System.out.println(strfirstname + " " + strlastname + " " + stremail +" "+ strphno);
}
// for(String i : arr)
// {
// }
br.close();
fr.close();
}
catch(IOException e)
{
System.out.println("Cannot read from File." + e);
}
try
{
st = conn.createStatement();
String query = "update sampledb set email = stremail,phno =strphno where firstname = strfirstname ";
st.executeUpdate(query);
st.close();
System.out.println("sampledb Table successfully updated.");
}
catch(Exception e3)
{
System.out.println("Unable to Update sampledb table. " + e3);
}
}
and the output i got is:
Ganesh Pandiyan ganesh1#myown.com 9591982389
Dass Jeyan jeyandas#myown.com 9689523645
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1
Gowtham Selvan gowthams#myown.com 9894189423
at TemporaryPackages.FileReadAndUpdateTable.readingFile(FileReadAndUpdateTable.java:35)
at TemporaryPackages.FileReadAndUpdateTable.main(FileReadAndUpdateTable.java:72)
Java Result: 1
#varadaraj:
This is the code of yours....
String stremail,strphno,strfirstname,strlastname;
// String[] arr;
Connection conn;
Statement st;
void readingFile()
{
try {
BufferedReader bReader= new BufferedReader(new FileReader("TestFile.txt"));
String fileValues;
while ((fileValues = bReader.readLine()) != null)
{
String[] values=fileValues .split(",");
strfirstname = values[0];
// strlastname = values[1];
stremail = values[1];
strphno = values[2];
System.out.println(strfirstname + " " + strlastname + " " + stremail +" "+ strphno);
}
bReader.close();
} catch (IOException e) {
System.out.println("File Read Error");
}
// for(String i : arr)
// {
// }
try
{
st = conn.createStatement();
String query = "update sampledb set email = stremail,phno =strphno where firstname = strfirstname ";
st.executeUpdate(query);
st.close();
System.out.println("sampledb Table successfully updated.");
}
catch(Exception e3)
{
System.out.println("Unable to Update sampledb table. " + e3);
}
}

What you are having looks like a CSV file, you may consider libraries like Super CSV to help you in reading and parsing the file.

you are getting ArrayIndexOutOfBoundException upon trying to access at index 1 , i.e at lastname field value, so check whether you have no data at index 1 for any of the list elements in your text file

try this
public class FileReaderTesting {
static String stremail;
static String strphno;
static String strfirstname;
static String strlastname;
static Connection conn;
static Statement st;
public static void main(String[] args) {
try {
BufferedReader bReader= new BufferedReader(new FileReader("C:\\fileName.txt"));
String fileValues;
while ((fileValues = bReader.readLine()) != null)
{
String[] values=fileValues .split(",");
strfirstname = values[0];
// strlastname = values[1];
stremail = values[1];
strphno = values[2];
System.out.println(strfirstname + " " + stremail +" "+ strphno);
st = conn.createStatement();
String query = "update sampledb set email = '"+stremail+"',pno = '"+strphno+"' where firstname = '"+strfirstname+"' ";
System.out.println(query);
st.executeUpdate(query);
st.close();
System.out.println("sampledb Table successfully updated.");
}
bReader.close();
} catch (IOException e) {
System.out.println("File Read Error");
}
catch(Exception e3)
{
System.out.println("Unable to Update sampledb table. " + e3);
}
}
}

How to improve the speed of this code?

I'm trying to import all googlebooks-1gram files into a postgresql database. I wrote the following Java code for that:
public class ToPostgres {
public static void main(String[] args) throws Exception {
String filePath = "./";
List<String> files = new ArrayList<String>();
for (int i =0; i < 10; i++) {
files.add(filePath+"googlebooks-eng-all-1gram-20090715-"+i+".csv");
}
Connection c = null;
try {
c = DriverManager.getConnection("jdbc:postgresql://localhost/googlebooks",
"postgres", "xxxxxx");
} catch (SQLException e) {
e.printStackTrace();
}
if (c != null) {
try {
PreparedStatement wordInsert = c.prepareStatement(
"INSERT INTO words (word) VALUES (?)", Statement.RETURN_GENERATED_KEYS
);
PreparedStatement countInsert = c.prepareStatement(
"INSERT INTO wordcounts (word_id, \"year\", total_count, total_pages, total_books) " +
"VALUES (?,?,?,?,?)"
);
String lastWord = "";
Long lastId = -1L;
for (String filename: files) {
BufferedReader input = new BufferedReader(new FileReader(new File(filename)));
String line = "";
while ((line = input.readLine()) != null) {
String[] data = line.split("\t");
Long id = -1L;
if (lastWord.equals(data[0])) {
id = lastId;
} else {
wordInsert.setString(1, data[0]);
wordInsert.executeUpdate();
ResultSet resultSet = wordInsert.getGeneratedKeys();
if (resultSet != null && resultSet.next())
{
id = resultSet.getLong(1);
}
}
countInsert.setLong(1, id);
countInsert.setInt(2, Integer.parseInt(data[1]));
countInsert.setInt(3, Integer.parseInt(data[2]));
countInsert.setInt(4, Integer.parseInt(data[3]));
countInsert.setInt(5, Integer.parseInt(data[4]));
countInsert.executeUpdate();
lastWord = data[0];
lastId = id;
}
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
However, when running this for ~3 hours it only placed 1.000.000 entries in the wordcounts table. When I check the amount of lines in the entire 1gram dataset it's 500.000.000 lines. So to import everything would take about 62.5 days, I can accept that it imports in about a week, but 2 months? I think I'm doing something seriously wrong here(I do have a server that runs 24/7, so I can actually run it for this long, but faster would be nice XD)
EDIT: This code is how I solved it:
public class ToPostgres {
public static void main(String[] args) throws Exception {
String filePath = "./";
List<String> files = new ArrayList<String>();
for (int i =0; i < 10; i++) {
files.add(filePath+"googlebooks-eng-all-1gram-20090715-"+i+".csv");
}
Connection c = null;
try {
c = DriverManager.getConnection("jdbc:postgresql://localhost/googlebooks",
"postgres", "xxxxxx");
} catch (SQLException e) {
e.printStackTrace();
}
if (c != null) {
c.setAutoCommit(false);
try {
PreparedStatement wordInsert = c.prepareStatement(
"INSERT INTO words (id, word) VALUES (?,?)"
);
PreparedStatement countInsert = c.prepareStatement(
"INSERT INTO wordcounts (word_id, \"year\", total_count, total_pages, total_books) " +
"VALUES (?,?,?,?,?)"
);
String lastWord = "";
Long id = 0L;
for (String filename: files) {
BufferedReader input = new BufferedReader(new FileReader(new File(filename)));
String line = "";
int i = 0;
while ((line = input.readLine()) != null) {
String[] data = line.split("\t");
if (!lastWord.equals(data[0])) {
id++;
wordInsert.setLong(1, id);
wordInsert.setString(2, data[0]);
wordInsert.executeUpdate();
}
countInsert.setLong(1, id);
countInsert.setInt(2, Integer.parseInt(data[1]));
countInsert.setInt(3, Integer.parseInt(data[2]));
countInsert.setInt(4, Integer.parseInt(data[3]));
countInsert.setInt(5, Integer.parseInt(data[4]));
countInsert.executeUpdate();
lastWord = data[0];
if (i % 10000 == 0) {
c.commit();
}
if (i % 100000 == 0) {
System.out.println(i+" mark file "+filename);
}
i++;
}
c.commit();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
I reached 1.5 million rows in about 15 minutes now. That's fast enough for me, thanks all!

