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how to find control MySQL Exceptions

basically i have a web app in java ee with MySql DB, in my MySQl i have an ID column which is unique. now if user inputed an ID that already exist in there it pops Duplicate entry 'UserID' for key 'UID_UNIQUE', i found that error code 612 is for Duplicate name in mysql. so my question is how to get the Mysql error code and how can i pass the user that ID has already been taken
here is my java code for inserting user info to my db
public void getData(String FName,String LName,
HttpServletRequest request, HttpServletResponse response){
PrintWriter out = null;
try{
int affectedRows;
out = response.getWriter();
String query = "INSERT INTO `duckdb`.`userstb` (`UFN`, `ULN`, `UID`) VALUES ('"+FName+"', '"+LName+"', '"+Uname+"')";
affectedRows = st.executeUpdate(query);
if (affectedRows == 0) {
throw new SQLException("Creating user failed, no rows affected.");
}
}catch(Exception ex){
System.out.println(ex);
}
}

You should catch SQLIntegrityViolationException, not just Exception. That's what it's for.
You certainly should not just parse the error message. It could be in another language for example.
At the very least you should catch SQLException and examine the SQL error code, although that will be vendor-specific.

usually we use next() . with (while or if ) to clause and use the Java side to simply check if this query returned any results:
such as :
Connection con = DatabaseConnection.getConnection();
PreparedStatement ps =
con.prepareStatement
("SELECT questid FROM completedQuests WHERE characterid = ? AND questid = ?");
ps.setInt (1, characterId);
ps.setInt (2, questId);
ResultSet rs = ps.executeQuery();
if (rs.next()) {
// Quest already completed
} else {
// Quest not completed yet
}

not exactly the way i expected but it solved my problem, thought somebody else could use it too.
System.out.println(ex);
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
ex.printStackTrace(pw);
String error = sw.toString();
if(error.indexOf("Duplicate Entry") != -1)
out.print(error);
System.out.println("PW: " + error);

brother I'm trying to help here . See I always do that validation with php,java ..etc , I will explain it very clear . You just need to write a query that (" Select * from userstb where FName = ' " + FName +" ' ") check if returns a value that means the FName already exist if not that means it's OK to register that . here completely simple example
Statement stmt = con.createStatement();
String SQL = "SELECT * From tableName WHERE FName = ' "+FName+" ' ";
ResultSet rs = stmt.executeQuery(SQL);
if(rs.next()){
System.out.println("the Name is already registered in DB ");
}else
{
//write the query to register the name
}
}

Pull string from sql to java

I am trying to pull a first name and last name from a table in my SQL database. The queries work fine in SQL without the "as First" part and I know the db connection is fine since it works in every other part of the code.
The error I receive is that table "First" does not exist, but it should be looking at firstName and lastName for the table names, not First and Last.
Its inside of a for loop with "i", but those values are correct, playerid = i exists.
try {
String query2 = " SELECT firstName as First from player "
+ "WHERE playerid = ?";
PreparedStatement st2 = db.conn.prepareStatement(query);
st2.setInt(1, i);
ResultSet rs2 = st2.executeQuery();
if (rs2.next()) {
setFirstName(rs2.getString("First"));
}
String query3 = " SELECT lastName as Last from player "
+ "WHERE playerid = ?";
PreparedStatement st3 = db.conn.prepareStatement(query);
st3.setInt(1, i);
ResultSet rs3 = st3.executeQuery();
if (rs3.next()) {
setLastName(rs3.getString("Last"));
}
}
catch (SQLException e) {
e.printStackTrace();
}

Change your code into something like this:
PreparedStatement ps = null;
try {
ps = db.conn.prepareStatement("SELECT firstName, lastName from player "
+ "WHERE playerid = ?");
for (int i = 0; i < MAX_PLAYERS /*<- or what is the loop condition?*/; i++) {
ps.setInt(1, i);
ResultSet rs = ps.executeQuery();
if (rs.next()) {
// should these methods really be called within a loop?
setFirstName(rs.getString("firstName"));
setLastName(rs.getString("lastName"));
}
rs.close();
}
} catch (SQLException e) {
throw new RuntimeException(e);
} finally {
if (ps != null) {
ps.close();
}
}
Some considerations:
When you're using a PreparedStatement within a loop, you should create the statement once, outside of the loop and then only re-assign the bind variable(s) during each iteration.
You should minimize the number of queries you run against the DB; in your case you should select both the first and last name column in a single query.
It is important to close the resources you open up (the PreparedStatement in this case). My example shows how this is usually done (in the finally block) pre Java 7. Use the try-with-resources statement if you're using a newer Java version.

