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Java prepared statement does not allow large strings in the where clause of the query

I am trying to retrieve data from DB2 using Java prepared statement
String select_statement = "SELECT * FROM schema_name.table_name where NME='xxx002' and LINE =7200 and FILE_NME='720001042021XYZ002' with ur";
try (Connection connection = DataBaseConnection.getGeoCarDBConnection_TESTDATA();
PreparedStatement ps = connection.prepareStatement(select_statement);) {
ResultSet rs = null;
rs = ps.executeQuery();
}
The problem I am facing is that I include the FILE_NME in the where clause of the query, as shown above, 0 rows are returned. But any other string fields can be passed and I get the desired number of rows.
Any integer fields in the where clause works too.
But only the string fields that are large(In this case, FILE_NME field) are not working. In the DB2 table, where I am pulling the data from, the FILE_NME field is of varchar(30).
Things that did not work for me was
String select_statement = "SELECT * FROM schema_name.table_name where NME='xxx002' and LINE =7200 and FILE_NME = ? with ur";
then I set the String value using,
ps.setString(1, "'720001042021XYZ002'")
ps.setString(1, "720001042021XYZ002")
Both did not work.
None of the google links were helpful. Have spent more than a day on it.
This code used to work flawlessly before, Even the java version hasn't changed(as per my knowledge)
I am running it in windows 10.
Java version : 1.8 ((build 1.8.0_221-b11))
I run the same query in the database client and it works.
Someone please help me or point me in the right direction. I don't know what I am missing
Thank in advance

The problem was that there was indeed no data, I was checking the same query in the database client in a different environment. I am closing this.

getGeneratedKeys() returns an Empty ResultSet

Hello there and thanks for reading.
I'm trying to retrieve the ID of the newly inserted data, but I always get an empty ResultSet.
Connection con = main.getCon();
String sqlCommand = "Insert Into Relations(name,explanation) values(?,?)";
PreparedStatement state =
con.prepareStatement(sqlCommand,Statement.RETURN_GENERATED_KEYS);
state.setString(1,name.getText());
state.setString(2,explanation.getText());
int affectedRows = state.executeUpdate();
assert (affectedRows>0);
ResultSet rs = state.getGeneratedKeys();
assert rs.next();
int instertedID= rs.getInt("ID");
Not sure what's wrong with it. Checked different samples online, but couldn't figure out what's my mistake.
I also tried it with Statement, but no luck with that either.
Point 1: the code runs smoothly and my data in inserted into the database.
Point 2: there are examples online for this very case, you can check it here:
https://www.baeldung.com/jdbc-returning-generated-keys
I just realized that my ResultSet wasn't empty, I had problem with using my debugger and that's why I thought it was empty.
As Mark Rotteveel mentioned in a comment, the problem was with "assert" statement.

The problem is your use of assert rs.next(). Assertions in Java are intended for checking invariants (eg during testing), but when you normally run Java, assert statements are not executed, they are only executed when explicitly enabling this with the -ea commandline option.
As a result, rs.next() is not called, so your result set is still positioned before the first row when you call rs.getInt(1). Instead use if (rs.next()) { ... }.

This is DB engine dependent. Some tips:
JDBC is low-level and not appropriate to program with
It's a complicated API. Use something that makes it easier: JDBI, or JOOQ. They may have abstractions over insertion that takes care of this stuff for you.
Some DB engines require that you list the column name
Try:
con.prepareStatement(sqlCommand, new String[] {"UNID"});
Some DB engines will only return generated values as direct resultset
Don't call .executeUpdate(); instead, call .executeQuery() which returns a ResultSet; check that one.
Something else
Post the exact table structure and DB engine you're working with if the above doesn't help.
Your code is broken
You can't create resource objects (once that must be closed) unless you do so safely, and you're not doing so safely. Use try-with-resources:
String sql = "INSERT INTO relations(name, explanation) VALUES (?, ?)";
try (Connection con = main.getCon();
PreparedStatement ps = con.prepareStatement(sql, new String[] {"unid"})) {
state.setString(1, name.getText());
state.setString(2, explanation.getText());
try (ResultSet rs = state.executeQuery()) {
if (!rs.next()) throw new SQLException("insert didn't return autogen?");
System.out.println(rs.getInt(1));
}
}
ResultSets, Statements, PreparedStatements, and Connections are all resources (must be closed!) - if you want to store one of those things in a field, you can do that, but only if the class that contains this field is itself a resource: It must have a close() method, it must implement AutoClosable, and you can then only make instances of this class with try-with-resources as above.
Failure to adhere to these rules means your app seems to work, but is leaking resources as it runs, thus, if you let it run long enough, it will start crashing. Also, your DB engine will grind to a halt as more and more connections are left open, stuck forever.

