Develop Reference

Update query not working in preparedStatements Java

I am writing this program in which I am using preparedStatements to make changes to an SQL Database. However, the UPDATE query is not working.
Here is the code:
package financials;
import java.net.URL;
import java.util.ResourceBundle;
import java.sql.*;
public void initialize(URL url, ResourceBundle rb) {
try{
Class.forName("com.mysql.cj.jdbc.Driver");
con=DriverManager.getConnection("jdbc:mysql://localhost/finances","root","P#ssword");
con.setAutoCommit(true);// TODO
}
catch(Exception ae)
{
System.out.println("Error in connection !");
}
#FXML
private void SaveOrAdd(ActionEvent event) { //This is button which on click executes the following code
String Action=save.getText();
if(Action.equals("Add Account"))
{
String SBNumber=LinkedSB.getText();
String newAccountType=AccountTypeF.getText();
String newFHolder=FHolderF.getText();
String newSHolder=SHolderF.getText();
String newTHolder=THolderF.getText();
String Bankcode=BankCodeF.getText();
if(newAccountType.equals("")||newFHolder.equals("")||newSHolder.equals("")||newTHolder.equals(""))
{
update.setText("Please fill in all the fields !");
}
else
{
try
{
PreparedStatement pst=con.prepareStatement("INSERT INTO banklines (Bank_Code,Linked_SB_Account,Sb_Account_Type,First_Holder,Second_Holder,Third_Holder) VALUES (?,?,?,?,?,?)");
pst.setString(1,Bankcode);
pst.setString(2,SBNumber);
pst.setString(3,newAccountType);
pst.setString(4,newFHolder);
pst.setString(5,newSHolder);
pst.setString(6,newTHolder);
int a=pst.executeUpdate();
System.out.println(a); //This returns a 1
}
catch(Exception ae)
{
update.setText("Update Failed !");
}
}}
else
{
String SBNumber=LinkedSB.getText();
String newAccountType=AccountTypeF.getText();
String newFHolder=FHolderF.getText();
String newSHolder=SHolderF.getText();
String newTHolder=THolderF.getText();
String Bankcode=BankCodeF.getText();
if(newAccountType.equals("")||newFHolder.equals("")||newSHolder.equals("")||newTHolder.equals(""))
{
update.setText("Please fill in all the fields !");
}
else //This is the block in concern
{
try
{
//Here is where the issue starts !
PreparedStatement pst2=con.prepareStatement("UPDATE banklines SET Sb_Account_Type=?,First_Holder=?,Second_Holder=?,Third_Holder=? WHERE Linked_SB_Account=? AND Bank_Code=?");
pst2.setString(1,newAccountType);
pst2.setString(2,newFHolder);
pst2.setString(3,newSHolder);
pst2.setString(4,newTHolder);
pst2.setString(5,SBNumber);
pst2.setString(6,Bankcode);
pst2.executeUpdate();
int a=pst2.executeUpdate();
System.out.println(a); //This returns a 0
update.setText("Successfully Updated !");
}
catch(Exception ae)
{
update.setText("Update Failed !");
}
}
}
}
The problem is that no error is being thrown, that is, the output is always Successfully Updated. However, the changes are not being reflected on the database. I have tried executing the query UPDATE banklines SET Sb_Account_Type=?,First_Holder=?,Second_Holder=?,Third_Holder=? WHERE Linked_SB_Account=? AND Bank_Code=? separately as a query in mySQL workbench, and it returns no error. I have also ensured that no variable is left blank. In-spite of all this, the update is not working. What confused me even more is that the previous query in the if-else block, that is the INSERT query works perfectly, and the results are updated in the database as well.
I am using NetBeans 8.2 with jdk 1.8 and mysql-connector-java-8.0.21.
P.S. I have stuck to java naming conventions to the best of my knowledge, ensuring that I follow CamelCase notation wherever I could. Please edit my code or suggest changes if you feel that anything is wrong.

