Re: JDBC_FreeResult - Free resultset and preparedStatement

Hey Scott,
I commented out the JDBC_FreeResult(myRS) statemetn that is in my program
and tried to run the program again. This time it executed successfully
(including execution of the second call to this sub-proc). I'm a bit lost
on what the cause of problem is if it is not cause by JDBC_FreeResult
dealloacted the PreparedStatement.


"hockchai Lim" <lim.hock-chai@xxxxxxxxxxxxxxx> wrote in message
news:mailman.6344.1283963130.2619.rpg400-l@xxxxxxxxxxxxxxx

Thanks Scott, I must miss interpreted the code.

I'll dig more into the cause of the problem that I'm encountering below:

I've a sub-proc with code like this:
JDBC_SetLong(addressSelectPS(connIdx) :1 :piWGINTS.unii);
myRS = JDBC_ExecPrepQry(addressSelectPS(connIdx));
if myRS <> *null;
if jdbc_nextRow(myRS);
myRecExist = *on;
endif;
JDBC_FreeResult(myRS);
endif;


This sub-proc works fine on the first execution. But it get error below
when it is executed on the second time. The error happened when it
executes the JDBC_SetLong(addressSelectPS(connIdx) :1 :piWGINTS.unii).

java.lang.NullPointerException
at java.lang.Throwable.<init>(Throwable.java:181)
at java.lang.RuntimeException.<init>(RuntimeException.java:32)
at java.lang.NullPointerException.<init>(NullPointerException.java:36)
at com.mysql.jdbc.PreparedStatement.set(Unknown Source)
at com.mysql.jdbc.PreparedStatement.setLong(Unknown Source)


The RPG error (joblog) shows this:
Message ID . . . . . . : RNX0301 Severity . . . . . . . : 50
Message type . . . . . : Escape
Date sent . . . . . . : 09/08/10 Time sent . . . . . . :
11:16:58

Message . . . . : Java exception received when calling Java method.
Cause . . . . . : RPG procedure JDBC_SETLO in program SVCPGM/JDBCR4
received
Java exception "java.lang.NullPointerException:" when calling method
"setLong" with signature "(IJ)V" in class "java.sql.PreparedStatement".
Recovery . . . : Contact the person responsible for program maintenance
to
determine the cause of the problem.
Technical description . . . . . . . . : If the exception indicates that
the
Java class was not found, ensure the class for the method is in the class
path. If the exception indicates that the Java method was not found,
check
the method name and signature. If the signature is not correct, change
the
RPG prototype for the method, or change the Java method, so that the
return
type and parameter types match. You can determine the signatures for all
the


"Scott Klement" <rpg400-l@xxxxxxxxxxxxxxxx> wrote in message
news:mailman.6320.1283960007.2619.rpg400-l@xxxxxxxxxxxxxxx

I don't agree with your assessment.

It closes the current statement -- i.e. it releases the database
resources it's currently using, so the database manager will stop
processing the SQL statement that you executed, and free up it's memory.

It doesn't free the PreparedStatement object you created! It doesn't
prevent you from inserting new parameter markers and running it again! It
just closes the previous run so you aren't running BOTH.


On 9/8/2010 9:51 AM, hockchai Lim wrote:

I just did some studying on Scott Klement's JDBC_FreeResult export
procedure. In observing the code, it seems like this procedure not only
closes and frees the ResultSet, it also auto closes and frees the
PreparedStatement object that is associated to the ResultSet.

I've wrote a RPG program that needs to a same PreparedStatment object to
perform different queries using different parameter mark values. So, I
really do not want to free the PreparedStatement object when freeing the
ResultSet. Does anyone know of the best way to handle this?

Thanks