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JDBC & Prepared Statements

Posted on 2004-10-14
14
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Last Modified: 2010-03-31
Hi there,

I have a strange problem ..iam unable to figure it out any help will be highly appreciated..I have a database with around 80 tables Iam doing something like

main()
{ PreparedStatement pStmt = null;
try
{
Connection conn = DatabaseConnectionPoolMgr.getConnection();
deleteTablesInternal(conn);
deleteSomeTables(conn);
String sSql = "Delete from demo where demoid=10";
pSmt = conn.prepareStatement(sSql);
pStmt.execute();
pStmt.Close();
System.out.println("After deleting from demo");
}
catch(Exception e)
{
e.printStackTrace();
throw e;
}
finally
{
if(conn!= null)
  conn.close();
if(pStmt != null)
  pStmt.close();
}

}
In deleteTablesInternal() iam deleting some tables using preparedStatement & in deleteSomeTables() also, iam doing the same thing, finally iam deleting from the demo table which is the last table... My problem is the statement "After deleting from demo " is being displayed but the data is not deleted from demo table, all other tables are working fine...Iam using oracle9i as the database, iam in a dilemma & unable to figur it out whether its a database problem or jdbc problem. Any help wil be highly appreciated. thanxs in advance.

*Satish
0
Comment
Question by:satishAnanthuni
14 Comments
 
LVL 37

Accepted Solution

by:
zzynx earned 125 total points
ID: 12316472
Sure you have entries for which demoid=10?
0
 
LVL 92

Expert Comment

by:objects
ID: 12316477
check that rows exist with demoid=10
the return value from an update will tell you how many rows were affected.
0
 
LVL 37

Expert Comment

by:zzynx
ID: 12316480
You could try executeUpdate() instead of execute()
0
 
LVL 37

Expert Comment

by:zzynx
ID: 12316483
>>the return value from an update will tell you how many rows were affected.
If you use executeUpdate()
0
 
LVL 14

Expert Comment

by:Tommy Braas
ID: 12321606
Hi satishAnanthuni,

There is no need to use a PreparedStatement in this case, not that it should matter.

Try this:
Statement pStmt = null;
try
{
Connection conn = DatabaseConnectionPoolMgr.getConnection();
deleteTablesInternal(conn);
deleteSomeTables(conn);
String sSql = "Delete from demo where demoid=10";
pSmt = conn.createStatement();
pStmt.executeUpdate(sSql);
pStmt.Close();
System.out.println("After deleting from demo");
}


Cheers!

\tt
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Author Comment

by:satishAnanthuni
ID: 12336349
Hi All,

Its still confusing, there is one record in the demo table with demoid = 10 & the executeUpdate() returns me 1 but somehow, the record still exists in the database..


*Satish
0
 
LVL 92

Assisted Solution

by:objects
objects earned 125 total points
ID: 12336358
If its returning 1 then it is deleting it.
Are you sure you're not inserting it again later, or checking the wrong database/table?
0
 
LVL 37

Expert Comment

by:zzynx
ID: 12336554
>> executeUpdate() returns me 1 but somehow, the record still exists in the database
Rather impossible.
>> Are you sure you're not inserting it again later, or checking the wrong database/table?
Better double check that
0
 
LVL 92

Expert Comment

by:objects
ID: 12336581
zzynx,

really no need to repeat everything I said.
0
 

Expert Comment

by:rickychow
ID: 12345124
i found that u haven't commit, did u do the commit?

conn.setAutoCommit(false);
deleteTablesInternal(conn);
deleteSomeTables(conn);
String sSql = "Delete from demo where demoid=10";
pSmt = conn.prepareStatement(sSql);
pStmt.execute();
pStmt.Close();
System.out.println("After deleting from demo");

conn.commit();
0
 
LVL 37

Expert Comment

by:zzynx
ID: 12544842
Proposal: split objects - zzynx
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