setString for prepared statement not working

I am trying to use the setString(index, parameter) method for Prepared Statements in order to create a ResultSet but it doesn't seem to be inserting properly. I know the query is correct because I use the same one (minus the need for the setString) in a later else. Here is the code I currently have:
**From what I understand, the ps.setString(1, "'%" + committeeCode + "%'"); is supposed to replace the ? in the query but my output says otherwise. Any help is appreciated.
public String getUpcomingEvents(String committeeCode) throws SQLException{
Context ctx = null;
DataSource ds = null;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
StringBuilder htmlBuilder = new StringBuilder();
String html = "";
try {
ctx = new InitialContext();
ds = (DataSource) ctx.lookup("java:ConnectDaily");
conn = ds.getConnection();
if(committeeCode != null){
//get all events
String queryStatement = "SELECT " +
.......
"WHERE c.calendar_id = ci.calendar_id AND c.short_name LIKE ? " +
"AND ci.style_id = 0 " +
"AND ci.starting_date > to_char(sysdate-1, 'J') " +
"AND ci.item_type_id = cit.item_type_id " +
"ORDER BY to_date(to_char(ci.starting_date), 'J')";
ps = conn.prepareStatement(queryStatement);
ps.setString(1, "'%" + committeeCode + "%'");
System.out.println(queryStatement);
rs = ps.executeQuery();
if (rs != null){
while(rs.next()){
String com = rs.getString("name");
String comID = rs.getString("short_name");
String startTime = rs.getString("starting_time");
String endTime = rs.getString("ending_time");
String name = rs.getString("contact_name");
String desc = rs.getString("description");
String info = rs.getString("contact_info");
String date = rs.getString("directory");
htmlBuilder.append("<li><a href='?com="+committeeCode+"&directory=2014-09-10'>"+com+" - "+ date +" - "+startTime+" - "+endTime+"</a> <!-- Link/title/date/start-end time --><br>");
htmlBuilder.append("<strong>Location: </strong>"+comID+"<br>");
htmlBuilder.append("<strong>Dial-In:</strong>"+com+"<br>");
htmlBuilder.append("<strong>Part. Code:</strong>"+info+"<br>");
htmlBuilder.append("<a href='http://nyiso.webex.com'>Take me to WebEx</a>");
htmlBuilder.append("</li>");
}
}
html = htmlBuilder.toString();
.
.
.
}catch (NamingException e) {
e.printStackTrace();
//log error and send error email
} catch (SQLException e) {
e.printStackTrace();
//log error and send error email
}finally{
//close all resources here
ps.close();
rs.close();
conn.close();
}
return html;
}
}
Output
14:18:22,979 INFO [STDOUT] SELECT to_char(to_date(to_char(ci.starting_date), 'J'),'mm/dd/yyyy') as start_date, to_char(to_date(to_char(ci.ending_date), 'J'),'mm/dd/yyyy') as end_date, to_char(to_date(to_char(ci.starting_date), 'J'),'yyyy-mm-dd') as directory, ci.starting_time, ci.ending_time, ci.description, cit.description as location, c.name, c.short_name, ci.add_info_url, ci.contact_name, ci.contact_info FROM calitem ci, calendar c, calitemtypes cit WHERE c.calendar_id = ci.calendar_id AND c.short_name LIKE ? AND ci.style_id = 0 AND ci.starting_date > to_char(sysdate-1, 'J') AND ci.item_type_id = cit.item_type_id ORDER BY to_date(to_char(ci.starting_date), 'J')

There is no need for the quotes in setString:
ps.setString(1, "%" + committeeCode + "%");
This method will bind the specified String to the first parameter. It will not change the original query String saved in queryStatement.

The placeholder remains as part of the SQL text.
The bind value is passed when the statement is executed; the actual SQL text is not modified. (This is one of the big advantages of prepared statements: the same exact SQL text is reused, and we avoid the overhead of a hard parse.
Also note that you are including single quotes within the value, which is a bit odd.
If the bind placeholder were to be replaced in the SQL text, assuming committeeCode contains foo, the equivalent SQL text would be:
AND c.short_name LIKE '''%foo%'''
which will match only c.short_name values that begin and end with a single quote, and contain the string foo.
(This looks more like Oracle SQL syntax than it does MySQL.)