change the last line of code to this because the DBMS you are using may not support the getting value by column name so pass the index of that column:
int instertedID = rs.getInt(1);

String sqlCommand = "Insert Into Relations (name, explanation) values(?, ?)";
PreparedStatement state = con.prepareStatement(sqlCommand, Statement.RETURN_GENERATED_KEYS);
state.setString(1,name.getText());
state.setString(2,explanation.getText());
state.executeUpdate();
ResultSet resultSet = state.getGeneratedKeys();
if(resultSet.next()) {
System.out.println(resultSet.getInt(1)); //Indicate the corresponding column index value.
}

ResultSet update row is not working

I want to update raw in my ResultSet while I looping through the result set. Following is my code
try {
String query="SELECT * FROM smsmessage WHERE recipient = ? and sent_status = 'pending' LIMIT ? ";
PreparedStatement prepStmt = conn.prepareStatement(query);
prepStmt.setString(1,shortCode);
prepStmt.setInt(2, Integer.parseInt(batchSize));
ResultSet rs=prepStmt.executeQuery();
while (rs.next()) {
//update the selected message sent status to "sent" from "pending"
rs.updateString("sent_status","sent");
rs.updateRow();
}
} catch (SQLException e) {
log.error("MySQL exception",e);
}
What should be the possible reason for this?
I am getting following error
com.mysql.jdbc.NotUpdatable: Result Set not updatable. This result set
must come from a statement that was created with a result set type of
ResultSet.CONCUR_UPDATABLE, the query must select only one table, can
not use functions and must select all primary keys from that table.
See the JDBC 2.1 API Specification, section 5.6 for more details.This
result set must come from a statement that was created with a result
set type of ResultSet.CONCUR_UPDATABLE, the query must select only one
table, can not use functions and must select all primary keys from
that table. See the JDBC 2.1 API Specification, section 5.6 for more
details.

As the stacktrace tells, you have to create a statement that allows its resultset to be updateable:
PreparedStatement prepStmt= conn.prepareStatement(query,
ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
From the API of ResultSet (http://docs.oracle.com/javase/7/docs/api/java/sql/ResultSet.html):
A default ResultSet object is not updatable and has a cursor that moves forward only. Thus, you can iterate through it only once and only from the first row to the last row. It is possible to produce ResultSet objects that are scrollable and/or updatable. The following code fragment, in which con is a valid Connection object, illustrates how to make a result set that is scrollable and insensitive to updates by others, and that is updatable. See ResultSet fields for other options.
Statement stmt = con.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
ResultSet rs = stmt.executeQuery("SELECT a, b FROM TABLE2");
// rs will be scrollable, will not show changes made by others,
// and will be updatable

