Develop Reference

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.

Why will Ucanaccess not delete my records?

I can connect to my access database and select, insert records etc. I am now trying to delete records and as far as I can see I am using the correct syntax. I have followed just about every tutorial I can find and they are not doing anything different that I can see.
String deleteSql = "DELETE FROM table1 WHERE sometext=? or sometext=?";
ps = module.getSupportConnection().prepareStatement(deleteSql);
ps.setString(1,"four");
ps.setString(2,"five");
int rs = ps.executeUpdate();
System.out.println(rs);
I have tried it without using int rs = .. but I used it just to see what the output was and it returns '2' which is what I was expecting as there are two records that meet the criteria used. It just wont delete the records and I cant see why. I dont get any errors when running the code. I appreciate this may not be a ucanaccess issue per se.

jOOQ problems with limit..offset - no values sets

I am trying to build a query using jOOQ, this is my test code:
DSLContext create = DSL.using(SQLDialect.DERBY);
String query = create.select().from(TABLE).limit(1).offset(0).getSQL()
I get as query:
select field1, field2...fieldN etc from TABLE offset ? rows fetch next ? rows only
the problem is ? in ? rows fetch next ? rows only it seems to ignore the values that i used in limit and offset to build the query, why?
I am trying to select the first row from the results and I am using jooq 3.4.1
Thanks for the help

Query.getSQL() returns your SQL string with ? as placeholders for your bind variables. The idea is that you can feed this statement to a PreparedStatement and then explicitly bind all variables, which are available through Query.getBindValues().
You can also have jOOQ inline all your bind variables, by calling Query.getSQL(ParamType) as such:
String sql = query.getSQL(ParamType.INLINED);

Preview sql result columns in java

Is there any way for 'previewing' sql select statements?
What I'm trying to do is to get the names of the columns that are returned by a sql statement without actually running the statement?
On application startup i need to know the column names, the problem is that some of the queries can run for awhile.

ResultSetMetaData may help
You still have to execute the query to get the meta data, but you may be able to alter add a restriction to the where clause which means it returns zero rows very quickly. For example you could append and 1 = 0 to the where clause.
The DBMS still has to do all the query parsing that it would normally do - it just means that the execution should hopefully fail very quickly

You didn't mention your DBMS, but the following works with the Postgres and Oracle JDBC drivers. I didn't test any other.
// the statement is only prepared, not executed!
PreparedStatement pstmt = con.prepareStatement("select * from foo");
ResultSetMetaData metaData = pstmt.getMetaData();
for (int i=1; i <= metaData.getColumnCount(); i++)
{
System.out.println(metaData.getColumnName(i));
}

Slow performance on Hibernate + Java but fast when I use TOAD with the same native Oracle query

I've detected a performance problem with hibernate and native queries on Oracle. When I execute a complex SQL query with several parameters on TOAD I get the result in miliseconds. However, when I execute the same query using Hibernate this time is incremented hugely (up to four seconds or even more).
My SQL query is rather complex, return an unique value (so, the problem is not related with the time necessary to instation classes) and it contains several parameters with the the format ':nameParameter'. This query is stored in a String. For example,
String myNamedNativeQuery = "select count(*) from tables "+
"where column1 = :nameParameter1 "+
"and column2 = :nameParameter2";
//actually my sentence is much more complex!!
When I execute the sentence on TOAD it is resolved in few miliseconds. But using this sentence with Hibernate
SQLQuery query = session.createSQLQuery("myNamedNativeQuery");
query.setParameter(nameParameter1, value1);
query.setParameter(nameParameter2, value2);
query.uniqueResult();
are necessary several seconds to get the same result.
I realized if I replaced the parameters directly on the native query and then I execute the sentence using Hibernate the time decreases drastically. It would be something like that:
String strQuery = session.getNamedQuery("myNamedNativeQuery").getQueryString();
myNamedNativeQuery = myNamedNativeQuery.replace("nameParameter1", value1);
myNamedNativeQuery = myNamedNativeQuery.replace("nameParameter2", value2);
SQLQuery query = session.createSQLQuery("myNamedNativeQuery");
query.uniqueResult();
Anybody knows what's happening??
Thanks in advance.
PS: The Oracle version is 9i and Hibernate 3.2

I think what's happening with this code :
SQLQuery query = session.createSQLQuery("myNamedNativeQuery");
query.setParameter(nameParameter1, value1);
query.setParameter(nameParameter2, value2);
query.uniqueResult();
is this:
at line 1 : a query plan is created based on some expected values for your named parameters.
at line 4 : the query is executed with value1 and value2, but those values are not "good values" for the query plan that was elaborate at line 1 and so, the database is executing a very inappropriate plan for the actual values and it takes a lot of time.
Why ?
Looking at the source code of HibernateSessionImpl.createSQLQuery(...) I found this line of code:
SQLQueryImpl query = new SQLQueryImpl(
sql,
this,
factory.getQueryPlanCache().getSQLParameterMetadata( sql )
);
which is calling getQueryPlanCache() with some parameterMetaData. I assume that this metadata is not good enough.

My answer to you is:
Remove all bind parameters and use StatelessSession instead of Session
Use SQLQuery instead of query with full SQL including parameter values
StatelessSession session = sessionFactory.openStatelessSession();
I had similar problem and till I get better solution,this is what I managed to make it work.
See Hibernate parameterized sql query slow and active oracle sessions

<property name = "hibernate.temp.use_jdbc_metadata_defaults">false</property>
Add this to your hibernate.cfg.xml or update your application properties file.