As we know that in setString we can pass string value only, So even if we write the code like this:
String param="'%"+committeeCode+"%'";
And if you print the value of param it will throw error, Hence you cannot use it as well in prepared statement.
You need to modify modify it little bit as:
String param="%"+committeeCode+"%";(Simpler one, other way can be used)
ps.setString(1,param);

A lock could not obtained within the time requested issue

The title is the error I'm getting, when I click load my program freezes. I assume it's because I'm doing a statement inside a statement, but from what I see it's the only solution to my issue. By loading, I want to just repopulate the list of patients, but to do so I need to do their conditions also. The code works, the bottom method is what I'm trying to fix. I think the issue is that I have 2 statements open but I am not sure.
load:
public void DatabaseLoad()
{
try
{
String Name = "Wayne";
String Pass= "Wayne";
String Host = "jdbc:derby://localhost:1527/Patients";
Connection con = DriverManager.getConnection( Host,Name, Pass);
PatientList.clear();
Statement stmt8 = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
String SQL8 = "SELECT * FROM PATIENTS";
ResultSet rs8 = stmt8.executeQuery( SQL8 );
ArrayList<PatientCondition> PatientConditions1 = new ArrayList();
while(rs8.next())
{
PatientConditions1 = LoadPatientConditions();
}
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
String SQL = "SELECT * FROM PATIENTS";
ResultSet rs = stmt.executeQuery( SQL );
while(rs.next())
{
int id = (rs.getInt("ID"));
String name = (rs.getString("NAME"));
int age = (rs.getInt("AGE"));
String address = (rs.getString("ADDRESS"));
String sex = (rs.getString("SEX"));
String phone = (rs.getString("PHONE"));
Patient p = new Patient(id, name, age, address, sex, phone,
PatientConditions1);
PatientList.add(p);
}
UpdateTable();
UpdateAllViews();
DefaultListModel PatientListModel = new DefaultListModel();
for (Patient s : PatientList) {
PatientListModel.addElement(s.getAccountNumber() + "-" + s.getName());
}
PatientJList.setModel(PatientListModel);
}
catch(SQLException err)
{
System.out.println(err.getMessage());
}
}
This is the method that returns the ArrayList of patient conditions
public ArrayList LoadPatientConditions()
{
ArrayList<PatientCondition> PatientConditionsTemp = new ArrayList();
try
{
String Name = "Wayne";
String Pass= "Wayne";
String Host = "jdbc:derby://localhost:1527/Patients";
Connection con = DriverManager.getConnection( Host,Name, Pass);
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
String SQL = "SELECT * FROM PATIENTCONDITIONS";
ResultSet rs5 = stmt.executeQuery( SQL );
int e = 0;
while(rs5.next())
{
e++;
String ConName = (rs5.getString("CONDITION"));
PatientCondition k = new PatientCondition(e,ConName);
PatientConditionsTemp.add(k);
}
}
catch(SQLException err)
{
System.out.println(err.getMessage());
}
return PatientConditionsTemp;
}

I had a similar problem.
I was connecting to derby db hosted on local server.
I created 2 simultaneous connections:
With squirrel
With ij tool
When a connection makes a modification on a table, it first gets a lock for the particular table.
This lock is released by the connection only after committing the transaction.
Thus if the second connection tries to read/write the same table, a msg prompts saying:
ERROR 40XL1: A lock could not be obtained within the time requested
To fix this, the connection which modified the table has to commit its transaction.
Hope this helps !

Here is a good place to start: http://wiki.apache.org/db-derby/LockDebugging

You need to close your statement and result set as well so that when you restart your program they won't be open. Add stmt.close(); and rs.close(); at the end of your lines of code within the try and catch statement.

Why could you not use the same connection object to do both the queries?
Like pass that connection object to the LoadPatientConditions() as a parameter and use it there.

