Printing queries in prepared statement

I have a created a prepared statement. When I execute the query I get an error stating that the SQL isn't correct. I would therefore like to print out the statement so I can see what it looks like. Here is what my code is doing.
Create a query string with question marks.
Hand that string off to the preparedStatement constructor.
Modify that string using setString() One for every question mark.
Send the query off by calling executeQuery()
All I want to do is print out what the statement now looks like after the setStrings() are called.
Thanks,
-KAP

That's not a featured guaranteed by the JDBC specification, and because of the way PreparedStatement really works, it can't be.
You see, PreparedStatement usually does not do string replacement into your SQL; the SQL passed to the database still has the ?s in it and the values are bound later, in the database, to a compiled object that is no longer text.
A few drivers will give you back the SQL statement if you apply toString() on the PreparedStatement, and maybe even given you the current values of the bind variables, but most won't.
In fact, normally when you get have invalid SQL with a PreparedStatement, the SQLException is thrown on the prepareStatement method, before the set methods are called; if they're not, then you're probably trying to do an invalid implicit data type conversion. In other words, at least some of the columns in your database are not of character type, and the database is trying to convert your strings to the other type (using its rules, which may be different from Java's rules and may be different from another database's rules), and failing.

Similar Messages

Running explain plan on a prepared statement

I'm using IBatis to run queries against an Oracle database. IBatis runs the queries as prepared statements. I want to run explain plan on the prepared statements.
I already have a shim -- a proxy java.sql.Connection object -- that takes the SQL used to create a prepared statement (e.g., "select a, b, c from table d where c = ?"), returns a proxy java.sql.PreparedStatement, and then on the PreparedStatement's execute(), interpolates the bound parameters into the SQL statement, and runs Explain Plan on that (e.g, preparedStatement.setInt(5) is called, followed by preparedStatement.execute(), which results in my proxy running "explain plan for select a, b, c from table d where c = 5;")
Using Spring configuration, I can transparently insert the shim and get explain plans for all queries run through that Connection.
The problem is this: I'm explaining the plan for the SQL with the bound parameters, not necessarily the SQL run for the prepared statement.
Assume that in the above example, there exists an index on column c in table d, and that 5% of d's rows have the value 1, 15% have the value 2, and 80% have the value 3.
For "select a, b, c from table d where c = 1", Oracle will use the index. But for "select a, b, c from table d where c = 3", Oracle will do a full table scan.
What I want to know is what Oracle will do for "select a, b, c from table d where c = ?" when "?" is an unknown, arbitrary value subsequently bound to 1 or to 3.
As I understand it, the query plan for a prepared statement is done once, when the prepared statement is created. At execute time (as I understand it), the query plan is not reformulated based on the actual bound values (though partition pruning is recalculated).
So how can I find out what query plan is actually be used for prepred statement?
Thanks.

I already have a shim -- a proxy java.sql.Connection object -- that takes the SQL used to create a prepared statement I believe explain plan is part of PL/SQL rather than external to it.
As such you can pass it via a prepared statement. It is just a matter of getting the syntax correct. And of course collecting the result.
The syntax is going to be be something like the following. You would use it just like you use the existing sql.
begin
select ... from ... where c = ?;
endThe result might be returned a result sets (plural). If so you would need to code appropriately for that.

