How To Query A Database That's Being Used By Asp.Net - asp.net

I have a Sql Server 2008 Express database file that's currently being used by an ASP.NET application, and I'm not sure how to query the database without taking the website down.
I'm unable to copy the database files (.mdf and .ldf files) to another directory, since they're in use by the web server. Also, if I attach the databases to an instance of the sql server (using the 'Create Database [DB name] on (filename = '[DB filename.mdf]') for attach;' command at the sqlcmd prompt), then the application pool user becomes unable to access the database (i.e. the webpages start producing http 500 errors. I think this might have to do with the username for the application pool becoming somehow divorced from the login credentials in the sql server database).
Any suggestions? I realize this is probably a newbie question, since it seems like a rather fundamental task. However, due to my inexperience, I really don't know what the answer is, and I'm pretty stumped at this point, since I've tried a couple of different things.
Thanks!
Andrew

if I attach the databases to an instance of the sql server (using the 'Create Database [DB name] on (filename = '[DB filename.mdf]') for attach;' command at the sqlcmd prompt),
Don't do this to a live database - it's attempting to be setup an MDF to be written to by two different databases...
Use Backup/Restore
As you've found, Attach/ReAttach requires the database to be offline - use the Backup/Restore functionality:
MSDN: Using SSMS to Backup the Database
MSDN: Using SSMs to Restore the Backup
Be aware that the backup/restore doesn't maintain logins (& jobs if you have any associated with the database) - you'll have to recreate & sync if using an account other than those with uber access.
Maybe Linked Server would work?
Another alternative would be to setup another SQL Server Express/etc instance on a different box, and use the Linked Server functionality to create a connection to the live/prod data. Use a different account than the one used for the ASP application...

Related

Various difficulties creating ASP.NET Session tables via aspnet_regsql.exe

We're trying to move ASP.NET session state for one of our Azure web apps into a database, and it seems like the aspnet_regsql.exe tool is the way to go. Unfortunately, I'm getting stuck on a few issues below. It's an Azure SQL database, and I'm connecting using the server's admin account.
I initially wanted to add the session tables to our existing database, so I ran .\aspnet_regsql.exe -U adminusername -P adminpassword -S servername.database.windows.net -d databasename -ssadd -sstype c. Which throws the exception "Database 'databasename' already exists. Choose a different database name"
Omitting the database name and running it again throws the exception: "Execution Timeout Expired" after about 30 seconds, which is just the default for SqlCommand.CommandTimeout. This occurs while executing the "CREATE DATABASE" command. I tried creating a database manually, and it takes about 50 seconds for some reason. This database is S0 tier and is not under any load
Running aspnet_regsql again on the already-created database (because it's idempotent, right?) leads to the "Database already exists" error, as does pre-creating an empty database for it to start from.
There's no flag that lets me increase the timeout, and I can't set command timeout using the -C (connection string) flag
Adding the -sqlexportonly flag to generate a script and just running that directly doesn't work either (yes, I know I'm not supposed to run InstallSqlState.sql directly). It throws a whole load of error messages saying things like:
Reference to database and/or server name in 'msdb.dbo.sp_add_job' is not supported in this version of SQL Server.
USE statement is not supported to switch between databases.
Which makes me think this script might have some issues with an Azure SQL database...
Does anyone have any ideas?
Update:
It looks like all the errors involving 'msdb' are related to removing and re-adding a database job called 'Job_DeleteExpiredSessions'. Azure SQL doesn't support database jobs, so the only options I can see are
Run SQL on a VM instead (vastly more expensive, and I'd rather stick with the platform services than have to manage VMs)
Implement one of those "Elastic Job Agents"
Perhaps move the same functionality elsewhere (e.g. a stored proc)?
Turns out Microsoft has an article about how to do exactly what I need, which I somehow
missed during my searching yesterday. Hopefully this answer saves someone else a few hours of frustration. All the info you need is at https://azure.microsoft.com/en-au/blog/using-sql-azure-for-session-state/ earlier.
Note that YMMV since it's from 2010 and also says in scary red letters
"Microsoft does not support SQL Session State Management using SQL Azure databases for ASP.net applications"
Nevertheless, they provide a working script that seems to do exactly what I need.

How to create a small and simple database using Oracle 11 g and SQL Developer?