Well, you should start by carefully reading the error text:
com.mysql.jdbc.NotUpdatable: Result Set not updatable. This result
set must come from a statement that was created with a result set
type of ResultSet.CONCUR_UPDATABLE, the query must select only one
table, can not use functions and must select all primary keys from
that table. See the JDBC 2.1 API Specification, section 5.6 for more
details.
This means that the result set is not updateable. You can't update a result set that is not updateable.
It also says that this result set must come from a statement that was created with a result set type of ResultSet.CONCUR_UPDATABLE. This means that your statement - in this case a PreparedStatement, must be created with that option.
Finally, it directs you to the documentation. JDBC 2.1 is a bit outdated, and you can find all the relevant data in the usual J2SE Documentation. Let's start from the documentation for ResultSet. It says:
A default ResultSet object is not updatable and has a cursor that
moves forward only. Thus, you can iterate through it only once and
only from the first row to the last row. It is possible to produce
ResultSet objects that are scrollable and/or updatable. The following
code fragment, in which con is a valid Connection object, illustrates
how to make a result set that is scrollable and insensitive to updates
by others, and that is updatable. See ResultSet fields for other
options.
And the code fragment it shows is:
Statement stmt = con.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
ResultSet rs = stmt.executeQuery("SELECT a, b FROM TABLE2");
// rs will be scrollable, will not show changes made by others,
// and will be updatable
So you see, they are using a statement where you add two parameters, that enable you to scroll through the data and update it. But they are using a Statement rather than a PreparedStatement. Is this applicabe to PreparedStatement as well?
Going to the PreparedStatement documentation will not help you much, but wait, you are using the connection object to prepare the statement, perhaps it will help you?
Yes, indeed, there is a method in Connection that allows you to pass the parameters, just like the Statement in the example.
PreparedStatement prepareStatement(String sql,
int resultSetType,
int resultSetConcurrency)
throws SQLException
So now you must ask yourself, what kind of resultSetType do I need, and what kind of resultSetConcurrency?
Scrolling your statement is not necessary for your current question, so you can use the default. If you look at the documentation of the plain preparedStatement(String) you'll see:
Result sets created using the returned PreparedStatement object will
by default be type TYPE_FORWARD_ONLY and have a concurrency level of
CONCUR_READ_ONLY. The holdability of the created result sets can be
determined by calling getHoldability().
...which is why your initial prepared statement was not updatable, by the way. But anyway, it tells you that the default for the scrolling type is TYPE_FORWARD_ONLY.
What about the updating, which is the important part? Well, the options are CONCUR_READ_ONLY and CONCUR_UPDATABLE. So you need to use the second one. That's what the error message told you, after all.
Conclusion:
You need to use
PreparedStatement prepStmt = conn.prepareStatement(
query,
ResultSet.TYPE_FORWARD_ONLY,
ResultSet.CONCUR_UPDATABLE);
This will give you an updatable result set.
And this is how to find your answer from the error message that you get.

Reusing ResultSet

I need to run several queries in a row
Statement st = cnx.createStatement();
ResultSet rs = st.executeQuery( "SELECT [good stuff]");
// do something smart with rs
rs = st.execute( "SELECT [better stuff]");
// do something smarter with rs
rs = st.execute( "SELECT [best stuff]");
// you got it
try{ rs.close();} catch( SQLException ignore){};
try{ st.close();} catch( SQLException ignore){};
Is this a problem that the first two ResultSet are not properly closed or is it implicitely done during garbage collection?

As soon as you execute the 2nd query, the previous ResultSet is automatically closed. And as far as Garbage Collection is concerned, you don't have to worry about that. You can just have a stmt.close() at the end that's all. It will automatically close all the related ResultSet objects.
Take a look at : - ResultSet#close documentation, which says that: -
A ResultSet object is automatically closed by the Statement object
that generated it when that Statement object is closed, re-executed,
or is used to retrieve the next result from a sequence of multiple
results.
If you want to test, whether your resultset gets closed or not, you can use a while loop to iterate over the result set and inside the while loop, create another query and assign it to same result set. You will see that an Exception will be thrown..
ResultSet res = stmt.executeQuery("SELECT * FROM sometable");
while (res.next()) {
res.getString(1);
// Closes the previous `ResultSet`
res = stmt.executeQuery("SELECT * FROM othertable");
}
So, in the above code, on the 2nd iteration, you will get an Exception: - Cannot perform operation after ResultSet is closed

I don't know what's your problem, but if you have some problems to run this code, you can try to close connection and open other to make the second query. Some database products, like SQLite, only admit one open connection. If you have any problem with database access, you should try that.

Java generating query from resultSet and executing the new query

I am trying to use some query result to generate another query and execute the new query but that does not seem to work. The second query is not being executed. Can someone please tell me why? This is that part of the code.
Statment stmt = connnection.createStatement();
Statment stmt2 = connnection.createStatement();
ResultSet r = stmt.executeQuery("Select * from employees");
while (r.next()) {
String Str = "Select name from employees where employeeId = " + (r.getInt(3) + 1);
System.out.println(str);
query = stmt2.executeQuery(str);
System.out.println(query.getString(1));}
The right query seems to be generated, but just won't execute. Is there a reason why this is so. BTW "query" is declared as resultset.
Thanks

you can only have one statement executing at one moment in time against one database connection -- so you can either open another database connection and execute the second statement in the 2nd connection, or iterate through the resultset from first statement and store the employees database id's (e.g. in an array/collection) then close that statement and run the second one, this time retrieving the id's from the array/collection you saved them in.