Insert CLOB into Oracle database

My question is: How do you get around the ORA-01704: string literal too long error when inserting (or doing anything in queries) with CLOBs?
I want to have a query like this:
INSERT ALL
INTO mytable VALUES ('clob1')
INTO mytable VALUES ('clob2') --some of these clobs are more than 4000 characters...
INTO mytable VALUES ('clob3')
SELECT * FROM dual;
When I try it with actual values though I get ORA-01704: string literal too long back. This is pretty obvious, but how do I insert clobs (or execute any statement at all with a clob)?
I've tried looking at this question, but I don't think it has what I'm looking for. The clobs I have are in a List<String> and I iterate through them to make the statement. My code as it is follows:
private void insertQueries(String tempTableName) throws FileNotFoundException, DataException, SQLException, IOException {
String preQuery = " into " + tempTableName + " values ('";
String postQuery = "')" + StringHelper.newline;
StringBuilder inserts = new StringBuilder("insert all" + StringHelper.newline);
List<String> readQueries = getDomoQueries();
for (String query : readQueries) {
inserts.append(preQuery).append(query).append(postQuery);
}
inserts.append("select * from dual;");
DatabaseController.getInstance().executeQuery(databaseConnectionURL, inserts.toString());
}
public ResultSet executeQuery(String connection, String query) throws DataException, SQLException {
Connection conn = ConnectionPool.getInstance().get(connection);
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(query);
conn.commit();
ConnectionPool.getInstance().release(conn);
return rs;
}

You are making it way to complicated.
Use a PreparedStatement and addBatch() for each clob in your list:
String sql = "insert into " + tempTableName + " values (?)";
PreparedStatement stmt = connection.prepareStatement(sql);
for (String query : readQueries) {
stmt.setCharacterStream(1, new StringReader(query), query.lenght());
stmt.addBatch();
}
stmt.exececuteBatch();
No messing around with escaping strings, no problem with the length of the literals, no need to create temporary clobs. And most probably just as fast as using a single INSERT ALL statement.
If you are using a current driver (> 10.2) then I think the setCharacterStream() call and the creation of the Reader is not necessary either. A simple setString(1, query) will most probably work as well.

You'll need to use bind variables rather than building a SQL statement using string concatenation. This will be beneficial from a security, performance, and robustness standpoint as well since it will reduce the risk of SQL injection attacks, decrease the amount of time Oracle has to spend doing hard parses of the SQL statement, and will eliminate the potential that there is a special character in the string that causes an invalid SQL statement to get generated (i.e. a single quote).
I would expect that you want something like
private void insertQueries(String tempTableName) throws FileNotFoundException, DataException, SQLException, IOException {
String preQuery = " into " + tempTableName + " values (?)" + StringHelper.newline;
StringBuilder inserts = new StringBuilder("insert all" + StringHelper.newline);
List<String> readQueries = getDomoQueries();
for (String query : readQueries) {
inserts.append(preQuery);
}
inserts.append("select * from dual");
Connection conn = ConnectionPool.getInstance().get(connection);
PreparedStatement pstmt = conn.prepareStatement(
inserts);
int i = 1;
for (String query : readQueries) {
Clob clob = CLOB.createTemporary(conn, false, oracle.sql.CLOB.DURATION_SESSION);
clob.setString(i, query);
pstmt.setClob(i, clob);
i = i + 1;
}
pstmt.executeUpdate();
}

BLOB (Binary Large Objects ) and CLOB(Character large objects) are special datatypes and can hold the large chunks of data in form of objects or text. Blob and Clob objects persist the data of the objects into the database as a stream.
An example piece of code:
public class TestDB {
public static void main(String[] args) {
try {
/** Loading the driver */
Class.forName("com.oracle.jdbc.Driver");
/** Getting Connection */
Connection con = DriverManager.getConnection("Driver URL","test","test");
PreparedStatement pstmt = con.prepareStatement("insert into Emp(id,name,description)values(?,?,?)");
pstmt.setInt(1,5);
pstmt.setString(2,"Das");
// Create a big CLOB value...AND inserting as a CLOB
StringBuffer sb = new StringBuffer(400000);
sb.append("This is the Example of CLOB ..");
String clobValue = sb.toString();
pstmt.setString(3, clobValue);
int i = pstmt.executeUpdate();
System.out.println("Done Inserted");
pstmt.close();
con.close();
// Retrive CLOB values
Connection con = DriverManager.getConnection("Driver URL","test","test");
PreparedStatement pstmt = con.prepareStatement("select * from Emp where id=5");
ResultSet rs = pstmt.executeQuery();
Reader instream = null;
int chunkSize;
if (rs.next()) {
String name = rs.getString("name");
java.sql.Clob clob = result.getClob("description")
StringBuffer sb1 = new StringBuffer();
chunkSize = ((oracle.sql.CLOB)clob).getChunkSize();
instream = clob.getCharacterStream();
BufferedReader in = new BufferedReader(instream);
String line = null;
while ((line = in.readLine()) != null) {
sb1.append(line);
}
if (in != null) {
in.close();
}
// this is the clob data converted into string
String clobdata = sb1.toString();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