The column names of your insert statement don't match the order of the bind variables which means that your inserted record has the wrong account id values.
For example you set SBNumber as index 6 when it should be:
pst.setString(2,SBNumber);
It is also good practice to check the number of rows changed by updates so that you can make further asserts / checks on your actions:
int rows = pst.executeUpdate();
if (rows != 1) throw new RuntimeException("Failed to update account: "+ SBNumber);
In your case rows is set to 0 as the row to update is never found - because Linked_SB_Account is not matched.

Cannot parse file using JDBC

Im trying to parse a pipe delimited file and insert fields into a table. when i start the application nothing happens in my DB. My DB has 4 columns (account_name, command_name, and system_name, CreateDt). The file i am parsing has the date in the first row then extra data. The rows following i only need the first 3 fields in each the rest is extra data. the last row is the row count. i skipped the inserting date because for now but want to get back to it after at least able to insert the first 3 fields. I have little experience with parsing a file and storing data in a DB and have looked through jdbc examples to get to this point but im struggling and am sure there is a better way.
File Example
20200310|extra|extra|extra||
Mn1223|01192|windows|extra|extra|extra||
Sd1223|02390|linux|extra|extra|extra||
2
table format
account_name command_name system_name createDt
Mn1223 01192 windows 20200310
Sd1223 02390 linux 20200310
Code to parse and insert into DB
public List insertZygateData (List<ZygateEntity> parseData) throws Exception {
String filePath = "C:\\DEV\\Test_file.xlsx";
List<String> lines = Files.readAllLines(Paths.get(filePath));
// remove date and amount
lines.remove(0);
lines.remove(lines.size() - 1);
for (ZygateEntity zygateInfo : parseData){
new MapSqlParameterSource("account_name", zygateInfo.getAccountName())
.addValue("command_name", zygateInfo.getCommandName())
.addValue("system_name", zygateInfo.getSystemName())
.getValues();
}
return lines.stream()
.map(s -> s.split("[|]")).map(val -> new ZygateEntity(val[0],val[1],val[2])).collect(Collectors.toList());
}
public boolean cleantheTable() throws SQLException {
String sql = "INSERT INTO Landing.midrange_xygate_load (account_name,command_name,system_name)"+
"VALUES (:account_name,:command_name,:system_name)";
boolean truncated = false;
Statement stmt = null;
try {
String sqlTruncate = "truncate table Landing.midrange_xygate_load";
jdbcTemplate.execute(sqlTruncate);
truncated = true;
} catch (Exception e) {
e.printStackTrace();
truncated = false;
return truncated;
} finally {
if (stmt != null) {
jdbcTemplate.execute(sql);
stmt.close();
}
}
log.info("Clean the table return value :" + truncated);
return truncated;
}
}
Entity/Model
public ZygateEntity(String accountName, String commandName, String systemName){
this.accountName=accountName;
this.commandName=commandName;
this.systemName=systemName;
}
//getters and setters
#Override
public String toString() {
return "ZygateEntity [accountName=" + accountName + ", commandName=" + commandName + ", systemName=" + systemName + ", createDt=" + createDt +"]";
}
}