? in SQL Queries and not using prepared statements

Using EclipseLink 1.1.1
Prepared Statements are disabled
In our production server something went wrong and one of our Read Queries started erroring. A DatabaseException was thrown and we log the "getQuery.getSQLString()" statement. We found this query in the logs:
SELECT t1.ID, t1.NAME, t1.DESCRIPTION, t1.EXTREFID, t1.STYLESHEET, t1.DDSVNVERSION, t1.FIRSTNAME, t1.LASTNAME, t1.EMAILADDR, t1.PHONENUMBER, t1.ADDRESS, t1.ADDRESS2, t1.CITY, t1.STATE, t1.POSTALCODE, t1.COUNTRY, t1.ADMINACCTNAME, t1.HASDOCUMENTS, t1.HASTIMEDNOTIFICATIONS, t1.STATUS, t1.ENTRYDATE, t1.EVALEXPDATE, t1.LASTREMINDDATE, t1.FULLUSERS, t1.LIMUSERS, t1.REQUSERS, t1.ISENTERPRISE, t1.EXPDATE, t1.ISDISABLED, t1.DISABLEDDATE, t1.NEEDLICENSEAGREEMENT, t1.ISWARNINGDISABLED, t1.LOCALE, t1.TIMEZONE, t1.CURRENCY, t1.DOMAIN, t1.DOCUMENTSIZE, t1.EXTRADOCUMENTSTORAGE, t1.ONDEMANDOPTIONS, t1.SSOTYPE, t1.RESELLERID, t1.ACCOUNTREPID, t1.LASTUSAGEREPORTDATE, t1.NEXTUSAGEREPORTDATE, t1.USAGEREPORTATTEMPTS FROM T_SSOOPTIONS t0, T_CUSTOMERS t1 WHERE *((((t0.SSOENABLED = ?) AND (t1.SSOTYPE IN (?, ?))) AND (UPPER(t1.DOMAIN) = ?)) AND (t0.CUSTOMERID = t1.ID))*
Notice the values weren't entered into the where clause. We had to bounce the application to fix the problem. I've never seen this before. I've added more debugging statements to the code - so if this happens again in the future I'll have more information to report on. In the mean time I'm wondering if anyone else has every seen a problem of this nature.

Database error due to invalid SQL statement.
I don't have a stack, we were catching the exception and not printing the stack :(
Like I mentioned in my first post, I added more debugging code (e.printStackTrace()). I understand this is hard to track down without more information. I was just hoping you guys had seen something like this before and had any insight. Like I mentioned before: this is on our production server. I've never seen this type of error before. That particular server (we run in a cluster mode) had been up for several days and then started generating that error. IT bounced the node and everything went back to normal. We have been using toplink for about 5 years now and have never seen this problem, until August 3rd 2009. The only thing that has changed recently is our migration from toplink 10 to EclipseLink. I was wondering if anyone knows if anything had changed in EclipseLink/toplink 11 with the generation of SQL queries.
I'll keep looking. There is more debugging code in there now. Since the error was "Database error due to invalid SQL statement" this implies the SQL was generated, exited that part of the code and was sent to the db where it failed. I'm afraid the printStackTrace won't help if this error happens again.

Printing Prepared Statement Query

Hi all,
Is it possible to print Prepared Statement query. When i give System.out.println(query);, i get the query with '?' and not with the actual value sent. How can i print the query with the value passed in place of the '?' ?

Hi all,
Is it possible to print Prepared Statement
tatement query. When i give
System.out.println(query);, i get the query with '?'
and not with the actual value sent. How can i print
the query with the value passed in place of the '?' ?The simple answer is that you can't (AFAIK), but some database drivers are able to log the sql statements.
Kaj

When to use prepared statement in java?

Hi all,
If we have query like select * from {tablename} (Here tablename is the variable) then will the use of prepared staement improve the performance? My guess is use of statement in this case is a better option rather than prepared statement as the tablename may change for every other query.I think are not useful if tablename changes.They are useful only when the where clause has dynamic values.

cantor wrote:
Are you sure that your approach is possible? The next example causes exception for me.
PreparedStatement ps = conn.prepareStatement("select * from ?");
ps.setString(1, "TABLE_NAME");
ps.executeQuery();
I didn't say that he should solve it in that way. He should create one prepared statement like this "select a, b, c from tablename1" and another prepared statement when he wants to execute "select d, e, f from tablename2"
>
And as I understand, this code will not improve perfomance (and even will not work). As I said it can.
Prepared statements make possible usage compiled queries inside DB. When DB gets prepared statement call, it need to parse it only once. And it can collect some statistic to improve execution plan. But when table name is not specified, this approach will not work.Yes it might. There are database drivers that can cache prepared statements and it's isn't likely that he executes that query on more than e.g. 20 tables?
The database can also cache compiled statements in a cache.
Kaj