How to create a small and simple database using Oracle 11 g and SQL Developer ?
I am seeing too many errors and I cannot find any way to make a simple database.
For example
create database company;
Caused the following error:
Error starting at line 1 in command:
create database company
Error at Command Line:1 Column:0
Error report:
SQL Error: ORA-01501: CREATE DATABASE failed
ORA-01100: database already mounted
01501. 00000 - "CREATE DATABASE failed"
*Cause: An error occurred during create database
*Action: See accompanying errors.
EDIT-
This is completely different from MySQL and MS-SQL that I am familiar with.
Not as intuitive as I was expecting.
First off, what Oracle calls a "database" is generally different than what most other database products call a "database". A "database" in MySQL or SQL Server is much closer to what Oracle calls a "schema" which is the set of objects owned by a particular user. In Oracle, you would generally only have one database per server (a large server might have a handful of databases on it) where each database has many different schemas. If you are using the express edition of Oracle, you are only allowed to have 1 database per server. If you are connected to Oracle via SQL Developer, that indicates that you already have the Oracle database created.
Assuming that you really want to create a schema, not a database (using Oracle terminology), you would create the user
CREATE USER company
IDENTIFIED BY <<password>>
DEFAULT TABLESPACE <<tablespace to use for objects by default>>
TEMPORARY TABLESPACE <<temporary tablespace to use>>
You would then assign the user whatever privileges you wanted
GRANT CREATE SESSION TO company;
GRANT CREATE TABLE TO company;
GRANT CREATE VIEW TO company;
...
Once that is done, you can connect to the (existing) database as COMPANY and create objects in the COMPANY schema.
Actually the answer from Justin above could not be more incorrect. SQL Server and MySQL are for smallish databases. Oracle is for large enterprise databases, thus the difference in it's structure. And it is common to have more than one Oracle database on a server provided that the server is robust enough to handle the load. If you received the error posted above then you obviously are trying to create a new Oracle database and if you are doing that then you probably already understand the structure of an Oracle database. The likely scenario is that you attempted to create a database using dbca, it initially failed, but the binaries were created. You then adjusted your initial parameters and re-tried creating the database using dbca. However, the utility sees the binaries and folder structure for the database that you are creating so it thinks that the database already exists but is not mounted. Dropping the database and removing the binaries and folders as well as any other cleanup of the initial attempt should be done first, then try again.
From your question description, I think you were to create a database schema, not a database instance. In Oracle terminology, a database instance is a set of files in the file system. It's more like data files in MySQL. Whereas database in MySQL is somewhat equivalent to Oracle's schema.
To create a schema in Oracle: https://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_6014.htm
To create a database instance in Oracle (I personally prefer CDBA):
https://docs.oracle.com/cd/E11882_01/server.112/e25494/create.htm#ADMIN11068
Notice the Oracle Express edition does not support mounting more than one database instance at one time.

what's the issue with AttachDbFilename

Apparently, using AttachDbFilename and user instance in your connection string is a bad way to connect to a DB. I'm using SQL server express on my local machine and it all seems to work fine. But what's the proper way to connect to SQL server then?
Thanks for your explanation.
Using User Instance means that SQL Server is creating a special copy of that database file for use by your program. If you have two different programs using that same connection string, they get two entirely different copies of the database. This leads to a lot of confusion, as people will test updating data with their program, then connect to a different copy of their database in Management Studio, and complain that their update isn't working. This sends them through a flawed series of wild goose chase steps trying to troubleshoot the wrong problem.
This article goes into more depth about how to use this feature, but heed the very first note: the User Instance feature has been deprecated. In SQL Server 2012, the preferred alternatives are (in this order, IMHO):
Create or attach your database to a real instance of SQL Server. Your connection string will then just need to specify the instance name, the database name, and credentials. There will be no mixup as Management Studio, Visual Studio and your program(s) will all be connecting to a single copy of the database.
Use a container for local development. Here's a great starter video by Anna Hoffman and Anthony Nocentino, and I have some other resources here, here, and here. If you're on an M1 Mac, you won't be able to use a full-blown SQL Server instance, but you can use Azure SQL Edge if you can get by with most SQL Server functionality (the omissions are enumerated here).
Use SqlLocalDb for local development. I believe I pointed you to this article yesterday: "Getting Started with SQL Server 2012 Express LocalDB."
Use SQL Server Compact. I like this option the least because the functionality and syntax is not the same - so it's not necessarily going to provide you with all the functionality you're ultimately going to want to deploy. Compact Edition is also deprecated, so there's that.
Of course if you are using a version < SQL Server 2012, SqlLocalDb is not an option - so you should be creating a real database and using that consistently. I only mention the Compact option for completeness - I think that can be almost as bad an idea as using AttachDbFileName.
EDIT: I've blogged about this here:
Bad Habits : Using AttachDBFileName
In case someone had the problem.
When attaching the database with a connection string containing AttachDBFile
with SQLEXPRESS, I noticed this connection was exclusive to the ASP.NET application that was using the database. The connection did block the access to all other processes on the file level when made with System.Data.SqlClient as provider.
In order to assure the connection to be shareable with other processes
instead use DataBase to specify the database name in your connection string
Example or connection string :
Data Source=.\SQLEXPRESS;DataBase=PlaCliGen;User ID=XXX;password=ZZZ; Connect Timeout=30
,where PlaCliGen is the name (or logical name) by which SQLEXPRESS server knows the database.
By connecting to the data base with AttachDBFile giving the path to the .mdf file
(namely : replacing DataBase = PlacliGen by AttachDBFile = c:\vs\placligen\app_data\placligen.mdf) the File was connected exclusively and no other process could connect to the database.

