How to catch expections related only to connection problem

Question

1.00/5 (2 votes)

See more:

Hi All,

I have searched a lot on this topic. But all in vain.

Kindly advice me, how to catch exceptions which are related to connection lost(both SQL and Oracle) problem.

Thanks in advance.

Posted 15-Oct-14 5:14am

furynight8

Updated 15-Oct-14 23:07pm

v2

Add a Solution

Comments

ZurdoDev 15-Oct-14 11:15am

Where are you stuck? You can catch Exception or you can catch SqlException, etc.

PIEBALDconsult 15-Oct-14 11:38am

If you mean, only when trying to create/open the connection then, put only those statements (and nothing else) in a try/catch

Maciej Los 15-Oct-14 15:47pm

What you mean? Is there any reason to catch only exceptions related to the "connection"?

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

NaibedyaKar · Answer 1 · 2014-10-15T05:37:00

Solution 1

You can handle specific exceptions like this.

C#

Try {
   // code here
}
catch (SqlException odbcEx) {
   // Handle SQL related excetion here, you can catch more specific exception inside this.
}

 catch (OracleException e)
    // Handle Oracle related exceptions
   {

catch (Exception ex) {
   // Handle generic exceptions here
}

Posted 15-Oct-14 5:37am

NaibedyaKar

Comments

Sergey Alexandrovich Kryukov 15-Oct-14 12:18pm

It would be good, but bad part is catching System.Exception. You create a false impression that all exceptions should be caught. Wrong. Exceptions are structured. Just remove this part; and other exceptions will be propagated up the stack, the be handled somewhere on top (eventually, all of them should be caught). Catching too locally is a big fallacy.
—SA

furynight8 16-Oct-14 3:53am

Hi All,

First of all, thanks a lot for all your replies.

I am having the below code in my application, to catch row level exceptions.

OracleCommand actionRtfCommand = new OracleCommand("select * from ACTION_RTF", conn);
actionRtfCommand.InitialLONGFetchSize = -1;
OracleDataReader actionRtfReader = actionRtfCommand.ExecuteReader();

// read only one record each roundtrip to avoid that exception has consequences for subsequent read statements
// (when the exception occurs the buffer becomes corrupted giving problems for subsequent read operations to the same buffer)
// Since this reduction of fetchsize (increasing number of roundtrips) has a significant performance penalty (typical fetchsize is 131072)
// it should only be applied when command involves LONG or LONG RAW columns
actionRtfReader.FetchSize = actionRtfReader.RowSize;

bool endOfFile = !actionRtfReader.HasRows;
while (!endOfFile)
{
try
{
bool readResult = actionRtfReader.Read();
endOfFile = !readResult;
}
catch (Exception rowLevelException)
{
// handle exception
MessageBox.Show(rowLevelException.GetType().ToString() + " : " + rowLevelException.Message);
}
}

DataReader will fetch only one row at a time and if any exceptions occurs while reading it will be caught in the exception.

Sometimes while executing the loop, the connection to the database is lost due to some reason. So only in condition when the connection to the database is lost, i have to terminate the program. In other conditions, it should work as it is working now.

NaibedyaKar 16-Oct-14 3:58am

Why don't you add one condition there to check the database connection before doing any task.

furynight8 16-Oct-14 4:11am

Hi,

I am checking the connection while saving the details in DataReader. I have millions of records to be fetched from database. Since DataReader is a connected object, I am getting exception in each objDataReader.Read() statement. For example, say i have fetched around 5000 rows from database using the Read() statement and the connection to database is lost while fetching 5001 row.

There may be many exceptions while objDatareader.Read(), but only when the exception occurs due to connection lost, i have to terminate my program.

Kindly advice me how to proceed in this.

furynight8 16-Oct-14 5:13am

I have tried to solve my problem by below approach.

bool endOfFile = !actionRtfReader.HasRows;
while (!endOfFile)
{
try
{
bool readResult = actionRtfReader.Read();
endOfFile = !readResult;
}
catch (Exception rowLevelException)
{
if (ex.Message.ToString().ToLower().Contains("connect"))
{
Environment.Exit(0);
}
else
{
MessageBox.Show(rowLevelException.GetType().ToString() + " : " + rowLevelException.Message);
}
}
}

I am checking whether the exception message contains "connect". If it contains "connect" , i am terminating my program.

Kindly advise me whether my approach is correct.

NaibedyaKar 16-Oct-14 5:24am

Well, I think it is some work around, but might not be the best approach.
Can we not use disconnected architecture or something so that we will have all the data in place and no way we have the exceptions. Not sure if it is really a valid.

furynight8 · Answer 2 · 2014-10-15T23:15:00

Hi All,

I have tried to solve my problem by below approach.

bool endOfFile = !actionRtfReader.HasRows;
while (!endOfFile)
{
try
{
bool readResult = actionRtfReader.Read();
endOfFile = !readResult;
}
catch (Exception rowLevelException)
{
if (ex.Message.ToString().ToLower().Contains("connect"))
{
Environment.Exit(0);
}
else
{
MessageBox.Show(rowLevelException.GetType().ToString() + " : " + rowLevelException.Message);
}
}
}

I am checking whether the exception message contains "connect". If it contains "connect" , i am terminating my program.

Kindly advise me whether my approach is correct.