Required Prepared Statement help

Consider the following query
select col2, col3
from table1
where col1 = ?
I can set the bindings for the prepared statement as pStmt.setString(1, value);
but sometimes I need all the rows in the table therefore the query would be like
select col2, col3
from table1
where col1 = col1
I would like to set the first query's bindings for the prepared statement to execute like the second one.
Please do not ask me to create two different queries. I know it is possible to do it and I would appreciate if you can guide me as to how to set the bindings. Thanks,

Adam Martin wrote:
Sorry, you cannot treat a bind variable like a bind some of the time and literal SQL text the other part of the time.
How about something like this:
select col2, col3
from table1
where col1 between ? and ?When you want a specific value, you can say "between 23 and 23" and when you want all values, you can put extremes in like "between -999999 and 999999" so that all rows a returned.
This is not to say that this is a great approach, but it seems like it would technically allow you to do what you wanted.This is an EXCELLENT approach to confuse the optimizer & produce poor performance.
I suspect that using the same EXPLAIN PLAN to bring back 1 or and bring back all rows;
will be suboptimal for a subset of all executions.

Disadvantages in prepared statement

hi
i could not tell the answer for the following question in my interview can u pleae tell me the answer for this question
one of the disadvantages with prepared statement in jdbc?

I have no idea what WorkForFood is talking about.Sorry, perhaps an example will help clarify:
Using a PreparedStatement using two replacement parameters:
String sql = "SELECT COL1 FROM MYTABLE WHERE COL1 = ? AND COL2 = ?";
ps.setSetring("WORK");
ps.setString("FORFOOD");Contrasted against a Statement using literals:
"SELECT COL1 FROM MYTABLE WHERE COL1 = 'WORK' AND COL2 = 'FORFOOD'";When you execute these two queries, they can generate different explain plans, for example the Statement may use an index while the PreparedStatement may attempt a full table scan. The optimizer is choosing a more efficient explain plan for the Statement because it has more information on which to make a decision (the literal values). A full table scan will be significantly slower then using an index to return the same results. In some databases, you can provide hints, but in some cases, the only way to get this query to use an index is to provide the actual values WORK and FORFOOD in the query itself. When using literals rather then replacement parameters it should be more efficient to use Statement then PreparedStatement (see jschell's list #1). So, in these cases, you should use a Statement rather then a PreparedStatement to get best performance from your query. And again, this issue comes up very infrequently but can be quite debilitating to an applications performance when it does occur.

Prepared Statement with SQL 'IN' Clause

Hi,
I am trying to write a JDBC SQL call to a database using a prepared statement, the call looks something like:
select *
from table
where field in (?, ? ,?)
this thing is that i don't know how many 'IN' parameters are needed until runtime (they come from a List), so is there an easy way of dealing with this, I haven't been able to find any information on this problem anywhere?

>
Hmmm...more expensive than say doing a query on on 2 billion rows with no index?
More expensive than doing a cross server join?
More expensive than doing a restore?
I knew that someone would point this out. :)
I just tried to exaggerate the importance of cursor sharing. This is one of the most important topic in DBMS world, but quite often ignored by JAVA world. I hope that you understand my good intention.
>
2. Insert data corresponding to bind variable to "T". Interesting idea. Please provide the algorithm for that. The only ones I can come up with
1. Involved creating a "dynamic" SQL for the insert
2. Doing multiple cross network inserts.
The first of course is exactly what you said your solution prevented. The second will be more expensive than sending a single dynamically created select.Hopefully, this is not just an "interesting" idea, but very common technique in DBMS. Actually one of the common techniques. There are couple of ways to handle this kind(variable number of bind variables in "IN" clause) of problem.
What i commented was that the simplest one. It's like this:
(based on Oracle)
SQL> create global temporary table bind_temp(value int);
PreparedStatement stmt = con.prepareStatement("INSERT INTO bid_temp VALUES(?)");
for(...) {
stmt.setInt(1, aValue)
stmt.addBatch();
stmt.executeBatch();
Statement stmt2 = con.executeQuery("SELECT * FROM target_table WHERE id IN (bind_temp)");
...Doesn't it look pretty? Pretty for both Java developers and DBAs.
By virtue of the mechanism of batch processing, the total DBMS call is just twice and you need just 2 completely sharable SQL statements.
(Hopefully you might understand that Oracle global temporary table is just session scope and we don't need them to be stored permanently)
Above pattern is quite beneficial than these pattern of queries.
SELECT * FROM target_table WHERE id IN (?)
SELECT * FROM target_table WHERE id IN (?,?)
SELECT * FROM target_table WHERE id IN (?,?,?)
SELECT * FROM target_table WHERE id IN (?,?,?,?,.......,?)
If you have large quantity of above patterns of queries, you should note that there are another bunch of better techniques. I noted just one of them.
Hope this clairfies my point.

