Joseph Michael Pesch
VP Programming

SQL Server Identity Columns vs. Oracle Sequence Numbers

by 12. August 2008 21:28

In SQL server you create an identity column like the sample below which creates an identity column with seed value of 1 and increment value of 1.  Then when you insert records the column value is incremented and set automatically.

SQL Server Sample:
create table #MyTable(RecID int identity(1,1), MyData varchar(50))
insert into #MyTable(MyData) values('This is a test')
insert into #MyTable(MyData) values('This is another test')
select * from #MyTable
drop table #MyTable

Not so in Oracle.  There you create the integer column; however, you must manually increment and set the column value as part of your insert statement.  You can use a Sequence object (after you create one) as shown below.

create sequence MySequence minvalue 1 maxvalue 999999999999 start with 1 increment by 1 cache 20
create table imdw.MyTable(RecID int, MyData varchar2(50))
insert into imdw.MyTable(RecID, MyData) values(MySequence.nextval, 'This is a test')
insert into imdw.MyTable(RecID, MyData) values(MySequence.nextval, 'This is another test')
select * from imdw.MyTable
drop table imdw.MyTable
drop sequence MySequence

In both cases you should get the following result set:

 RecID MyData 
 1 This is a test 
 2 This is another test

Tags:

Oracle | SQL Server

SQL Server Split Function

by 12. August 2008 18:39

CREATE FUNCTION dbo.fnSplit(
    @sInputList VARCHAR(8000) -- List of delimited items
  , @sDelimiter VARCHAR(8000) = ',' -- delimiter that separates items
) RETURNS @List TABLE (recid int identity(1,1), item VARCHAR(8000))
BEGIN
-- Adapted from: http://searchvb.techtarget.com/tip/0,289483,sid8_gci932171,00.html
-- Added recid (identity column)
-- Tests
/*
  select * from fnSplit('12345', ',')
  select * from fnSplit('1,22,333,444,,5555,666', ',')
  select * from fnSplit('1##22#333##444','##')  --note second item has embedded #
  select * from fnSplit('1 22 333 444  5555 666', ' ')
*/
DECLARE @sItem VARCHAR(8000)
WHILE CHARINDEX(@sDelimiter,@sInputList,0) <> 0
 BEGIN
 SELECT
  @sItem=RTRIM(LTRIM(SUBSTRING(@sInputList,1,CHARINDEX(@sDelimiter,@sInputList,0)-1))),
  @sInputList=RTRIM(LTRIM(SUBSTRING(@sInputList,CHARINDEX(@sDelimiter,@sInputList,0)+LEN(@sDelimiter),LEN(@sInputList))))
 
 IF LEN(@sItem) > 0
  INSERT INTO @List SELECT @sItem
 END
IF LEN(@sInputList) > 0
 INSERT INTO @List SELECT @sInputList -- Put the last item in
RETURN
END
GO


Sample Usage via a Cursor:


declare
@recid int
, @item varchar(8000)
, @SampleData varchar(50)
set @SampleData = 'Item1,Item2,Item3,Item4,Item5'
declare split cursor for select * from dbo.fnSplit(@SampleData, ',')
open split
while 1=1 begin
fetch next from split into @recid, @item
if @@fetch_status <> 0 break
-- Do something here...
select @recid, @item
end
close split
deallocate split

Tags:

SQL Server

Workflow Hosted via Windows Communication Foundation

by 11. August 2008 22:22

Instance management techniques for WFC: http://msdn.microsoft.com/en-us/magazine/cc163590.aspx

Windows Communication Foundation (WCF), Windows Workflow Foundation (WF) and Windows CardSpace Samples

Brief Description
Samples for Windows Communication Foundation (WCF), Windows Workflow Foundation (WF) and Windows CardSpace

http://www.microsoft.com/downloads/details.aspx?FamilyId=2611A6FF-FD2D-4F5B-A672-C002F1C09CCD&displaylang=en

Tags:

Windows Communication Foundation | Workflow Foundation

Workflow Foundation

by 11. August 2008 18:18

Workflow Persistence to SQL Server database, recommended to create two separate databases and run scripts as shown below. 

WorkflowPersistence (db) WorkflowPersistence.bak (1.46 mb) SqlPersistenceService_Schema.sql (4.20 kb) SqlPersistenceService_Logic.sql (23.34 kb)

WorkflowTracking (db) WorkflowTracking.bak (1.89 mb) Tracking_Schema.sql (49.61 kb) Tracking_Logic.sql (372.66 kb)

Note: The default location of attached SQL scripts listed above is: C:\Windows\Microsoft.NET\Framework\v3.0\Windows Workflow Foundation\SQL\EN

 

 

Tags:

Workflow Foundation

Remote Desktop Connections

by 11. August 2008 16:57

Connecting remotely using %SystemRoot%\System32\mstsc.exe (run with /? for list of command line parameters).