From Oracle document
You must bear in mind the following automatic switching of the input mode for large data.
There are three input modes as follows: Direct binding, Stream binding, and LOB binding.
For PL/SQL statements
The setBytes and setBinary stream methods use direct binding for data less than 32767 bytes.
The setBytes and setBinaryStream methods use LOB binding for data larger than 32766 bytes.
The setString, setCharacterStream, and setAsciiStream methods use direct binding for data smaller than 32767 bytes in the database character set.
The setString, setCharacterStream, and setAsciiStream methods use LOB binding for data larger than 32766 bytes in the database character set.
The setBytesForBlob and setStringForClob methods, present in the oracle.jdbc.OraclePreparedStatement interface, use LOB binding for any data size.
Follow is a example for put a file content into a input CLOB parameter of a PLSQL procedure:
public int fileToClob( FileItem uploadFileItem ) throws SQLException, IOException
{
//for using stmt.setStringForClob method, turn the file to a big String
FileItem item = uploadFileItem;
InputStream inputStream = item.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader( inputStream );
BufferedReader bufferedReader = new BufferedReader( inputStreamReader );
StringBuffer stringBuffer = new StringBuffer();
String line = null;
while((line = bufferedReader.readLine()) != null) { //Read till end
stringBuffer.append(line);
stringBuffer.append("\n");
}
String fileString = stringBuffer.toString();
bufferedReader.close();
inputStreamReader.close();
inputStream.close();
item.delete();
OracleCallableStatement stmt;
String strFunction = "{ call p_file_to_clob( p_in_clob => ? )}";
stmt= (OracleCallableStatement)conn.prepareCall(strFunction);
try{
SasUtility servletUtility = sas.SasUtility.getInstance();
stmt.setStringForClob(1, fileString );
stmt.execute();
} finally {
stmt.close();
}
}

Me, I like to use the classes from java.sql.* package, not oracle.* stuff. For me the simple approach
Connection con = ...;
try (PreparedStatement pst = con.prepareStatement(
"insert into tbl (other_fld, clob_fld) values (?,?)", new String[]{"tbl_id"});
) {
Clob clob = con.createClob();
readIntoClob(clob, inputStream);
pst.setString(1, "other");
pst.setClob(2, clob);
pst.executeUpdate();
try (ResultSet rst = pst.getGeneratedKeys()) {
if (rst == null || !rst.next()) {
throw new Exception("error with getting auto-generated key");
}
id = rst.getBigDecimal(1);
}
stopped working when testing (current tomcat, jdbc) moved into production (stuck in Tomcat6 for stupid reasons). con.createClob() returns null for reasons unknown in that version, so I had to do this double-take (It took me ages to figure out so I'm sharing here...)
try (PreparedStatement pst = con.prepareStatement(
"insert into tbl (other_fld) values (?)", new String[]{"tbl_id"});
PreparedStatement getClob= con.prepareStatement(
"select clob_fld from tbl where tbl_id = ? for update");
) {
Clob clob = con.createClob();
readIntoClob(clob, inputStream);
pst.setString(1, "other");
pst.executeUpdate();
try (ResultSet rst = pst.getGeneratedKeys()) {
if (rst == null || !rst.next()) {
throw new Exception("error with getting auto-generated key");
}
id = rst.getBigDecimal(1);
}
// fetch back fresh record, with the Clob
getClob.setBigDecimal(1, id);
getClob.execute();
try (ResultSet rst = getClob.getResultSet()) {
if (rst == null || !rst.next()) {
throw new Exception("error with fetching back clob");
}
Clob c = rst.getClob(1);
// Fill in data
readIntoClob(c, stream);
// that's all
}
} catch (SQLException) {
...
}
for completeness here's
// Read data from an input stream and insert it in to the clob column
private static void readIntoClob(Clob clob, InputStream stream) {
try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(stream))) {
char[] buffer = new char[CHUNK_BUFFER_SIZE];
int charsRead;
try (Writer wr = clob.setCharacterStream(1L)) {
// Loop for reading of chunk of data and then write into the clob.
while ((charsRead = bufferedReader.read(buffer)) != -1) {
wr.write(buffer, 0, charsRead);
}
} catch (SQLException | IOException ex) {
...
}
}
}
which is from elsewhere on SO, thanks.

Check out some CLOB related samples on github.