What is a better approach, batch or prepared statement?

Hi,
In my application, the user account property will be retrieved from DB and the last login time will be updated after a successful sign on. There are two query statements in this procedure; select and update. What is a better approach in JDBC to deal with the two queries: batch or prepared statement?
Thanks.

Hi, Duffy,
Thanks for your input.
I would like to use PreparedStatement with batch update. From my reading, however, it is not suitable to use PreparedStatement with batch update. At less, I haven't see a single example on the tutorial or article sections of this site. I am not sure the following is valid or not:
               stmt = connection.prepareStatement(INSERT_SMT_QUERY_STR);
               stmt.setLong(1, details.getRegardID());
               stmt.setLong(2, details.getWriterID());
               stmt.setInt(3, details.getVisibility());
               stmt.setString(4, details.getSubject().trim());
               stmt.setString(5, details.getContent().trim());
stmt.addBatch() <-- what goes into here?

Prepared Statement and Stored Procedure difference?

For SQL in my web applications I use PreparedStatement object alot in my JDBC working with Oracle 9i.
I also heard the term Stored Procedure. What is the difference between Stored Procedure and Prepared Statement?

I am new to java programming, can anybody explain
what exactly precompiled means
Thank you
PalspaceWhat does you subject line have to do with your question?
The difference between a stored proc and a prepared statement is mainly this.
A stored proc is stored in the database server permanently and can be used and re-used from a different connections.
A PreparedStatement is not valid across connections.
Stored procs are almost always precompiled. (I am just hedging a bit here just in case but you can consider it 100%)
PreparedStatements MAY be precompiled. Hard to say.
Precompiling means at least one of and perhaps all of the following depending on the database
- The parsing of the SQL statement
- The checking of the SQL against the data dictionary to ensure that the tables and columns referenced actually exist
- The preparation of a query plan
Last but not least Stored procedures may (and often do) contain more than simple queries but are in fact relatively complex programs written in a DB specific language (an offshoot of SQL of some sort).

Query slow when executing using prepared statement compared to sqlDeveloper

Oracle version is 10.2.0.1.0.
I have got a query which when submitted from java code using prepared statement and parameter substitutions, takes more than 20 seconds to give results.
I can see this SELECT sql sitting there when I run Monitor Sessions through sqlDeveloper, with its wait time increasing and then finally getting through. During that time no other SQLs are waiting.
DURING THAT TIME then I am able to run the same query (with values included) multiple times using sqlDeveloper, and it gives results in no time.
Sqldeveloper connects using thin client using lib provided by oracle in windows.
Java code runs from linux and uses the thin client using lib provided by oracle in linux.
Both are hitting the same DB running on a separate Linux machine.
What could be the cause of this problem?
What db parameters, queries should I run to identify the bottleneck?
Edited by: user10390517 on Jun 14, 2010 3:06 AM

Hi Rob,
at least you should see some differences in the statistics for the different child cursor (the one for the execution in the application should show at least a higher value for ELAPSED_TIME). I would use something like the following query to check the information for the child cursors:
select sql_id
     , PLAN_HASH_VALUE
     , CHILD_NUMBER
     , EXECUTIONS
     , ELAPSED_TIME
     , USER_IO_WAIT_TIME
     , CONCURRENCY_WAIT_TIME
     , DISK_READS
     , BUFFER_GETS
     , ROWS_PROCESSED
from v$sql
where sql_id = your_sql_idRegards
Martin