JDBC connections have autocommit enabled by default, which carries a per-statement overhead. Try disabling it:
c.setAutoCommit(false)
then commit in batches, something along the lines of:
long ops = 0;
for(String filename : files) {
// ...
while ((line = input.readLine()) != null) {
// insert some stuff...
ops ++;
if(ops % 1000 == 0) {
c.commit();
}
}
}
c.commit();

If your table has indexes, it might be faster to delete them, insert the data, and recreate the indexes later.
Setting autocommit off, and doing a manual commit every 10 000 records or so (look into the documentation for a reasonable value - there is some limit) could speed up as well.
Generating the index/foreign key yourself, and keeping track of it should be faster than wordInsert.getGeneratedKeys(); but I'm not sure, whether it is possible from your content.
There is an approach called 'bulk insert'. I don't remember the details, but its a starting point for a search.

Write it to do threading, running 4 threads at the same time, or split it up in sections (read from config file) and distribute it to X machines and have them get the data togeather.

Use batch statements to execute multiple inserts at the same time, rather than one INSERT at a time.
In addition I would remove the part of your algorithm which updates the word count after each insert into the words table, instead just calculate all of the word counts once inserting the words is complete.

Another approach would be to do bulk inserts rather than single inserts. See this question Whats the fastest way to do a bulk insert into Postgres? for more information.

Create threads
String lastWord = "";
Long lastId = -1L;
PreparedStatement wordInsert;
PreparedStatement countInsert ;
public class ToPostgres {
public void main(String[] args) throws Exception {
String filePath = "./";
List<String> files = new ArrayList<String>();
for (int i =0; i < 10; i++) {
files.add(filePath+"googlebooks-eng-all-1gram-20090715-"+i+".csv");
}
Connection c = null;
try {
c = DriverManager.getConnection("jdbc:postgresql://localhost/googlebooks",
"postgres", "xxxxxx");
} catch (SQLException e) {
e.printStackTrace();
}
if (c != null) {
try {
wordInsert = c.prepareStatement(
"INSERT INTO words (word) VALUES (?)", Statement.RETURN_GENERATED_KEYS
);
countInsert = c.prepareStatement(
"INSERT INTO wordcounts (word_id, \"year\", total_count, total_pages, total_books) " +
"VALUES (?,?,?,?,?)"
);
for (String filename: files) {
new MyThread(filename). start();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
class MyThread extends Thread{
String file;
public MyThread(String file) {
this.file = file;
}
#Override
public void run() {
try {
super.run();
BufferedReader input = new BufferedReader(new FileReader(new File(file)));
String line = "";
while ((line = input.readLine()) != null) {
String[] data = line.split("\t");
Long id = -1L;
if (lastWord.equals(data[0])) {
id = lastId;
} else {
wordInsert.setString(1, data[0]);
wordInsert.executeUpdate();
ResultSet resultSet = wordInsert.getGeneratedKeys();
if (resultSet != null && resultSet.next())
{
id = resultSet.getLong(1);
}
}
countInsert.setLong(1, id);
countInsert.setInt(2, Integer.parseInt(data[1]));
countInsert.setInt(3, Integer.parseInt(data[2]));
countInsert.setInt(4, Integer.parseInt(data[3]));
countInsert.setInt(5, Integer.parseInt(data[4]));
countInsert.executeUpdate();
lastWord = data[0];
lastId = id;
}
} catch (NumberFormatException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}