C Sharp Database Error Handling
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C Sharp Database Connection Example
redirected in 1 second. MFC Desktop Applications Concepts Exception Handling Exception Handling Exceptions: Database Exceptions Exceptions: Database Exceptions Exceptions: Database
C Sharp Database Tutorial
Exceptions Exceptions: Changes to Exception Macros in Version 3.0 Exceptions: Catching and Deleting Exceptions Exceptions: Converting from MFC Exception Macros Exceptions: Using MFC Macros and C++ Exceptions Exceptions: Examining Exception Contents Exceptions:
C# Error Handling In Constructor
Freeing Objects in Exceptions Exceptions: Throwing Exceptions from Your Own Functions Exceptions: Exceptions in Constructors Exceptions: Database Exceptions Exceptions: OLE Exceptions TOC Collapse the table of content Expand the table of content This documentation is archived and is not being maintained. This documentation is archived and is not being maintained. Exceptions: Database Exceptions Visual Studio 2015 Other Versions Visual Studio 2013 Visual Studio 2012 Visual Studio c# error handling get line number 2010 Visual Studio 2008 Visual Studio 2005 Visual Studio .NET 2003 This article explains how to handle database exceptions. Most of the material in this article applies whether you are working with the MFC classes for Open Database Connectivity (ODBC) or the MFC classes for Data Access Objects (DAO). Material specific to one or the other model is explicitly marked. Topics include: Approaches to exception handlingA database exception-handling exampleApproaches to Exception HandlingThe approach is the same whether you are working with DAO or ODBC.You should always write exception handlers to handle exceptional conditions. The most pragmatic approach to catching database exceptions is to test your application with exception scenarios. Determine the likely exceptions that might occur for an operation in your code, and force the exception to occur. Then examine the trace output to see what exception is thrown, or examine the returned error information in the debugger. This lets you know which return codes you'll see for the exception scenarios you are using.Error Codes Used for ODBC ExceptionsIn addition to return codes defined by the framework, which have names of the form AFX_SQL_ERROR_XXX, some CDBExceptions are based on ODBC return codes. The return codes for
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring c# error handling framework developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask c# error handling techniques Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join c# error handling class them; it only takes a minute: Sign up try-catch every db connection? up vote 6 down vote favorite 1 Is it recommended to put a try-catch block in every function that opens a DB connection and log the error https://msdn.microsoft.com/en-us/library/19b8k939.aspx there, or should I rather catch errors in a higher layer of the application? public static Category GetCategoryByName(string name) { Category result; try { using (IDbConnection conn = ConnectionHelper.CreateDbConnectionByName(_connectionStringName)) { conn.Open(); using (IDbCommand cmd = conn.CreateCommand()) { //do stuff } } } catch(Exception e) { // log error here? } return result; } or rather try { Category myCat = DataTools.GetCategoryByName("myCat"); // other stuff } catch(Exception e) { // log error here? } To sum it up: Should errors http://stackoverflow.com/questions/4680845/try-catch-every-db-connection be caught as early as possible in the code? Or should I rather catch them where I have more information about the context? c# .net error-handling try-catch share|improve this question asked Jan 13 '11 at 14:00 atticae 5,28763890 add a comment| 4 Answers 4 active oldest votes up vote 12 down vote accepted As always, it depends, but in general, only catch an exception if you can do something about it, or you have specific code (e.g. a retry) to happen, otherwise, let the exception bubble up and the top most layer can log it/deal with it in a centralised fashion. Any other way results in a lot of logging code interspersed with all the business logic. share|improve this answer answered Jan 13 '11 at 14:02 Paddy 22.9k95691 add a comment| up vote 4 down vote When catching exceptions, always try to use the most accurate exception you can. For example, when using SQL Server, catch the SqlException as it will contain far more information about the exceptin than a generic Exception. You can get actual line numbers and other useful pieces of diagnostic information. After you have extracted and logged all that is relevent, rethrow the exception or wrap it in less specific exception such as an InvalidDataException or Exception and throw that. You can then catch these more generic exceptions at higher levels. try { // Execute DB call here } catch(SqlException exp)