Taking a look at what you've provided, it seems you have a jumbled collection of bits of code, and while most of it is there, it's not all there and not quite all in the right order.
To get some kind of clarity, try to break down what it is you're doing into separate steps, and have a method that focuses on each step. In particular, you write
Im trying to parse a pipe delimited file and insert fields into a table
This naturally breaks down into two parts:
parsing the pipe-delimited file, and
inserting fields into a table.
For the first part, you seem to have most of the parts already in your insertZygateData method. In particular, this line reads all the lines of a file into a list:
List<String> lines = Files.readAllLines(Paths.get(filePath));
These lines then remove the first and last lines from the list of lines read:
// remove date and amount
lines.remove(0);
lines.remove(lines.size() - 1);
You then have some code that looks a bit out of place: this seems to be something to do with inserting into the database, but we haven't created our list of ZygateEntity objects as we haven't yet finished reading the file. Let's put this for loop to one side for the moment.
Finally, we take the list of lines we read, split them using pipes, create ZygateEntity objects from the parts and create a List of these objects, which we then return.
return lines.stream()
.map(s -> s.split("[|]")).map(val -> new ZygateEntity(val[0],val[1],val[2])).collect(Collectors.toList());
Putting this lot together, we have a useful method that parses the file, completing the first part of the task:
private List<ZygateEntity> parseZygateData() throws IOException {
String filePath = "C:\\DEV\\Test_file.xlsx";
List<String> lines = Files.readAllLines(Paths.get(filePath));
// remove date and amount
lines.remove(0);
lines.remove(lines.size() - 1);
return lines.stream()
.map(s -> s.split("[|]")).map(val -> new ZygateEntity(val[0],val[1],val[2])).collect(Collectors.toList());
}
(Of course, we could add a parameter for the file path to read, but in the interest of getting something working, it's OK to stick with the current hard-coded file path.)
So, we've got our list of ZygateEntity objects. How do we write a method to insert them into the database?
We can find a couple of the ingredients we need in your code sample. First, we need the SQL statement to insert the data. This is in your cleanThetable method:
String sql = "INSERT INTO Landing.midrange_xygate_load (account_name,command_name,system_name)"+
"VALUES (:account_name,:command_name,:system_name)";
We then have this loop:
for (ZygateEntity zygateInfo : parseData){
new MapSqlParameterSource("account_name", zygateInfo.getAccountName())
.addValue("command_name", zygateInfo.getCommandName())
.addValue("system_name", zygateInfo.getSystemName())
.getValues();
}
This loop creates a MapSqlParameterSource out of each ZygateEntity object, and then converts it to a Map<String, Object> by calling the getValues() method. But then it does nothing with this value. Effectively you're creating these objects and getting rid of them again without doing anything with them. This isn't ideal.
A MapSqlParameterSource is used with a Spring NamedParameterJdbcTemplate. Your code mentions a jdbcTemplate, which appears to be a field within the class that parses data and inserts into the database, but you don't show the full code of this class. I'm going to have to assume it's a NamedParameterJdbcTemplate rather than a 'plain' JdbcTemplate.
A NamedParameterJdbcTemplate contains a method update that takes a SQL string and a SqlParameterSource. We have a SQL string, and we're creating MapSqlParameterSource objects, so we can use these to carry out the insert. There's not a lot of point in creating one of these MapSqlParameterSource objects only to convert it to a map, so let's remove the call to getValues().
So, we now have a method to insert the data into the database:
public void insertZygateData(List<ZygateEntity> parseData) {
String sql = "INSERT INTO Landing.midrange_xygate_load (account_name,command_name,system_name)"+
"VALUES (:account_name,:command_name,:system_name)";
for (ZygateEntity zygateInfo : parseData){
SqlParameterSource source = new MapSqlParameterSource("account_name", zygateInfo.getAccountName())
.addValue("command_name", zygateInfo.getCommandName())
.addValue("system_name", zygateInfo.getSystemName());
jdbcTemplate.update(sql, source);
}
}
Finally, let's take a look at your cleanThetable method. As with the others, let's keep it focused on one task: it looks like at the moment you're trying to delete the data out of the table and then insert it in the same method, but let's have it just focus on deleting the data as we've now got a method to insert the data.
We can't immediately get rid of the String sql = ... line, because the finally block in your code uses it. If stmt is not null, then you attempt to run the INSERT statement and then close stmt.
However, stmt is never assigned any value other than null, so it remains null. stmt != null is therefore always false, so the INSERT statement never runs. Your finally block never does anything, so you would be best off removing it altogether. With your finally block gone, you can also get rid of your local variable stmt and the sql string, leaving us with a method whose focus is to truncate the table:
public boolean cleantheTable() throws SQLException {
boolean truncated = false;
try {
String sqlTruncate = "truncate table Landing.midrange_xygate_load";
jdbcTemplate.execute(sqlTruncate);
truncated = true;
} catch (Exception e) {
e.printStackTrace();
truncated = false;
return truncated;
}
log.info("Clean the table return value :" + truncated);
return truncated;
}
I'll leave it up to you to write the code that calls these methods. I wrote some code for this purpose, and it ran successfully and inserted into a database.
So, in summary, no data was being written to your database because you were never making a call to the database to insert any. In your insertZygateData method you were creating the parameter-source objects but not doing anything useful with them, and in your cleanThetable method, it looked like you were trying to insert data, but your line jdbcTemplate.execute(sql) that attempted to do this never ran. Even if stmt wasn't null, this line wouldn't work as you didn't pass the parameter values in anywhere: you would get an exception from the database as it would be expecting values for the parameters but you never gave it any.
Hopefully my explanation gives you a way of getting your code working and helps you understand why it wasn't.