Best Practice: Combine prepared statements with ;

Hi,
I would like to know what the best prctice is for combining prepared statements to give the query below
INSERT INTO my_table (value) VALUES (?); SELECT LAST_INSERT_ID()The reason for this is that i have written a simple DB wrapper to handle my database connections and queries based on a property file containing sql strings. I would prefer not to change this wrapper code, but be able to specify combined queries in the sql string if possible.
Thanks in advance

Have you thought about using Batch statements ?

JDBC: Prepared statements with more parameters than column names

I'm using the latest version of the JDBC driver - 4.1.5605.100_enu - on Java 1.7, Linux.
I'm connecting to MS SQL Server 2012 Express Edition using a connection URL of the form jdbc:sqlserver://10.0.0.2;user=username;password=pwd;database=testdb1
I have a table with two columns. One is an ID (type bigint) and one is numeric(38, 19).
The following code works exactly as expected:
PreparedStatement stm = connection.prepareStatement("INSERT INTO myTable(id, num) VALUES (?, ?)")
// repeatedly set parameters using setLong, setBigDecimal, then addBatch
stm.executeBatch()
The following code does not work as expected:
PreparedStatement stm = connection.prepareStatement("INSERT INTO myTable(id, num) VALUES (?, ?), (?, ?)");
stm.setLong(1, 1);
stm.setBigDecimal(2, new BigDecimal("1.234"));
stm.setLong(3, 2);
stm.setBigDecimal(4, new BigDecimal("1.234"));
stm.addBatch();
stm.executeBatch();
The code runs normally in the second case, but the second row inserted contains the wrong value in the "num" column - it's been rounded to 1.0 instead of stored as 1.234.
I think this may be because the driver does not understand the types of parameters whose indexes are beyond the number of columns in the insert statement. Running the following code on the second prepared statement:
System.err.println(stm.getParameterMetaData().getParameterTypeName(2)); // prints "numeric"
System.err.println(stm.getParameterMetaData().getParameterTypeName(4)); // fails with IndexOutOfBoundsException
As far as I can tell from the JDBC JavaDoc, this usage is valid and ought to work. Certainly it works as expected (including the parameter metadata) using PostgreSQL and their JDBC driver. Is this a bug in Microsoft's driver?

Hi dtn-cfl,
Thanks for your waiting.
Based on my research(using
SQL Server Profiler to trace DB events), the preparedStatement finally passes the below statements to SQL Server.
stm.setLong(1, 1);
stm.setBigDecimal(2, new BigDecimal("1.234"));
stm.setLong(3, 2);
stm.setNull(4, Types.DECIMAL);
declare @p1 int
set @p1=0
exec sp_prepexec @p1 output,N'@P0 bigint,@P1 decimal(38,3),@P2 bigint,@P3 decimal(38,0)',N'INSERT INTO myTable(id, num) VALUES (@P0, @P1), (@P2, @P3) ',1,1.234,2,NULL
select @p1
Pay attention to the @P3 decimal(38,0), it seems(I don't have access to JDBC source code so that I have to use seem) that the
stm.setNull(4, Types.DECIMAL) will finally parsed as a type decimal(38,0). In SQL Server, to a
decimal datatype，one with smaller scale has a higher precedence. To understand the precedence， please see below code. If you have more interest in data type precedence, you can click
here.
declare @num1 decimal(38,3) --scale 3
declare @num2 decimal(38,2) --scale 2
set @num1 = 3.225
set @num2 = 3.22
select @num1 as num
union all
select @num2
output
num
3.23
3.22
@num1 get rounded to keep the column data type consistency, namely keep the column as type decimal(38,2)
Let's go back to your code, if you would like to make your code work properly, please see below.
stm.setLong(1, 1);
stm.setBigDecimal(2, new BigDecimal("1.234"));
stm.setLong(3, 2);
stm.setNull(4, Types.INTEGER);As per the above data type precedence link, a decimal has a higher precedence than integer, so your decimal will not get rounded.
Not only the case in your post, but also any data type inconsistency will lead to the rounding problem. See below.
stm.setLong(1, 1);
stm.setBigDecimal(2, new BigDecimal("1.234"));
stm.setLong(3, 2);
stm.setBigDecimal(4, new BigDecimal("1.2")); // or new BigDecimal("1.23") and any other decimal with different scale leads to rounding problem.
So when you set parameters for a prepareStatement like "INSERT INTO myTable(id, num) VALUES (?, ?), (?, ?)" with more than one row, you should pay attention to data type consistency fact.
The Microsoft JDBC driver for SQL Server may not be that intelligent, however we can't say that is a bug definitely.
If you have any question, feel free to let me know.
Eric Zhang
TechNet Community Support