Moving SQL Server from local computer to server

I kind of new to SQL Server, I always used access db for my sites.
I created a SQL Server on my local computer and now I want to take this db and transfer it to the server. In access all I had to do is, take the mdb file and put it on the server and change the connection string. How can I transfer the SQL Server db to the server?
Is there any file to put on the server ?
Also the connection string isn't a folder but a local computer like this:
Data Source=my-PC;Initial Catalog=storeSQL1;User ID='my-PC\com';Password='';Trusted_Connection=YES;
Who can provide me this connection string for the server (the hosting company) ?
The easiest way would probably be to create a backup of the database on your local machine, then restore that backup on the new server.
Roadmap is:
Do simple backup-restore to move user databases to target server.
Create script on source server, that can recover permissions and login-users pairing
Restore the CLR and TRUSTWORTHY security for databases, that using unsafe assemblies, simpliest way is (in proper DB):
exec sp_changedbowner 'sa' --sa just for example
ALTER DATABASE dbname SET TRUSTWORTHY ON
Enjoy
Depending on your version of SQL Server here is a good article that outlines all the ways to move a SQL Server Database.
http://blogs.msdn.com/b/sreekarm/archive/2009/09/11/move-a-database-from-one-server-to-another-server-in-sql-server-2008.aspx
As for getting the connection string yes the hosting company would provide you with that. Where is the database hosted, you could check their knowledge base articles or if it's an in house data base I'm sure a dba could provide you with that information. It won't change much from what you have but it will change.
I'm not sure what tools your using, but to start you need to do a dump or backup of your current database on your machine. After you do that then you can do and import which should create all the tables and import any data you have.
After the data exists on the server then as far as the connection string, you just need to say the Data Source is the server ip address or host name and change your User ID and Pass to match that server.
If you need more details on any part of this process, post what tools your using and what your environment looks like and I would be more than happy to assist you.
In my opinion the best way to do that is to detach the db from one server(pc), copy the files to the second one and then attach them on the second server/pc.
To detach:
USE master;
GO
EXEC sp_detach_db #dbname = N'AdventureWorks2008R2';
GO
To attach:
USE master;
GO
CREATE DATABASE MyAdventureWorks
ON (FILENAME = 'C:\MySQLServer\AdventureWorks2008R2_Data.mdf'),
(FILENAME = 'C:\MySQLServer\AdventureWorks2008R2_Log.ldf')
FOR ATTACH;
GO

Pull Sybase data into SQL Server

I have an ASP.NET app that uses a SQL Server database. I now need to pull data from Sybase ASE into that SQL Server database for my app to consume, and I'm not having any success with my ideas.
Has anyone done this? Any ideas/suggestions/tips?
You can configure a linked server from SQL Server to Sybase. It should be fairly vanilla using the Sybase provider on the MS side.
Okay, I've finally (through lame trial and error) found out how to link my Sybase ASE (12.5) server to my SQL Server (2008) which will allow the integration I want. Here's roughly how I did it:
Logged in to Sybase ASE OLE DB Configuration Manager (this is like the Sybase version of Windows' ODBC Data Sources) and added an OLE DB data source. I believe you must be an admin on the PC to do this.
In SQL Server 2008 Management Studio, went to Server Objects > Linked Servers. Right click and select "New Linked Server".
In the Linked Server Properties, I set the following properties:
General:
--Linked server: the name of your linked server as you want it to appear in your linked server list
--Provider: Select Sybase ASE OLE DB Provider from the dropdown list.
--Product name: The exact name of the OLD DB data source you just created in Sybase ASE OLE DB Configuration Manager.
--Data source: Same as Product name.
--Provider string: I left this blank
--Location: I left this blank
--Catalog: The default database (master or whatever) to log on to.
Security:
--You need to map a valid SQL Server logon to a valid Sybase logon. I did not use impersonation (which does a credentials pass-thru).
--I chose my connection Be made without using a security context.
Server Options:
--All the defaults worked for me.
Throughout, the standard SQL Server help worked fairly well as a guide. Though not always true, F1 was my friend here.
I can now do distributed queries, DTS or SSIS packages, and use SSRS. This takes a lot of the suck out of Sybase ASE.
Of course the above can be done via the command line using sp_linkserver, but the GUI is more comfortable for a lowly dev like me.
Use Management Studio or Enterprise Manager to import the data using the data importation wizard. That should be it, just make sure you pick the right data provider in the wizard and you should be good to go.
If you want this to be a live feed create a small windows service to manage the exchange of information. It should be relatively simple to do, just a little bit of leg work on your end. If you are adverse to that there are plenty of off the shelf solutions that can do this for you.
The question is a little vague on specifics:
Is this a one time conversion or part of a repeated process.
Is the source machine "reachable" from your destination machine (can you connect the two or do you need to read in files)
With most conversions there are two parts:
Physically getting data from the source into the destination.
Mapping data from the source to the destination tables.
It is hard to make any recommendations without more info. What would be fine for a one time conversion would not work if you need to read in data all day every day. Also, if the source database can not be connected to and you have to pass files, they methods change.

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