When attempting to connect via RDC, the server will typically only support a fixed number of active connections (in my experience with various Windows servers it is typically 2).  This means that only two different users can be connected at the same time.  Also, when users don’t log off properly (i.e. by closing the client window vs. actually logging off) their session stays connected even though they no longer have a client window open to it.  This is usefull if you want to leave a process running, leave windows open, etc., close your client window and re-connect later to pick up where you left off.  However, the downside is that you will be blocking one of the available connections thus preventing other new sessions.  Should the machine become inaccessible due to too many active connections you have four basic options of recovery (shown below).

  1. Launch "All Programs" > "Administrative Tools" > “Terminal Services Manager” and then expand the "All Listed Servers" treeview on the left pane.  You should see your domain name there, double-click to load list of all available machines.  Find the machine in question and click on it to view the active connections in the right pane.  You can right-click on any of the connections in the right pane and perform several actions such as ("Send Message", "Disconnect","Reset", etc.).  Typically, you will select "Reset" on the connections that are inactive.
  2. mstsc /console” command. This will launch the same Remote Desktop Client you use every day; however, it will connect you in Console Mode. Console Mode means connecting to the server as if you were actually on the server using the server’s keyboard and mouse.  Only one person can be connected in console mode at a time.  Once you get on the machine in Console Mode you can launch “Terminal Service Manager” to view the disconnected sessions and reset them to reclaim the connections as described in option 1 above.
  3. qwinsta /SERVER:servername” command. This display the connections on the machine in question.  You can then run "rwinsta {sessionname | sessionid} /SERVER:servername" command to reset the desired connection.
  4. Method of last resort, get on the physical machine and perform option 1 above.  This is the same as option 1 and 2 other than you need to get on the physical machine. 

Tags:

Windows

Asp.Net Intermittent Login Error

by 10. August 2008 04:43

This was happening sporadically (e.g. I was able to login without this error several times and then got the error other times, John seemed to get the error every time he attempted to login).  The strangest part of this issue is that there is nothing in the configuration the points to a SQL Express database.  There was only one connection string entry and it pointed to the standard SQL database being used elsewhere in the site and in other sites (i.e. HTT, RoadAdz, etc.).  For testing purposes I created a new site with full copy of the original site, except for the web.config file which I created fresh in the new site.  So far the new site has not produced this error, emailed John 8/8 @ 11:02pm asking him to try the new site and provide me his feedback.  Waiting on Johns response to proceed.

Here is the error message: 

Server Error in '/' Application.


An error has occurred while establishing a connection to the server.  When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Shared Memory Provider, error: 40 - Could not open a connection to SQL Server)

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
SQLExpress database file auto-creation error:

The connection string specifies a local Sql Server Express instance using a database location within the applications App_Data directory. The provider attempted to automatically create the application services database because the provider determined that the database does not exist. The following configuration requirements are necessary to successfully check for existence of the application services database and automatically create the application services database:

  1. If the applications App_Data directory does not already exist, the web server account must have read and write access to the applications directory. This is necessary because the web server account will automatically create the App_Data directory if it does not already exist.
  2. If the applications App_Data directory already exists, the web server account only requires read and write access to the applications App_Data directory. This is necessary because the web server account will attempt to verify that the Sql Server Express database already exists within the applications App_Data directory. Revoking read access on the App_Data directory from the web server account will prevent the provider from correctly determining if the Sql Server Express database already exists. This will cause an error when the provider attempts to create a duplicate of an already existing database. Write access is required because the web server accounts credentials are used when creating the new database.
  3. Sql Server Express must be installed on the machine.
  4. The process identity for the web server account must have a local user profile. See the readme document for details on how to create a local user profile for both machine and domain accounts.


Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

 

[SqlException (0x80131904): An error has occurred while establishing a connection to the server.  When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Shared Memory Provider, error: 40 - Could not open a connection to SQL Server)]   System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +800131   System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +186   System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject) +737554   System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) +114   System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) +421   System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +181   System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +173   System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +133   System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup) +27   System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +47   System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +105   System.Data.SqlClient.SqlConnection.Open() +111   System.Web.Management.SqlServices.GetSqlConnection(String server, String user, String password, Boolean trusted, String connectionString) +68[HttpException (0x80004005): Unable to connect to SQL Server database.]   System.Web.Management.SqlServices.GetSqlConnection(String server, String user, String password, Boolean trusted, String connectionString) +124   System.Web.Management.SqlServices.SetupApplicationServices(String server, String user, String password, Boolean trusted, String connectionString, String database, String dbFileName, SqlFeatures features, Boolean install) +86   System.Web.Management.SqlServices.Install(String database, String dbFileName, String connectionString) +25   System.Web.DataAccess.SqlConnectionHelper.CreateMdfFile(String fullFileName, String dataDir, String connectionString) +397

Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.1433

Tags:

[None]