Disconnected Data – The DataSet and SqlDataAdapter Lesson 06: Adding Parameters to Commands Lesson 07: Using Stored Procedures C# http://csharp-station.com/Tutorial/CSharp/Lesson15 Tutorial Lesson 1: Getting Started with C# Lesson 2: Operators, Types, http://csharp.net-informations.com/statements/csharp-exceptions.htm and Variables Lesson 3: Control Statements – Selection Lesson 4: Control Statements – Loops Lesson 5: Methods Lesson 6: Namespaces Lesson 7: Introduction to Classes Lesson 8: Class Inheritance Lesson 9: Polymorphism Lesson 10: Properties Lesson 11: Indexers Lesson 12: Structs Lesson 13: error handling Interfaces Lesson 14: Introduction to Delegates and Events Lesson 15: Introduction to Exception Handling Lesson 16: Using Attributes Lesson 17: Enums Lesson 18: Overloading Operators Lesson 19: Encapsulation Lesson 20: Introduction to Generic Collections Lesson 21: Anonymous Methods Lesson 22: Topics on C# Type Lesson 23: Working with Nullable Types LINQ Tutorial Lesson 01: c# error handling Introduction to LINQ Lesson 02: Forming Projections Articles Links ASP.NET Sites C# Sites .NET Sites Job Sites Object Oriented Sites Other Sites Tools VB.NET Sites Web Services Sites About Contact Link to C# Station Submit a site Support C# Station Terms of Service Lesson 15: Introduction to Exception Handling This lesson teaches how to handle exceptions in your C# programs. Our objectives are as follows: Learn what an exception is Implement a routine with a try/catch block Release resources in a finally block Exceptions Exceptions are unforeseen errors that happen in your programs. Most of the time, you can, and should, detect and handle program errors in your code. For example, validating user input, checking for null objects, and verifying the values returned from methods are what you expect, are all examples of good standard error handling that you should be doing all the time. However, there are times when you don't know if an error will occur. For ex
some conditions that changes the normal flow of execution . Exceptions are occurred in situations like your program run out of the memory , file does not exist in the given path , network connections are dropped etc. More specifically for better understanding , we can say it as Runtime Errors occurs during the execution of a program that disrupts the normal flow of instructions In .NET languages , Structured Exceptions handling is a fundamental part of Common Language Runtime . All exceptions in the Common Language Runtime are derived from a single base class , also you can create your own custom exception classes. You can create an exception class that inherits from Exception class . Creating an exception object and handing it to the runtime system is called throwing an exception. c# Exception Handling - try-catch C# Exception handling uses the try, catch, and finally keywords to attempt actions that may not succeed, to handle failures, and to clean up resources afterwards. try { //your code here } Catch (exception type) { //your code here }
finally The code in the finally block will execute even if there is no Exceptions. That means if you write a finally block , the code should execute after the execution of try block or catch block. try { //your code here } Catch (exception type) { //if the exception occurred //your code here } finally { //your code here } The following example trying to divide a number by zero. try { int val = 100; int div = 0; int resultVal; resultVal = (val / div); MessageBox.Show("The result is : " + resultVal); } catch (System.Exception ex) { MessageBox.Show("Exception catch here - details : " + ex.ToString()); } finally { MessageBox.Show("Enter finally block "); } How to throw Exception Exception objects that describe an error are created and then thrown with the throw keyword. By using a throw statement inside a catch block, we can change the resulting exception. More about.... throw exception How to create a custom exception If you want users to be able to programmatically distinguish between some error conditions, you should create your own custom exceptions. It will simplify and improve the error handling and thus increase the overall code quality. More about.... Create a custom exception System level Exceptions Vs Application level Exceptions Exceptions are provide a structured, uniform, and type-safe