Where to put index-re-aliasing when re-indexing in the background?

I try to re-index an ES index with Java:
// reindex all documents from the old into the new index
QueryBuilder qb = QueryBuilders.matchAllQuery();
SearchResponse scrollResp = client.prepareSearch("my_index").setSearchType(SearchType.SCAN).setScroll(new TimeValue(600000)).setQuery(qb).setSize(100).execute().actionGet();
while (true) {
scrollResp = client.prepareSearchScroll(scrollResp.getScrollId()).setScroll(new TimeValue(600000)).execute().actionGet();
final int documentFoundCount = scrollResp.getHits().getHits().length;
// Break condition: No hits are returned
if (documentFoundCount == 0) {
break;
}
// otherwise add all documents which are found (in this scroll-search) to a bulk operation for reindexing.
logger.info("Found {} documents in the scroll search, re-indexing them via bulk now.", documentFoundCount);
BulkRequestBuilder bulk = client.prepareBulk();
for (SearchHit hit : scrollResp.getHits()) {
bulk.add(new IndexRequest(newIndexName, hit.getType()).source(hit.getSource()));
}
bulk.execute(new ActionListener<BulkResponse>() {
#Override public void onResponse(BulkResponse bulkItemResponses) {
logger.info("Reindexed {} documents from '{}' to '{}'.", bulkItemResponses.getItems().length, currentIndexName, newIndexName);
}
#Override public void onFailure(Throwable e) {
logger.error("Could not complete the index re-aliasing.", e);
}
});
}
// these following lines should only be executed if the re-indexing was successful for _all_ documents.
logger.info("Finished re-indexing all documents, now setting the aliases from the old to the new index.");
try {
client.admin().indices().aliases(new IndicesAliasesRequest().removeAlias(currentIndexName, "my_index").addAlias("my_index", newIndexName)).get();
// finally, delete the old index
client.admin().indices().delete(new DeleteIndexRequest(currentIndexName)).actionGet();
} catch (InterruptedException | ExecutionException e) {
logger.error("Could not complete the index re-aliasing.", e);
}
In general, this works, but the approach has one problem:
If there is a failure during re-indexing, e.g. it takes too long and is stopped by some transaction watch (it runs during EJB startup), the alias is re-set and the old index is nevertheless removed.
How can I do that alias-re-setting if and only if all bulk requests were successful?

You're not waiting until the bulk request finishes. If you call execute() without actionGet(), you end up running asynchronously. Which means you will start changing aliases and deleting indexes before the new index is completely built.
Also:
client.admin().indices().aliases(new IndicesAliasesRequest().removeAlias(currentIndexName, "my_index").addAlias("my_index", newIndexName)).get();
This should be ended with execute().actionGet() and not get(). that is probably why your alias is not getting set

