SqlException Class
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SqlException Class

 

The exception that is thrown when SQL Server returns a warning or error. This class cannot be inherited.

Namespace:   System.Data.SqlClient
Assembly:  System.Data (in System.Data.dll)

System.Object
  System.Exception
    System.SystemException
      System.Runtime.InteropServices.ExternalException
        System.Data.Common.DbException
          System.Data.SqlClient.SqlException

[SerializableAttribute]
public sealed class SqlException : DbException

NameDescription
System_CAPS_pubpropertyClass

Gets the severity level of the error returned from the .NET Framework Data Provider for SQL Server.

System_CAPS_pubpropertyClientConnectionId

Represents the client connection ID. For more information, see Data Tracing in ADO.NET.

System_CAPS_pubpropertyData

Gets a collection of key/value pairs that provide additional user-defined information about the exception.(Inherited from Exception.)

System_CAPS_pubpropertyErrorCode

Gets the HRESULT of the error.(Inherited from ExternalException.)

System_CAPS_pubpropertyErrors

Gets a collection of one or more SqlError objects that give detailed information about exceptions generated by the .NET Framework Data Provider for SQL Server.

System_CAPS_pubpropertyHelpLink

Gets or sets a link to the help file associated with this exception.(Inherited from Exception.)

System_CAPS_pubpropertyHResult

Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.(Inherited from Exception.)

System_CAPS_pubpropertyInnerException

Gets the Exception instance that caused the current exception.(Inherited from Exception.)

System_CAPS_pubpropertyLineNumber

Gets the line number within the Transact-SQL command batch or stored procedure that generated the error.

System_CAPS_pubpropertyMessage

Gets a message that describes the current exception.(Inherited from Exception.)

System_CAPS_pubpropertyNumber

Gets a number that identifies the type of error.

System_CAPS_pubpropertyProcedure

Gets the name of the stored procedure or remote procedure call (RPC) that generated the error.

System_CAPS_pubpropertyServer

Gets the name of the computer that is running an instance of SQL Server that generated the error.

System_CAPS_pubpropertySource

Gets the name of the provider that generated the error.(Overrides Exception.Source.)

System_CAPS_pubpropertyStackTrace

Gets a string representation of the immediate frames on the call stack.(Inherited from Exception.)

System_CAPS_pubpropertyState

Gets a numeric error code from SQL Server that represents an error, warning or "no data found" message. For more information about how to decode these values, see SQL Server Books Online.

System_CAPS_pubpropertyTargetSite

Gets the method that throws the current exception.(Inherited from Exception.)

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetBaseException()

When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.(Inherited from Exception.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetObjectData(SerializationInfo, StreamingContext)

Sets the SerializationInfo with information about the exception.(Overrides Exception.GetObjectData(SerializationInfo, StreamingContext).)

System_CAPS_pubmethodGetType()

Gets the runtime type of the current instance.(Inherited from Exception.)

System_CAPS_pubmethodToString()

Returns a string that represents the current SqlException object, and includes the client connection ID (for more information, see ClientConnectionId).(Overrides ExternalException.ToString().)

This class is created whenever the .NET Framework Data Provider for SQL Server encounters an error generated from the server. (Client side errors are thrown as standard common language runtime exceptions.) SqlException always contains at least one instance of SqlError.

Messages that have a severity level of 10 or less are informational and indicate problems caused by mistakes in information that a user has entered. Severity levels from 11 through 16 are generated by the user, and can be corrected by the user. Severity levels from 17 through 25 indicate software or hardware errors. When a level 17, 18, or 19 error occurs, you can continue working, although you might not be able to execute a particular statement.

The SqlConnection remains open when the severity level is 19 or less. When the severity level is 20 or greater, the server ordinarily closes the SqlConnection. However, the user can reopen the connection and continue. In both cases, a SqlException is generated by the method executing the command.

For information about the warning and informational messages sent by SQL Server, see the Troubleshooting section of SQL Server Books Online. The SqlException class maps to SQL Server severity.

The following is general information on handling exceptions. Your code should catch exceptions to prevent the application from crashing and to allow displaying a relevant error message to the user. You can use database transactions to ensure that the data is consistent regardless of what happens in the client application (including a crash). Features like System.Transaction.TransactionScope or the BeginTransaction method (in System.Data.OleDb.OleDbConnection, System.Data.ODBC.ODBCConnection, and System.Data.SqlClient.SqlConnection) ensure consistent data regardless of exceptions raised by a provider. Transactions can fail, so catch failures and retry the transaction.

Note that beginning with .NET Framework 4.5, SqlException can return an inner Win32Exception.

The exception class of a .Net Framework data provider reports provider-specific errors. For example System.Data.Odbc has OdbcException, System.Data.OleDb has OleDbException, and System.Data.SqlClient has SqlException. For the best level of error detail, catch these exceptions and use the members of these exception classes to get details of the error.

In addition to the provider-specific errors, .NET Framework data provider types can raise .NET Framework exceptions such as System.OutOfMemoryException and System.Threading.ThreadAbortException. Recovery from these exceptions may not be possible.

Bad input can cause a .NET Framework data provider type to raise an exception such as System.ArgumentException or System.IndexOutOfRangeException. Calling a method at the wrong time can raise System.InvalidOperationException.

So, in general, write an exception handler that catches any provider specific exceptions as well as exceptions from the common language runtime. These can be layered as follows:

Try {
   // code here
}
catch (SqlException odbcEx) {
   // Handle more specific SqlException exception here.
}
catch (Exception ex) {
   // Handle generic ones here.
}

Or:

Try {
   // code here
}
catch (Exception ex) {
   if (ex is SqlException) {
      // Handle more specific SqlException exception here.
   }
   Else {
      // Handle generic ones here.
   }
}

It is also possible for a .NET Framework data provider method call to fail on a thread pool thread with no user code on the stack. In this case, and when using asynchronous method calls, you must register the UnhandledException event to handle those exceptions and avoid application crash.

The following example generates a SqlException and then displays the exception.

public static void ShowSqlException(string connectionString)
{
    string queryString = "EXECUTE NonExistantStoredProcedure";
    StringBuilder errorMessages = new StringBuilder();

    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        SqlCommand command = new SqlCommand(queryString, connection);
        try
        {
            command.Connection.Open();
            command.ExecuteNonQuery();
        }
        catch (SqlException ex)
        {
            for (int i = 0; i < ex.Errors.Count; i++)
            {
                errorMessages.Append("Index #" + i + "\n" +
                    "Message: " + ex.Errors[i].Message + "\n" +
                    "LineNumber: " + ex.Errors[i].LineNumber + "\n" +
                    "Source: " + ex.Errors[i].Source + "\n" +
                    "Procedure: " + ex.Errors[i].Procedure + "\n");
            }
            Console.WriteLine(errorMessages.ToString());
        }
    }
}

Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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