Deployments are in Active state on Cluster but in Prepared state on server

Hi,
We initially deployed our application (Oracle Identity Manager 11gR2) on standalone managed server and then convert it into cluster using wlst commands.
readDomain('/app/oracle/Middleware_OAM/user_projects/domains/oim_domain')
setDistDestType('JRFWSAsyncJmsModule', 'UDD')
setDistDestType('OIMJMSModule', 'UDD')
create('oim_cluster','Cluster')
assign('Server','oim_server1','Cluster','oim_cluster')
updateDomain()
The cluster is created fine and we can start the application successfully and access it. However the problem is that all the deployments are in 'Active' state only under Cluster but in prepared state under the server oim_server1 (though application access working on managed server port). Please advise where we are missing and what could be the wrong?
Thanks

Hi,
1. What if you are trying to access the application page, does it come up ?
2. Use the below wlst command to get the actual state of the deployed application:
The deploy command returns a WLSTProgress object that you can access to check the status of the command. The WLSTProgress object is captured in a user-defined variable, in this case, progress.
wls:/mydomain/serverConfig/Servers> progress= deploy(appName='businessApp',path='c:/myapps/business',createplan='true')
The previous example stores the WLSTProgress object returned in a user-defined variable, in this case, progress. You can then use the progress variable to print the status of the deploy command. For example:
wls:/mydomain/serverConfig/Servers> progress.printStatus()
Current Status of your Deployment:
Deployment command type: deploy
Deployment State : completed
Deployment Message : null
wls:/mydomain/serverConfig/Servers>
3. Restart all the servers, instances, related DB and check if it helps.
Thanks,
Sharmela

Prepared Statement Flooding

Hi Friends,
Need your help to fix this prolonging problem in one of our applications. We observe that the following queries are declared as prepared statements but have dynamic value ROWID in each.
SELECT ROWID, C. * FROM Table1 C WHERE C.VENDORLOGINID = ? AND C.VENDORTYPE = ? AND (ROWID = _ ROWID100)
SELECT ROWID, C. * FROM Table2 C WHERE C.VENDORIDCH = ? AND (ROWID = _ ROWID114)
SELECT ROWID, C. * FROM Table1 C WHERE C.VENDORLOGINIDBASE = ? AND C.VENDORTYPE = ? AND (ROWID = _ ROWID58)
This results in a FLOOD of prepared statements (over 3000) as it is an application with a very large DB.
We found out that a newer version of Ojdbc14.jar (10.2.0.3.0) is available (At present we are shipping the product with 10.2.0.1.0). We tested with this newer jar and found out bind variables are not treated as dynamic variables with this jar file. SQL queries are getting cached as expected.
This new jar file did fix the problem when our DB was 10g for the application (another), but for this current application we are using Oracle 9i.
The same jar file does not seem to be fixing the issue.
Has anybody faced similar issue before?
Ideally the 10g jar file should eb backward compatible but for some reason it is not for this particular problem.
Please can somebody help to get a solution for this problem. Do let me know if you need more information.
Thanks.

Poornima wrote:
Is the prepared statement cache common to all the Connection objects in the Connection Pool or is there a separate cache for each statement in the Connection Pool?There is a separate statement cache for each connection in the pool.
Joe

Printing queries in prepared statement

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