Android application exits without any exception

I'm building an application that shows in a WebView some remote data that is cached in SQLite db. The data is being requested by JavaScript function from WebView via JavaScript interface.
When user types into an input element on the page, JavaScript function requests search result by calling Java function, which in turn fires a sql query. Results are then packaged in suitable JSON format and returned.
Fetching data works OK unless you type very quickly. If you type quick enough after few key presses the app quits WITHOUT any exceptions being thrown, it just goes back to home screen.
I have managed to narrow down the cause - commenting out the call to .query method prevents crashing, but renders app useless.
Is there a way to check what caused application to quit, another log or tool that could help?
Java function code:
public Lot[] getLotList(String query, int limitCount) {
...
...
String[] resultColumns = new String[] { LotsSearch._ID };
String queryWhere = LotsSearch.TABLE_NAME + " MATCH ?";
String[] queryArgs = new String[] { query + "*" };
String sortOrder = LotsSearch.COLUMN_NAME_NUMBER + " ASC, " + LotsSearch.COLUMN_NAME_TITLE + " ASC";
String limit = null;
Cursor cursor = null;
if (limitCount != -1)
limit = "0," + limitCount;
try {
cursor = mDb.query(LotsSearch.TABLE_NAME, resultColumns, queryWhere, queryArgs, null, null, sortOrder, limit);
if (cursor != null && cursor.moveToFirst()) {
result = new Lot[cursor.getCount()];
try {
int idColumnIndex = cursor.getColumnIndexOrThrow(LotsSearch._ID);
int lotId;
Lot lot;
do {
lotId = cursor.getInt(idColumnIndex);
lot = mLots.get(lotId);
if (lot != null)
result[index++] = lot;
} while (cursor.moveToNext());
} catch (IllegalArgumentException e) {
e.printStackTrace();
}
}
} catch (SQLiteException e) {
e.printStackTrace();
} finally {
if (cursor != null)
cursor.close();
}
...
...
return result;
}
UPDATE:
I have discovered that there is another log that could be accessed by issuing
logcat -b events
when the app crashes there is just one entry
I/am_proc_died( 59): [11473,com.example.app]
and when the app exits gracefuly this log shows set of entries:
I/am_finish_activity( 59): [1157978656,22,com.example.app/.MainActivity,app-request]
I/am_pause_activity( 59): [1157978656,com.example.app/.MainActivity]
I/am_on_paused_called(11473): com.example.app.MainActivity
I/am_destroy_activity( 59): [1157978656,22,com.example.app/.MainActivity]

I'd make a change to my auto search function. Namely, only perform the search if the user hasn't pressed a key for about 1/2 a second.
If you are typing fast, then this function is being executed several times right on top of itself, before the results are even able to come back. Meanwhile you are probably have too many cursor resources going at once causing the app to just completely fail.
update. If you consider it, typing 10 keys fairly quickly in a row could potentially mean that you have 10 different queries executing and parsing results... There could certainly be some deadlocking issues with the code that actually calls the getLotList method if it's spun multiple threads to try and update the UI. This can lead to some programs simply giving up the ghost not knowing what to do or even what thread to report the issue on.
Of course, all of that's hard to tell from the small snippet we have.

How to delete more than one record at a time in salesforce?

How do I delete more than one record at a time in salesforce?

Delete all Salesforce Account objects (up to the artificially imposed limitations per SF query on whatever the object happens to be):
delete new List<Account>([select Id from Account]);
Where "Account" is any Salesforce object (or custom object you've created). You can fine-tune the delete by adding the "WHERE" clause:
delete new List<Account>([select Id from Account where ... ])
Or the "LIKE" clause:
delete new List<Account>([select Id from Account where LastName like 'Jon%']);

Is this what you want?
Salesforce CRM -delete()

Here is a method in Java that would delete one row in salesforce.
Salesforce ID's are 18 character case sensitive keys. Every table has an id that is unique across the entire database. So you can delete by an id, and salesforce will know what table you are referring to.
public static boolean salesforceDevDeleteById(String id){
SalesforceConnector sf;
boolean deletesuccess = false;
try{
sf = new SalesforceConnector();
sf.login("youruser#yourhost.com",
"keyasdf", "keyasdf", "dev");
if (!id.equals("")){
DeleteResult[] deleteResults = sf.delete(new String[]{id});
for(DeleteResult r : deleteResults){
deletesuccess = r.isSuccess();
break;
}
}
else{
System.out.println("Failed to delete");
}
System.out.println("delete success: " + deletesuccess);
}
catch(Exception e){
e.printStackTrace();
System.out.println("error");
}
return deletesuccess;
}
Notice where it invokes the delete method. You can load a set of id's there.

psuedo:
List _list = new List();
_list.add(a);
_list.add(b);
delete(_list);